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This document is a student guide for a Qualcomm training course on Long Term Evolution (LTE/FDD) Fundamentals. It provides an outline of the course, which covers the evolution of 3GPP networks, the key aspects and performance targets of LTE, the LTE network architecture including E-UTRAN and EPC, and the protocol layers of E-UTRAN. It also defines various 3GPP terminology and lists many common LTE acronyms.

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MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Long Term Evolution (LTE/FDD) Fundamentals Long Term Evolution (LTE/FDD) Fundamentals Student Guide 80-W1738-1 Rev B
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION About Qualcomm University Qualcomm University (“QU”) offers the advanced technology training solutions you need to stay on the cutting edge of wireless technology. Visit the QU website for more information about individual training products, international training centers, and distance learning opportunities, along with a complete list of classes—all developed by QUALCOMM Incorporated, the pioneers of CDMA. Qualcomm University: www.qualcommuniversity.com QUALCOMM Incorporated: www.qualcomm.com Notes iii
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Where Can I Learn More? Want to learn more? Qualcomm University offers additional in-depth technical training related to this course. To view a map of all current training offerings or get more information, go to: www.qualcommuniversity.com Notes iv
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION vii Acronyms and Abbreviations 16-QAM 16-Quadrature Amplitude Modulation 3G 3rd G eneration 3GPP 3rd Generation Partnership Project AAA Authentication, Authorization and Accounting ACK Acknowledgment AIPN All-IP Network AM Acknowledged Mode AMBR Aggregate Maximum Bit Rate AMC Adaptive Modulation and Coding AN Access Network A/N ACK/NAK ARQ Automatic Repeat Request AS Access Stratum AT Access Terminal BCCH Broadcast Control Channel BCH Broadcast Channel BSR Buffer Status Report BW BandWidth CCCH Common Control Channel CCE Carrier Class Ethernet CDMA Code Division Multiple Access CDS Channel Dependent Scheduling CN Core Network CP Cyclic Prefix CQI Channel Quality Indicator CRC Cyclic Redundancy Check C-RNTI Cell Radio Network Temporary Identifier CS Circuit Switched CW Code Word DCCH Dedicated Control Channel DCI Downlink Control Information DL Downlink DL-SCH Downlink Shared Channel DM Demodulation DM-RS Demodulation Reference Signal DRX Discontinuous Transmission DTCH Dedicated Traffic Channel E-AGCH Enhanced Absolute Granting Channel E-DPCCH Enhanced Dedicated Physical Control Channel E-DPDCH Enhanced Dedicated Physical Data Channel E-HICH Enhanced Hybrid Indicator Channel eNB Evolved Node B EPC Evolved Packet Core EPS Evolved Packet System; LTE and SAE
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION viii E-RGCH Enhanced Relative Granting Channel E-UTRA Evolved UMTS Terrestrial Radio Access; PHY aspects E-UTRAN Evolved UMTS Terrestrial Radio Access Network; MAC / L2 / L3 aspects FD Full-Duplex FDD Frequency Division Duplex FDM Frequency Division Multiplexing FDMA Frequency Division Multiple Access FFT Fast Fourier Transform FL Forward Link GERAN GSM/EDGE Radio Access Network GGSN GPRS Gateway Support Node GPRS General Packet Radio Service GSM Global System for Mobiles (European standard) GW Gateway HA Home Agent HARQ Hybrid ARQ HD Half-Duplex HLR Home Location Register HO Handover HRPD High Rate Packet Data HSDPA High Speed Downlink Packet Access HS-DPCCH High Speed Dedicated Control Channel HSPA High-Speed Packet Access HSPA+ High-Speed Packet Access evolved or enhanced HS-PDSCH High Speed Physical Downlink Shared Channel HSS Home Subscriber Service HS-SCCH High Speed Shared Control Channel HSUPA High Speed Uplink Packet Access IDFT Inverse Discrete Fourier Transform IFDMA Interleaved Frequency Division Multiple Access IMS IP Multimedia Subsystem IP Internet Protocol L1 Layer 1 L2 Layer 2 LAN Local Area Networks LFDM Localized Frequency Division Multiplexing LFDMA Localized Frequency Division Multiple Access LTE Long Term Evolution MAC Medium Access Control MBMS Multimedia Broadcast Multicast Service MBSFN Multimedia Broadcast over a Single Frequency Network MCCH Multicast Control Channel MCH Multicast Channel MCS Modulation and Coding Schemes MIMO Multiple-Input-Multiple-Output MME Mobility Management Entity
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Outline 1. Network Architecture: Evolution & Protocols 2. E-UTRA Essentials 3. Downlink Channels and Procedures 4. Uplink Channels and Procedures 5. What is Next? Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 1 SECTION Network Architecture: Evolution & Protocols Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section 1 Objectives ¾Describe 3GPP technology evolution. ¾List the key performance requirements for LTE. ¾Distinguish the evolved UTRAN network architecture. ¾Describe the functions of the layers within the E-UTRAN protocol structure. Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 3GPP UMTS and WCDMA Releases & Features UMTS and WCDMA Releases and Features Release 99 – Specified the first UMTS 3G networks, incorporating a CDMA air interface. Release 4 – Introduced mainly the CS Core Network split feature plus other minor enhancements. Release 5 – Introduced mainly IMS, HSDPA (allowing broadband services on the Downlink), and other minor enhancements. Release 6 – Integrated operation with Wireless LAN networks and added HSUPA (enables broadband uploads and services), MBMS, and enhancements to IMS such as Push-to-Talk over Cellular (PoC), video conferencing, messaging, etc. Release 7 – Significant progress made in 2006 and 2007 toward completion of this release. Most documents are under revision control. Introduced, among other features, enhancements to High-Speed Packet Access (HSPA+), QoS, and improvements to real-time applications like VoIP. Release 8 – In progress (expected 2009). Introducing, among others, E-UTRA (also called LTE, based on OFDMA), All-IP Network (also called SAE), and Femto cells operation. Release 8 constitutes a re-factoring of UMTS as an entirely IP based fourth-generation network. 3GPP RAN approved the LTE Physical Layer specifications in September 2007. The specifications are 36.201–36.214 and are on the 3GPP site at http://www.3gpp.org/ftp/Specs/html-info/36-series.htm. Each release incorporates hundreds of individual standards documents, each of which may have gone through many revisions. Current 3GPP standards incorporate the latest revision of the GSM standards. Standards documents are available for free on the 3GPP Web site. These standards cover the radio component (Air Interface) and the Core Network, as well as billing information and speech coding down to source code level. Cryptographic aspects (authentication, confidentiality) are also specified in detail. More details about the 3GPP releases content can be found at http://www.3gpp.org/specs/releases-contents.htm and http://www.3gpp.org/Management/WorkPlan.htm.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION LTE and EPS Terminology • Long Term Evolution (LTE): Evolution of 3GPP UMTS Terrestrial Radio Access (E-UTRA) technology • Evolved Packet System (EPS): Evolution of the complete 3GPP UMTS Radio Access, Packet Core and its integration into legacy 3GPP/non-3GPP networks. It includes: – Radio Access Network – Evolved UTRA Network (E-UTRAN) – System architecture – Evolved Packet Core (EPC) • This course uses the terms LTE and E-UTRA interchangeably. Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Design Performance Targets • Scalable transmission bandwidth (up to 20 MHz) • Improved Spectrum Efficiency – Downlink (DL) spectrum efficiency should be 2-4 times Release 6 HSDPA. ‹ Downlink target assumes 2x2 MIMO for E-UTRA and single TX antenna with Type 1 receiver HSDPA. – Uplink (UL) spectrum efficiency should be 2-3 times Release 6 HSUPA. ‹ Uplink target assumes 1 TX antenna and 2 RX antennas for both E-UTRA and Release 6 HSUPA. • Coverage – Good performance up to 5 km – Slight degradation from 5 km to 30 km (up to 100 km not precluded) • Mobility – Optimized for low mobile speed (< 15 kph) – Maintained mobility support up—to 350 kph (or even up to 500 km/h) • Advanced TX schemes and multiple-antenna technologies • Inter-working with existing 3G and non-3GPP systems – Interruption time of real-time or non-real-time service handover between E-UTRAN and UTRAN/GERAN shall be less than 300 or 500 ms. User Throughput and Spectrum Efficiency Requirements Detailed throughput requirements: z Downlink: – 5%-tile Downlink user throughput per MHz 2-3 times Release 6 HSDPA – Average Downlink user throughput per MHz 3-4 times Release 6 HSDPA – Downlink spectrum efficiency should be 3-4 times Release 6 HSDPA – Downlink performance targets assume 2 transmit and 2 receive antennas for E-UTRA, and 1 transmit and enhanced Type 1 receiver for Release 6 HSDPA – Downlink user throughput should scale with spectrum allocation z Uplink: – 5%-tile Uplink user throughput per MHz 2-3 times Release 6 HSUPA – Average Uplink user throughput per MHz 2-3 times Release 6 HSUPA – Uplink spectrum efficiency should be 2-3 times Release 6 HSDPA – Uplink performance targets assume 1 transmit and 2 receive antennas for both E-UTRA and Release 6 HSDPA – Uplink user throughput should scale with spectrum allocation and mobile maximum transmit power E-UTRA is expected to outperform Release 6 HSPA by a factor of 2-4 in user throughput and spectrum efficiency. This assumes a maximum cell range up to 5 km. For cell ranges up to 30 km, slight degradations are expected for the achieved performance for the user throughput targets and more significant degradation for the spectrum efficiency targets. However, cell ranges up to 100 km should not be precluded by the specifications.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Main drivers for the evolution: • Faster RRM response for CDS (Channel Dependent Scheduling) • Reduced packet latencies • Interworking with other radio access technologies (GSM, HSPA, HRPD) UMTS Network Architecture Evolution Concepts Centric RRM (RNC-Based) (Dumb Base Stations, Smarter RNCs) Multi-hop user data forwarding 4 NW Nodes (NodeB, RNC, SGSN, GGSN) Dual-hop user data forwarding 2 NW Nodes (NodeB, PGW) Distributed RRM (NodeB-based) (smarter Base Stations, not so smart RNC) Interworking with 3GPP technologies only Interworking with 3GPP and non-3GPP technologies Network Architecture Evolutionary Concepts: Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 3GPP Network Architecture Evolution - 4 functional entities on Control and User Planes - RNC-based RRM Control Plane User Plane R99 NodeB RNC GGSN SGSN - Flat Architecture: 2 functional entities on User Plane - E-NodeB-centric RRM Control Plane User Plane E-UTRAN E-NodeB MME SGW/PGW Control Plane User Plane HSPA RNC RNC NodeB GGSN SGSN - Node B performs most of RRM for High Speed DL/UL channels Control Plane User Plane HSPA with Direct Tunneling RNC RNC SGSN GGSN NodeB - User data Packets are directly forwarded to GGSN Main Drivers: z Faster RRM response for CDS z Reduced packet latencies Network Architecture Evolution (decentralization process) z From a centric RNC-Based RRM (stupid Base Stations and smarter RNCs) z To a decentralized Base Station-based RRM (smarter Base Stations, less smart RNCs) z From user packet data forwarding to GGSN through RNC (intermediary RNCs) z To direct user packet data forwarding to GGSN (Direct Tunneling)
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section Overview • 3GPP UMTS Evolution Roadmap and Terminology • UTRAN Evolution Toward E-UTRAN • E-UTRAN Network Nodes, Protocol Structure, and Functionalities • EPS Integrated Architecture Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Enhanced Node B (eNB) Functions • Radio Resource Management: – Radio Bearer Control – Admission/congestion control – Connection and mobility control – UL/DL dynamic scheduling • IP header compression and encryption of user data • Selection of an MME at UE attachment (if necessary) • Routing of User Plane data towards S-GW • Routing of paging messages from MME towards UE • Measurement and reporting configuration eNB MME / S-GW / P-GW MME / S-GW / P-GW eNB eNB S1 S 1 S 1 S 1 X2 X 2 X 2 E-UTRAN EPC Reference 23.401 z eNB (Evolved Node B) provides the E-UTRA User Plane (PDCP/RLC/MAC/PHY) and Control Plane (RRC) protocol terminations towards the UE. z The eNBs are logically interconnected with each other by means of the X2 interface. z The eNBs are also connected by means of the S1 interface to the EPC (Evolved Packet Core), more specifically to the MME (Mobility Management Entity) by means of the S1-MME and to the Serving Gateway (S-GW) by means of the S1-U. z The S1 interface supports a many-to-many relation between MMEs / Serving Gateways and eNBs.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Serving Gateway (S-GW) & P-GW Functions S-GW • Local Mobility Anchor point for inter-eNB handover • Mobility anchoring for inter-3GPP mobility • E-UTRAN Idle Mode Downlink packet buffering and initiation of network triggered service requests • Lawful interception • Packet routing and forwarding • Transport level packet marking in the UL and DL • UL and DL charging per UE, PDN, and QCI • Termination of U-plane packets • Switching of U-plane for support of UE mobility P-GW •Per-user based packet filtering •Lawful interception •UE IP address allocation •DL rate enforcement based on AMBR For more details, see 3GPP TS 23.401 eNB MME / S-GW / P-GW MME / S-GW / P-GW eNB eNB S1 S 1 S 1 S 1 X2 X 2 X 2 E-UTRAN EPC Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MME Functions • NAS signaling and its security • AS Security Control • Inter CN node signaling for mobility between 3GPP access networks • Idle mode UE Reachability (including control and execution of paging retransmission) • Tracking Area List Management (idle and active) • PDN GW and Serving GW selection • MME selection for handovers with MME change • Idle state mobility control • SGSN selection for 3GPP handovers • Roaming and Authentication • EPS bearer management For more details, see 3GPP TS 23.401 eNB MME / S-GW / P-GW MME / S-GW / P-GW eNB eNB S1 S 1 S 1 S 1 X2 X 2 X 2 E-UTRAN EPC Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRAN Protocol Stack: User Plane eNB S-GW eNB S 1 - U P X2-UP Uu P-GW S5 IP Networks References: • LTE-Uu: 36.201 (Physical Layer), 36.321 (MAC), 36.322 (RLC), 36.323 (PDCP) • S1: 36.411 (Physical Layer), 36.414 (S1- Data Transport) • X2: 36.421 (Physical Layer); 36.424 (X2 – Data Transport) Transport Layer reference for the S1 and X2 Interfaces: IP in E-UTRAN - Used in user and control planes - IP in E-UTRAN shall also support: 1. NDS/IP (Network Domain Security for IP): Sets up Confidentiality and Integrity for data exchange between network entities 2. Diffserv (Differentiated Services): Enhancements of the IP protocol for QoS References: RFC2475, An Architecture for Differentiated Services GTP (GPRS Tunneling Protocol) in E-UTRAN - GTP goes over UDP/IP transport protocol stack - No flow or error control or any mechanism to guarantee the data delivery of S1-U interface - As a reminder in 3G, GTP is used over the Iu-PS interface (connection between RNC and SGSN)
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRAN Protocol Stack: Control Plane References: • LTE-Uu: 36.331 (RRC) • S1: 36.412 (Signaling Transport), 36.413 (Application Protocol) • X2: 36.422 (Signaling Transport), 36.423 (Application Protocol) • IETF RFC 2960 (Stream Control Transmission Protocol) About the SCTP (Stream Control Transmission Protocol): - It is a reliable connection-oriented transport protocol similar to TCP - As TCP, SCTP implements Congestion and flow control, detection of data corruption and loss/duplication of packets - SCTP connection needs to be set up connection between peers before actual data transmission (as TCP) - From functional perspective, there are some key new features in SCTP: 1. Multi-streaming - 2. Multi-homing - 3. Message Level Framing 1. Multi-streaming: - In SCTP protocol, a stream is a unidirectional sequence of user data delivered to upper layers - With Multi-streaming, SCTP allows to set up several independent streams between two peers. With this feature, if transmission error occur in one stream, it does not affect the other streams. - This feature is important for signaling transfers between two nodes of UTRAN where, for instance, the delivery order of each user signaling flow can be preserved, but hey can be delivered independently. - TCP, however, in some instances can also use multiple parallel streams. Example of this is the downloading of web-pages with multiple multimedia objects. 2. Multi-homing - Allows SCTP endpoint to be reached through multiple network addresses - In case of error in one of the address, the retransmitted packets may be sent to an alternate address providing redundancy operation 3. Message level Framing - SCTP works at message level whereas TCP is octet based framing and does not preserve transmitted data structure - In SCTP, messages are transmitted as whole set of bytes if the maximum SCTP length is not reached - This is an advantage for E-UTRAN signaling transport Reference Documents: RFC2960 Stream Control Transmission Protocol
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION HA S6a S2a IS-835 IS-835 HS/AAA AAA Ta S101 S2a 1xEVDO Abis PDSN RNC AT AN EPS Architecture S12 Uu UE SGSN Iu CP NodeB RNC S3 Iub Gr HLR/HSS S6a PCRF S7 S1-CP S11 IP Networks UE S1-U LTE-Uu E-NodeB SAE-GW (PDN-GW/S-GW) MME 3GPP TS 23.401 V8.2.0 (2008-06) Technical Specification Group Services and System Aspects; General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access (Release 8). PCRF is the policy and charging control element. PCRF functions are described in more detail in TS 23.203 [6]. z In a non-roaming scenario, there is only a single PCRF in the HPLMN associated with one UE’s IP-CAN session. The PCRF terminates the RX interface and the Gx interface. z In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with one UE’s IP-CAN session: – H-PCRF that resides within the H-PLMN – V-PCRF that resides within the V-PLMN
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 2 SECTION E-UTRA Essentials Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section 2 Objectives ¾ Describe the E-UTRA air interface capabilities. ¾ Recognize DL and UL time/frequency organization. Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Air Interface Capabilities Bandwidth support • Flexible from 1.4 MHz to 20 MHz Waveform • OFDM in Downlink / SC-FDM in Uplink Duplexing mode • FDD: full-duplex (FD) and half-duplex (HD) • TDD Modulation orders for data channels • Downlink: QPSK, 16QAM, 64QAM • Uplink: QPSK, 16QAM, 64QAM MIMO support • Downlink: SU-MIMO and MU-MIMO (SDMA) • Uplink: SDMA Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION UE-eNB Communication Link Single (and same) link of communication for DL & UL Effectively: • DL serving cell = UL serving cell • No UL or DL macro-diversity – UL softer HO reception is an implementation choice – UE’s “Active Set” size = 1 • Hard-HO-based mobility – RACH-based mobility procedure to target cell – Network controlled by default – UE initiated under RL failure condition • Load indicator for inter-cell load control – Transmitted over X2 interface Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Air Interface Peak Data Rates Downlink • ~300 Mbps in 20 MHz • Assumptions: – 4 stream MIMO – 14.29% Pilot overhead (4 TX antennas) – 10% common channel overhead ‹ Note that this overhead level is adequate to serve 1 UE/subframe. – 6.66% waveform overhead (CP + window) – 10% guard band – 64QAM code rate ~1 Uplink • ~75 Mbps in 20 MHz • Assumptions: – 1 TX antenna – 14.3% Pilot overhead – 0.625% random access overhead – 6.66% waveform overhead (CP + window) – 10% guard band – 64QAM code rate ~1 Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Time Domain Organization CP length (config. by higher layer) Number of OFDM Symbols/Slot 4.69µs (Normal CP) 16.66μs (Extended CP) 33.3µs (MBSFN only) 7 OFDM/LFDM symbols 6 OFDM/LFDM symbols 3 OFDM symbols Radio Frame has two Structures: • Type 1 (FS1) for FDD DL/UL • Type 2 (FS2) for TDD This presentation deals only with FS1 Time Domain Organization Basic unit of time Ts, defined with relation to 20 MHz, 15 KHz inter-subcarrier separation and 2048 FFT size (36.211) Ts = 1/(15e3*2048) = 32.55 ns Æ Number of samples in 10 ms is 10 ms/32.55 ns=307200 Tf = 307200Ts = 10 ms Tslot = (307200/20)Ts = 15360Ts z Half radio frame = 5 ms – Contains one sync channel instance – Tailoring efficient HO from GSM z Radio frame = 10 ms – Periodicity of sync channel z PBCH TTI = 40 ms – Periodicity of primary broadcast channel
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Frequency Domain Organization RB SC N ( ) UL RB DL RB N N or Channel Bandwidth [MHz] 1.4 3 5 10 15 20 N. of Occupied Subcarriers including DC (NSC) 73 181 301 601 901 1201 FFT Size 128 256 512 1024 1536 2048 Sampling Rate [MHz] 1.92 ½ 3.84 3.84 7.68 2x3.84 15.36 4x3.84 23.04 6x3.84 30.72 8x3.84 N. of Resource Blocks (NRB) 6 15 25 50 75 100 For 15 KHz Carrier Spacing LTE DL/UL air interface waveforms use a number of orthogonal subcarriers to send user traffic data, Reference Signals (Pilots), and Control Information. Channel Bandwidth and Transmission Bandwidth More information can be found in TS36.101. z OFDM uses all the subcarriers for a single user, whereas OFDMA uses different subcarriers for different users. z There are different types of subcarriers: Data, Pilot, Control, Null, etc. z There are two guard bands at the edges of the OFDM/OFDMA-signal (no RF transmission in these subcarriers). Each guard band exists to avoid interference with adjacent bands. z Taking into account the guard band subcarriers and the DC subcarrier, the number of available subcarriers is as shown in the table.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION UL/DL Resource Grid Definitions Resource Element (RE) • One element in the time/frequency resource grid – One subcarrier in one OFDM/LFDM symbol for DL/UL Resource Block (RB) • Minimum scheduling size for DL/UL data channels • Physical Resource Block (PRB) – 180 kHz x 0.5 ms ‹ 12 subcarriers x 1 slot for 15 kHz subcarrier spacing ‹ 24 subcarriers x 1 slot for 7.5 kHz subcarrier spacing time frequency Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 3 SECTION Downlink Channels & Procedures Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section 3 Objectives ¾Describe DL channel structure and mapping. ¾Provide DL time/frequency OFDMA numerology. ¾Provide DL physical channels resource allocation. ¾Describe overall DL operation. Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Channelization Hierarchy Most DL data traffic is carried on the Down Link Shared Channel (DL-SCH) transport channel and its corresponding Physical Downlink Shared Channel or PDSCH Dedicated Data/Control Paging System broadcast MBSFN Common Control Downlink Physical Signals LOGICAL CHANNELS (What type of information transfer services are offered by the MAC layer) Different kinds of data transfer services as offered by MAC. Each logical channel type is defined by what type of information is transferred z Control Channels (for the transfer of control plane information) z Traffic Channels (for the transfer of user plane information) CONTROL LOGICAL CHANNELS (C-Plane information) – Broadcast Control Channel (BCCH) - System information – Paging Control Channel (PCCH) - Paging information – Multicast Control Channel (MCCH) - Point-to-multipoint channel for MBMS control information – Dedicated Control Channel (DCCH) - Unicast control channel – Common Control Channel (CCCH) - Point-to-multipoint channel used before RRC connection established TRAFFIC LOGICAL CHANNELS (U-Plane information) – Dedicated Traffic Channel (DTCH) - Unicast traffic channel – Multicast Traffic Channel (MTCH) - Point-to-multipoint channel for MBMS traffic TRASPORT CHANNELS (How different type of information is going to transferred over the Air Interface) The physical layer offers information transfer services to MAC and higher layers. The physical layer transport services are described by how and with what characteristics data are transferred over the radio interface: Broadcast Channel (BCH) characterised by: - fixed, pre-defined transport format; requirement to be broadcast in the entire coverage area of the cell. Downlink Shared Channel (DL-SCH) characterised by: - support for HARQ; - support for dynamic link adaptation - possibility to use beamforming; - support for both dynamic and semi-static resource allocation; - support for UE discontinuous reception (DRX) to enable UE power saving; - Support for MBMS transmission. NOTE: The possibility to use slow power control depends on the physical layer. Paging Channel (PCH) characterised by: - support for UE discontinuous reception (DRX) to enable UE power saving (DRX cycle is indicated by the network to the UE); - Requirement to be broadcast in the entire coverage area of the cell; - mapped to physical resources which can be used dynamically also for traffic/other control channels. Multicast Channel (MCH) characterised by: - requirement to be broadcast in the entire coverage area of the cell; - support for MBSFN combining of MBMS transmission on multiple cells; - support for semi-static resource allocation e.g. with a time frame of a long cyclic prefix. Physical Channels Control Related Information: CFI – Control Format Indicator is transmitted in PCFICH HI - HARQ Indicator is transmitted in PHICH DCI – Down Link Control Indicator is transmitted in PDCCH UCI – Uplink Control Information sent on PUCCH/PUSCH
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Physical Channels LTE vs. HSPA LTE PDCCH Physical Downlink Control Channel DL Support: - Allocated DL resources - Modulation Scheme - HARQ info - Transport Format - C-RNTI - Paging Indicators UL Support: - UL Grants with specific allocation of resources PCFICH Physical Control Format Indicator Channel PHICH Physical HARQ ACK/NAK Indicator Channel PDSCH Physical Downlink Shared Channel HSPA E-HICH E-RGCH HS-SCCH E-AGCH HS-PDSCH Downlink Control Channels Operation Support Support for DL Operation z PDCCH transmits information about Resource allocation, HARQ info, Transport format, and implicitly the RNTI for the DL transmission. Similar to HS-SSCH functionalities in HSDPA. z In support of MIMO, there is also some additional information transmitted: 1) The codebook entry, and 2) The transmission rank of the following DL packet. Support for UL Operation z PDCCH can also transmit scheduling grants to the UE. In LTE there is a need to explicitly signal the UL granted resources differently than HSPA (CDMA-based) where only Allowed Power levels are granted. Multiple UEs cannot simultaneously access same subcarriers in an uncontrolled manner. The scheduling grants in HSUPA are managed through E-AGCH and the E-RGCH. z PDCCH has many functionalities and not all of them are used at the same time. Hence, PDCCH requires flexibility with regard to possible configurations. This results in a variable size of the PDCCH and requires an additional channel to inform the UE of a specific configuration. The PCFICH signals how many OFDM symbols (0-3) are occupied by the PDCCH. Support for UL HARQ PHICH sends acknowledgments on DL for UL UE transmitted data. Similar functionality as E-HICH in HSPA. Additional Physical Channels z Physical Broadcast Channel (PBCH) – Carrying part of BCH z Physical Multicast Channel (PMCH) – Carrying MCH (MBSFN multicast) Signals z Reference Signal (RS) (a.k.a Pilots) z Synchronization signals – Primary Synchronization Signal (PSC) – Secondary Synchronization Signal (SSC)
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Synchronization Signals (SCH) Used for Initial System Acquisition • Time/frequency synchronization – Carrier frequency determination – OFDM symbol/subframe/frame timing • Cell ID determination (504 Possible cell IDs) – Cell-IDs are grouped into 168 unique physical- layer cell-identity groups, each group contains 3 unique IDs (168*3 = 504) Transmitted in • Time: subframe 0 and 5 in every radio-frame • Frequency: middle 1.08MHz (6 RBs) Primary synchronization signal (TX on P-SCH) • Provides the cell ID within the cell ID group (1 of 3) • Transmitted in last OFDM symbol of subframes 0 and 5 (provides sub-frame timing) Secondary synchronization signal (TX on S-SCH) • Provides the 168 cell ID group information • M-sequences with scrambling (different “generation” method for SF0 and SF5, provides frame timing) PDSCH PDCCH 6-100 RBs 6 RBs 6x180KHz=1.08MHz PDSCH PDSCH PCFICH PHICH PDCCH S-SCH P-SCH Cell ID Determination using P-SCH and S-SCH Signals There are 504 unique physical-layer cell identities. The physical-layer cell identities are grouped into 168 unique physical-layer cell- identity groups, each group containing 3 unique identities (168*3 = 504) . The grouping is such that each physical-layer cell identity is part of one and only one physical-layer cell-identity group. A physical-layer cell identity is thus uniquely defined by a number in the range of 0 to 167, representing the physical-layer cell-identity group, and a number in the range of 0 to 2, representing the physical-layer identity within the physical-layer cell-identity group. Acquisition Procedure z The initial cell search begins after the UE is switched on. At this time the UE does not know anything about the cells around it and it begins to look for strong cells in the DL band. z Once the UE has found a good candidate with strong 72 subcarriers (6x12) that might carry the synchronization sequences and the BCH, the UE performs a rough frequency synchronization. z The UE looks for the Primary Synchronization Channel (P-SCH). Once it has found it, it knows the exact carrier frequency and the timing of the slot 0 or 10. By trial and error, the UE also knows the CP configuration. z During the previous process, the UE also performed the first step to find the Physical Layer cell ID. Each of the 3 P-SCH sequences is linked to one group member of the 168 different cell ID groups. z The next step is to detect the S-SCH. The SCH is transmitted 1 OFDM symbol before the P-SCH. Once S-SCH is detected, the radio frame and the Physical Layer cell ID are perfectly known. z The UE is ready to read BCH at this time and can also read the PLMN ID from the system information on the BCCH. z UE registers in the cell. Additional information about Synchronization Sequences Primary Synchronization Signal uses: - Frequency domain Zadoff-Chu sequence of length 62 Secondary Synchronization Signal uses: - Interleaved concatenation of two length-31 binary sequences. The concatenated sequence is scrambled with a scrambling sequence given by the primary synchronization signal. - The combination of the two length-31 sequences defining the secondary synchronization signal differs between subframe 0 and subframe 5. according tothe method of interleaving (This difference helps the UE to identify the start of a new frame)
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Broadcast Channel (PBCH) Carries the Broadcast Transport Channel • Overall DL transmission bandwidth • Number of transmit antennas • DL-RS Transmit Power • System Frame Number, etc Transmitted in • Time: subframe 0 in every radio-frame – 4 OFDM symbols in the subframe • Frequency: middle 1.08MHz (6 RBs) TTI = 40 ms • Transmitted in 4 bursts at a very low data rate Transmission such that • Every burst is self-decodable • CRC check uniquely determines the 40ms PBCH TTI boundary PDSCH PDCCH 6-100 RBs 6 RBs 6x180KHz=1.08MHz PDSCH PDSCH PCFICH PHICH PDCCH S-SCH P-SCH PBCH
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Control Format Indicator (PCFICH) Used for Signaling the PDCCH control region: • 1, 2 or 3 OFDM symbols for overall TX BW > 10 RBs • Control region quantized to full OFDM symbols – Control and data do not occur in same OFDM symbol Transmitted in: • Time: 1st OFDM symbol of all subframes • Frequency: spanning the entire system band – 4 REGs Æ 16 REs – Mapping depending on Cell ID Reference Signal Embedded OFDM Symbols 1 ms 5 ms 10 ms subframe 0 1 2 3 4 5 6 7 8 9 Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Downlink Control Channel (PDCCH) Used for: • DL/UL Resource Assignments • Multi-user Transmit Power Control (TPC) commands • Paging indicators Different PDCCH formats are defined: • 1-3 OFDM symbols in a sub-frame • PCFICH using the first OFDM symbol of each subframe informs PDCCH specific format PDCCHs are constructed as follows • CCE is defined as a unit of 36 REs • A PDCCH instance is constructed as 1, 2, 4 or 8 CCEs Reference Signal Embedded OFDM Symbols 1 ms 5 ms 10 ms subframe 0 1 2 3 4 5 6 7 8 9 PDCCH Carries DCI – Downlink Control Information z Uplink assignments: – RB assignment, transport block size, retransmission sequence number, power control command, cyclic shift of DM RS for SDMA, etc. z Downlink assignments: – RB assignment, transport block size, HARQ process number, Redundancy Version index, Uplink power control command z Uplink Power Control Commands z Paging Indicator L1/L2 control channel for: z DL scheduling, including: – Regular unicast data – Scheduling of Paging messages ‹ Acting as a “paging indicator” – Scheduling of SIBs – Scheduling of random access responses z UL grants, including: – Regular unicast data – Requests for aperiodic CQI reports z Multi-user TPC commands: – TPC commands for PUCCH or PUSCH for multiple UEs
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Downlink Shared Channel (PDSCH) Used to transmit DL packet data • One Transport Block transmission per UE’s code word per subframe • A common MCS per code word per UE across all allocated RBs – Independent MCS for two code words per UE • 7 PDSCH TX modes Mapping to Resource Blocks (RBs) • Mapping for a particular transmit antenna port shall be in increasing order of: – First the frequency index and then the time index, starting with the first slot in a subframe. Reference Signal Embedded OFDM Symbols 1 ms 5 ms 10 ms subframe 0 1 2 3 4 5 6 7 8 9 Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical HARQ Indicator PHICH Used for ACK/NAK of UL-SCH transmissions Transmitted in • Time – Normal duration: 1st OFDM symbol – Extended duration: Over 2 or 3 OFDM symbols • Frequency – Spanning all system bandwidth – Mapping depending on Cell ID FDM multiplexed with other DL control channels Support of CDM multiplexing of multiple PHICHs • PHICHs mapped to same resources constitute a PHICH group. • Coding: ACK bit repeated 3 times before “spreading” • Spreading of coded bits using Hadamard codes – SF = 4 for normal CP (results in 12 RE) – SF = 2 for extended CP (results in 6 RE) Reference Signal Embedded OFDM Symbols 1 ms 5 ms 10 ms subframe 0 1 2 3 4 5 6 7 8 9 Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL Reference Signals: 1 TX Antenna DL RS transmitted on 2 OFDM symbols every slot • 6 subcarrier spacing subcarrier subcarrier RB Cell-specific DL Reference Signal (Common Pilots, FS1 and FS2) z Time and Frequency resource allocations: – Allocated on a per Antenna port basis: {0, 1, 2, 3, 4} physical antenna ports – Antenna 0 and 1 transmitted on 2 OFDM symbols every slot ‹ 6 subcarrier spacing and 2x staggering (45 kHz freq sampling) – Antenna 2 and 3 transmitted on 1 OFDM symbol in every slot ‹ 6 subcarrier spacing with 2x staggering across slots – Same frequency spacing for normal and extended CP numerologies
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL Reference Signals: 2 TX Antenna subcarrier subcarrier RB Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL Reference Signals: 4 TX Antenna Overheads Normal CP Ext CP 1 Tx antenna 4.76% 5.56% 2 Tx antenna 9.52% 11.11% 4 Tx antenna 14.29% 15.87% subcarrier subcarrier RB Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Transmission – An Example Example of Frame Structure Type 1 (extended CP) transmission 0 PCFICH PHICH PDCCH RS PDSCH Physical Resource Block (PRB) 2 1 3 Frequency Time Slot Sub Frame Downlink Transmission – An Example The slide shows how a subframe FS1 (extended CP) ends up being transmitted. Observe the first OFDM symbol cell-specific reference signal, PCFICH, informing the assigned UEs of the corresponding PDCCH format. Also PDCCH is transmitted in the first 1-3 OFDM symbols carrying resource allocation and MCS to the corresponding allocated UEs.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section Overview • E-UTRA DL Channelization Hierarchy and Mapping • Downlink Physical Channel Resource Allocations • DL Operation Procedures (Link Adaptation) • DL Transmission Chain Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL Operation Highlights: Similarities to HSPA • Shared Channel Operation • CDS (Channel Dependent Scheduling) –Requires Channel Quality Information (CQI) sent on the UL –Requires Pre-coding and Rank information sent on the UL for MIMO • AMC (Adaptive Modulation and Coding) –Requires informing the UE about allocated Resources –Requires informing the UE about Modulation and Coding Schemes (MCS) • HARQ (Hybrid ARQ) –Uses Asynchronous adaptive retransmissions –Uses Synchronous ACK/NAKs –Requires ACK/NAK sent on the UL • DL Modulation: QPSK, 16-QAM, 64-QAM Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION • Multiple Access Dimensions: • DL Scheduler: –Assigns Time/Frequency resources, rather than Time/Code resources –May coordinate with neighbor Base Stations for interference management. • DL Reference Signals (Pilots): –Have fixed time duration and frequency sub-band allocations. • ARQ runs at E-NodeB –ARQ architecture is conceptually similar to HSPA. (It supports TM, UM, and AM modes and retransmissions are based on status reports.) –Optional HARQ assisted ARQ operation is possible in LTE. • Multiple PDSCH Tx Modes - Requires different Channel Quality Reporting, acknowledging and scheduling mechanisms DL Operation Highlights: Differences from HSPA LTE HSPA (R7) Time (TDMA) Frequency (OFDMA) Space (SU-MIMO, SDMA/MU-MIMO) Time (TDMA) Code (CFDMA) Space (SU-MIMO) Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Data Transfer (1 of 3): Functionality Split across Layers PDCP (ROHC, Security) HSPA (DL) Logical Channels MAC-d Flows Transport Channels Packets from GGSN RLC (ARQ) MAC-d HARQ Multiplexing Scheduling & Priority Handling Physical Layer RNC Node B MAC-hs Radio Bearers Iu Iterface HS-DSCH HS-PDSCH Downlink Data Transfer: Functionality Split Across Layers HARQ Principles (within MAC Layer): z N-process Stop-And-Wait, Asynchronous adaptive HARQ z Uplink ACK/NAKs are sent on PUCCH or PUSCH. z PDCCH signals the HARQ process number and if it is a transmission or retransmission. z Retransmissions are always scheduled through PDCCH. ARQ Principles (within RLC Layer): z ARQ retransmits RLC PDUs or RLC PDU segments. z ARQ retransmissions are based on RLC status reports and optionally ARQ/HARQ interactions. z Polling for RLC status report is used when needed by RLC. ARQ/HARQ Interaction: z Optional HARQ assisted ARQ operation z ARQ uses knowledge from the HARQ about transmission failure status and RLC retransmission and re-segmentation can be initiated.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Data Transfer (2 of 3) Functionality split across physical layer • Max Code Words: 2 – 1 Code Word for rank 1 Transmission – 2 Code Words for rank 2/3/4 Transmissions • Layer Mapping: Fixed mapping between code words to layers • Max Tx Antennas: 4 – Potentially up to 4 layers • Pre-coding: – Code book based precoding • Channel Dependant precoding and Rank Indicator reported by the UE for closed loop MIMO Mapper OFDM signal generation Layer Mapper Scrambling Precoding Modulation Mapper Modulation Mapper OFDM Mapper OFDM signal generation Scrambling code words antenna ports OFDM layers •DL Multiple Antenna Transmission: Generalized PDSCH TX A brief description of the generalized transmission blocks z scrambling of coded bits in each of the code words to be transmitted on a physical channel z modulation of scrambled bits to generate complex-valued modulation symbols z mapping of the complex-valued modulation symbols onto one or several transmission layers z precoding of the complex-valued modulation symbols on each layer for transmission on the antenna ports z mapping of complex-valued modulation symbols for each antenna port to resource elements z generation of complex-valued time-domain OFDM signal for each antenna port Multiple Antenna Transmission/Reception (MIMO) schemes were inherent in the design of E-UTRA (R8) MIMO classifications from the Number of Code Words Perspective: Single Code Word (SCW) -> Use one Channel Coder per user Multiple Code Word (MCW) -> Use Multiple Channel Coders per user MCW offers better performance relative to SCW at the expense of additional complexity and signaling LTE employs MCW (up to two Code Words) for MIMO transmissions. Advantages and disadvantages of using either SCW or MCW The SCW scheme has simple HARQ identical to SISO, simple ACK/NACK messaging identical to SISO, and low complexity MMSE receiver. The drawback of SCW is that it is not capacity achieving and suffers from a throughput loss in low rank channels, such as, spatially correlated channels or LOS channels with high Rician K-factor. MCW allows Per Antenna Rate Control (PARC) and Successive Interference Cancellation (SIC). the MCW transmission with a successive interference cancellation (SIC) receiver is capacity achieving and hence optimal in performance. A successive interference cancellation (SIC) receiver is used to decouple the M layers providing higher throughput and more tolerance to spatial correlation. However, MCW with SIC comes at the cost of increased signaling overhead, receiver complexity and memory requirements. The signaling overhead for the Reverse Link and Forward Link Control channels are larger than a SCW transmission since the channel quality CQI, coding and modulation, and acknowledgements have to be signaled for each MIMO layer. Furthermore, the SIC receiver memory requirements are high since the MIMO channel and received signals have to be stored for all HARQ transmissions. The receiver processing is more complicated and bursty since lower layers can not be decoded until the upper layers are decoded. M.M. Mao, et.al, “Multi-Antenna Techniques in Ultra Mobile Broadband Communication Systems,” IEEE Communications Networks and Services Conference, 2008
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Mode 1: Single-antenna port; port 0 • Transmissions using a single Tx antenna at eNodeB (“conventional” approach) Mode 2: Transmit diversity • transmissions using Alamouti alike transmit diversity schemes Mode 3: Open-loop spatial multiplexing • transmissions using spatial multiplexing (up to two codewords), but no PMI feedback • Also exploits Cyclic Delay Diversity (CDD) transmissions Mode 4: Closed-loop spatial multiplexing • transmissions in closed loop SU-MIMO configuration (PMI and RI feedback) • Up to two codewords, 4 layers, 4 antennas Mode 5: Multi-user MIMO • Closed loop MU-MIMO or Space Division Multiple Access (SDMA) configuration • Different users can use same time/frequency resources in different location within a cell Mode 6: Closed-loop Rank=1 precoding • Same as Mode 4 without the need of Rank reports Mode 7: Single-antenna port; port 5 • Same as Mode 1 using UE-specific Reference Signals PDSCH TX mode is signaled using different DCI Types over PDCCH Downlink Data Transfer (3 of 3) PDSCH Multiple Transmission Modes A UE not configured to receive PDSCH data transmissions based on one of the transmission modes may receive PDSCH data transmissions with DCI format 1A signalled by a PDCCH in its UE specific search spaces or the common search spaces. -Multi-antenna transmission with 2 and 4 transmit antennas is supported. -The maximum number of codeword is two irrespective to the number of antennas with fixed mapping between code words to layers. -Spatial division multiplexing (SDM) of multiple modulation symbol streams to a single UE using the same time-frequency resource, also referred to as Single-User MIMO (SU-MIMO) is supported. When a MIMO channel is solely assigned to a single UE, it is known as SU-MIMO. -Spatial division multiplexing of modulation symbol streams to different UEs using the same time- frequency resource, also referred to as MU-MIMO, is also supported. There is semi-static switching between SU-MIMO and MU-MIMO per UE.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-NodeB E-NodeB MME X1 PDSCH multiple TX modes PDSCH Physical Downlink Shared Channel PDCCH Physical Downlink Control Channel PFICH Physical Format Indicator Channel PUCCH Physical Uplink Control Channel DL Scheduled Operation Overview PFICH PDCCH PUCCH or PUSCH IP Network X2 1. UE reports CQI (Channel Quality Indicator), PMI (Pre-coding Matrix Index) and RI (Rank Indicator) in PUCCH (or PUSCH if there is UL traffic) 2. Scheduler at E-NodeB dynamically allocates resources to UE: - UE reads PCFICH every subframe and finds out the number of OFDM symbols occupied by PDCCH - UE finds about TX Mode and assigned resources (PRB and MCS) reading PDCCH 3. E-NodeB sends user data in PDSCH 4. UE attempts to decode the received packet and sends ACK/NACK using PUCCH (or PUSCH if there is UL traffic) Basic Scheduler Operation: - MAC in eNB includes a dynamic resource scheduler that allocate physical layer resources for the DL-SCH and UL-SCH transport channels - Different schedulers operate on DL-SCH and UL-SCH - The scheduler takes into account the traffic volume and the QoS requirements of each UE and associated radio bearers when sharing resources between UEs - DL Scheduler also assign resources taking into account the radio conditions as identified by the UE through reported measurements - Radio resource allocations can be valid for one or multiple TTIs - Resource assignment consists of physical resource blocks (PRB) and MCS - Allocations for time periods longer than one TTI might also require additional information (allocation time, allocation repetition factor…). - In the downlink, E-UTRAN can dynamically allocate resources (PRBs and MCS) to UEs at each TTI via the C-RNTI on L1/L2 control channel(s) - A UE always monitors L1/L2 control channel(s) in order to find possible allocation when its downlink reception is enabled (activity governed by DRX) - In addition, E-UTRAN can allocate persistent downlink resources for the first HARQ transmissions to UEs. When required, retransmissions are explicitly signalled via the L1/L2 control channel(s). - In the sub-frames where the UE has persistent resource, if the UE cannot find its C-RNTI on the L1/L2 control channel(s), a downlink transmission according to the persistent allocation that the UE has been assigned in the TTI is assumed. - Otherwise, in the sub-frames where the UE has persistent resource, if the UE finds its C-RNTI on the L1/L2 control channel(s), the L1/L2 control channel allocation overrides the persistent allocation for that TTI and the UE does not decode the persistent resources.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION CQI/PMI/RI Reporting Overview E-NodeB PUSCH PUCCH Reporting on PUSCH - Aperiodic Reports -Wideband CQI (multiple-PMI per subband) -UE Selected Subband CQI (No-PMI, Multiple-PMI) -Higher Layer Configured Subband CQI (No-PMI, Single-PMI) -Frequency selective/non-selective scheduling Reporting on PUCCH -Periodic Reports -Wideband CQI (No-PMI, Single-PMI) -UE Selected Subband CQI (No-PMI, Single-PMI) -Frequency selective/non-selective scheduling Aperiodic CQI/PMI/RI reporting is defined by the following characteristics: - The report is scheduled by the eNB via the PDCCH - Transmitted together with uplink data on PUSCH - From the frequency span perspective these reports can be: - Frequency selective: UE Selected Subband CQI and Higher Layer Configured Subband CQI - Frequency non-selective: Wideband CQI reports - When a CQI report is transmitted together with uplink data on PUSCH, it is multiplexed with the transport block by L1 (i.e. the CQI report is not part of the uplink the transport block). Periodic CQI/PMI/RI reporting is defined by the following characteristics: - Periodic CQI reports are sent on PUCCH - From the Frequency span perspective these reports can be: - Frequency selective: UE Selected Subband CQI - Frequency non-selective: Wideband CQI reports A UE can be configured to have both periodic and aperiodic reporting at the same time - In case both periodic and aperiodic reporting occurs in the same subframe, only the aperiodic report is transmitted in that subframe. Observe that both types of reports: Periodic over PUCCH and Aperiodic over PUSCH enable efficient Frequency-Diverse Scheduling (FDS) and Frequency-Selective Scheduling (FSS). Frequency-diverse (non-selective) scheduling (FDS)
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Dynamic Scheduling: E-UTRAN dynamically allocates resources (PRBs and MCS) to UEs at each TTI via the C-RNTI on PDCCH(s) • UE monitors the PDCCH(s) in order to find possible allocation when its downlink reception is enabled (activity governed by DRX when configured) Semi-persistent Scheduling: Initially PDCCH indicates if the DL grant can be implicitly reused in the following TTIs according to the periodicity defined by RRC • RRC defines the periodicity of the semi-persistent DL grant – Characterized by a start frame number, periodicity and packet format (one or more may be defined) • Retransmissions are explicitly signalled via the PDCCH(s). E-UTRA DL Scheduling Principles For persistent assignments z In the sub-frames where the UE has semi-persistent downlink resource, if the UE cannot find its C-RNTI on the PDCCH(s), a downlink transmission according to the semi-persistent allocation that the UE has been assigned in the TTI is assumed. z in the sub-frames where the UE has semi-persistent downlink resource, if the UE finds its C- RNTI on the PDCCH(s), the PDCCH allocation overrides the semi-persistent allocation for that TTI and the UE does not decode the semi-persistent resources.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL ARQ/HARQ Principles and Interaction HARQ Principles (within MAC Layer) • N-process Stop-And-Wait, Asynchronous adaptive HARQ • Uplink ACK/NAKs are sent on PUCCH or PUSCH. • PDCCH signals the HARQ process number and whether it is a transmission or retransmission. • Retransmissions are always scheduled through PDCCH. ARQ Principles (within RLC Layer) • ARQ retransmits RLC PDUs or RLC PDU segments. • ARQ retransmissions are based on RLC status reports and optionally ARQ/HARQ interactions. • Polling for RLC status report is used when needed by RLC. ARQ/HARQ Interaction • Optional HARQ assisted ARQ operation • ARQ uses knowledge from the HARQ about transmission failure status and RLC retransmission and re-segmentation can be initiated. Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION CQI/PMI/RI and ACK/NACKs multiplexing on PUCCH is possible: • Format 2: – CQI/PMI/RI not multiplexed with ACK/NAK • Format 2a/2b – CQI/PMI/RI multiplexed with ACK/NAK (normal CP) • Format 2: – CQI/PMI or RI multiplexed with ACK/NAK (extended CP) ACK/NACK for PDSCH Transmissions The UE shall, upon detection of a PDSCH transmission in subframe n-4 intended for the UE and for which an ACK/NACK shall be provided, transmit the ACK/NACK response in subframe n. ACK/NACKs alone can be delivered PUCCH format 1a and 1b
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 4 SECTION Uplink Channels & Procedures Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section 4 Objectives ¾ Describe channel structure and mapping for UL. ¾ Provide time/frequency SC-FDMA numerology for UL. ¾ Describe physical channel resource allocation for UL. ¾ Describe overall UL operations. Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA UL Channels and Signals Signals • Demodulation Reference Signal (DM-RS) • Sounding Reference Signal (SRS) Control • ACK, CQI, Rank Indicator (RI), Precoding support (PMI) • Scheduling Request (SR) • Single “control” channel - Physical Uplink Control Channel (PUCCH) Data • Unicast data and data + control • Single “data” channel - Physical Uplink Shared Channel (PUSCH) Random access • Preamble sequences in Physical Random Access Channel (PRACH)
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA UL Waveform: SC-FDM • OFDM based UL transmission would lead to higher Peak-to- Average Power Ratio (PAPR) than the SC-FDM (TR25.814 Section 9.2.1.4). • Single Carrier Waveform (SC-FDM or DFT-spread OFDM) – Requires Data and control channels to be multiplexed prior to the DFT operation at the transmitter • “Price” of maintaining Single Carrier Waveform – 32 channel combinations == Multiplexing “rules” » Data, ACK, CQI, SRS, SR » No channel can be transmitted independently of the other • Data and UL Demodulation Pilots (Reference Signals) are TDM In OFDM each sub-carrier carries information from a specific modulation symbol and given the nature of this OFDM signal the PAPR due to the simultaneous transmission of multiple carriers can be significant. In SC-FDM each sub-carrier carries information from all transmitted modulation symbols since the latter are spread by the DFT operation and then mapped to each sub-carrier. This single carrier transmission achieved by an IDFT operation followed by an FFT operation results in a lower PAPR. Careful multiplexing of data and control information is required for SC-FDM transmission.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Uplink Channelization Hierarchy No dedicated transport channels: Focus on “shared” transport channels Dedicated Control/Traffic Common Control UCI Physical Control E-UTRA Uplink Channel Structure TS36.321 Section 4.5 MAC specifications include the details about the mapping of logical channels onto transport channels, and TS36.212 Section 4 about the mapping of transport channels on physical channels. Logical Channels: z Common Control Channel (CCCH) – For Idle Mode (RRC_IDLE) connection establishment (e.g., call setup, registration) z Dedicated Control Channel (DCCH) – For Connected Mode (RRC_CONNECTED) signaling z Dedicated Traffic Channel (DTCH) – For Connected Mode (RRC_CONNECTED) user data traffic Transport Channels: z Random Access Channel (RACH) – Uplink random access z Uplink Shared Channel (UL-SCH) – Signaling and traffic are multiplexed onto UL-SCH Physical Channels: z Physical Random Access Channel (PRACH) z Physical Uplink Control Channel (PUCCH) – For carrying physical control information – Uplink control information (UCI) if PUSCH is not configured z Physical Uplink Shared Channel (PUSCH) – For carrying dedicated control/traffic as well as UCI
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION LTE PUCCH or PUSCH Physical Uplink Control Channel (used to carry Control Information) DL Support: - Channel Quality Information (CQI and/or PMI) - HARQ ACK/NAK - Rank Indication UL Support: - Scheduling request - Buffer Status Report - Power Headroom Report - Transport Format - Uplink HARQ information - C-RNTI MAC Control Element PRACH Physical Random Access Channel PUSCH Physical Uplink Shared Channel (used to carry user data) HSPA E-DPDCH HS-DPCCH PRACH E-DPDCH E-DPCCH Uplink Physical Channels LTE vs. HSPA Uplink Physical Channels LTE vs. HSPA Uplink Control Information (UCI) contains: z Channel Quality Information (Channel Quality Indicator - CQI and/or Precoding Matrix Indicator - PMI) – For HSPA, this is sent on HS-DPCCH. z HARQ-ACK (Acknowledgements) – For HSPA, this is sent on HS-DPCCH. z Rank Indication – For HSPA+, rank information is sent in extended CQI range on HS-DPCCH. z Scheduling Request, Buffer Status Report and Power Headroom Report – For HSPA, scheduling information (SI) is sent in-band on E-DPDCH. z Transport Format and Uplink HARQ Information – For HSPA, the transport format and Uplink HARQ information is sent on E-DPCCH. z C-RNTI MAC Control Element – There is no equivalent information needed in HSPA due to the use of dedicated transport and physical channels. UCI may be mapped onto PUSCH or PUCCH. z PUSCH can carry user data and Uplink Control Information (UCI). z PUCCH carries only the Uplink Control Information (UCI), and is used only when UE is not transmitting PUSCH.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Uplink Reference Signals •Two types of E-UTRA/LTE Uplink Reference Signals: • Demodulation reference signal – Associated with transmission of PUSCH or PUCCH – Purpose: Channel estimation for uplink coherent demodulation/detection of the uplink control and data channels – Transmitted in time/frequency depending on the channel type (PUSCH/PUCCH), format, and cyclic prefix type • Sounding reference signal – Not associated with transmission of PUSCH or PUCCH – Purpose: Uplink channel quality estimation feedback to the uplink scheduler (for Channel Dependent Scheduling) at the e-NodeB – Transmitted in time/frequency depending on the SRS bandwidth and the SRS bandwidth configuration (some rules apply if overlap with PUSCH and PUCCH) Notes •The same set of base sequences is used to generate demodulation and sounding reference signals •The base sequences and the reference signals are derived from Zadoff-Chu sequences •Cyclic shifts can be applied to a base sequence to obtain multiple reference signal sequences
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Uplink Shared Channel (PUSCH) PUSCH Normal Cyclic Prefix Extended Cyclic Prefix Demodulation-RS Embedded SC- FDMA Symbols 1 Subframe = 1 ms PUSCH PUSCH 5 ms 1 Radio Frame = 10 ms Subframe 0 1 2 3 4 5 6 7 8 9 1 Time Slot Frequency Hopping No Frequency Hopping Frequency diversity through hopping Demodulation Reference Signal (DM-RS) l = 0 l = 7 l = 0 l = 6 PUSCH More information can be found in TS36.211. z Details about Demodulation Reference Signal on PUSCH can be found in §5.5.2.1.2. z Details about Demodulation Reference Signal on PUCCH can be found in §5.5.2.2.2. The reference signal sequence shall be multiplied with the amplitude scaling factor and mapped resource elements. The resource element mapping shall be in increasing order of first k (sub- carrier), then l (symbol), and finally the slot number.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION PUSCH Frequency Hopping Demodulation-RS Embedded SC- FDMA Symbols 6-100 RBs 1 Subframe = 1 ms PUSCH PUSCH 5 ms 1 Radio Frame = 10 ms Subframe 0 1 2 3 4 5 6 7 8 9 PUSCH Intra- and Inter- Subframe Hopping 6-100 RBs Inter- Subframe Hopping PUSCH Frequency Hopping More information about PUSCH frequency hopping can be found in TS36.211 §5.3.4.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION PUSCH Transmission UL data transmission • One Transport Block transmission per codeword per subframe Mapping to resource elements • Mapping shall be in increasing order of first the frequency index, then the time index, and finally the slot number (i.e., starting with the first slot in the subframe).
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Uplink Control Channel (PUCCH) Demodulation-RS Embedded SC- FDMA Symbols 6-100 RBs 1 Subframe = 1 ms PUCCH PUSCH 5 ms 1 Radio Frame = 10 ms Subframe 0 1 2 3 4 5 6 7 8 9 PUCCH PUCCH PUCCH PUCCH PUCCH PUCCH PUCCH Frequency Hop at Time Slot Boundary Format 2, 2a, 2b 1 Time Slot Demodulation Reference Signal (DM-RS) PUCCH l = 0 Normal Cyclic Prefix Extended Cyclic Prefix PUCCH Normal Cyclic Prefix Extended Cyclic Prefix 1 Time Slot Format 1, 1a, 1b PUCCH uses one resource block in each of the two slots in a subframe. l = 7 l = 0 l = 7 l = 0 l = 6 l = 0 l = 6 Physical Uplink Control Channel (PUCCH) The physical Uplink control channel, PUCCH, carries Uplink control information (UCI), and is never transmitted simultaneously with the PUSCH from the same UE. A maximum of 4 resource blocks are reserved for PUCCH in this example. The physical resources used for PUCCH depend on parameters given by higher layers. The following combinations of Uplink control information (UCI) are supported on PUCCH: z HARQ-ACK using PUCCH format 1a or 1b z Scheduling request (SR) using PUCCH format 1 z HARQ-ACK and SR using PUCCH format 1a or 1b z CQI/PMI or RI using PUCCH format 2 z CQI/PMI or RI and HARQ-ACK using PUCCH format – 2a or 2b for normal cyclic prefix – 2 for extended cyclic prefix
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION PUCCH – ACK and CQI time ACK CQI
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Sounding Reference Signals (SRS) SRS shall be transmitted at the last symbol of the subframe. PUSCH: • The mapping to resource elements only considers those not used for transmission of reference signals. PUCCH Format 1a and 1b (HARQ-ACK): • One SC-FDMA symbol on PUCCH shall be punctured. PUCCH Format 1 (SR) and 2, 2a, 2b (CQI): • A UE shall not transmit SRS whenever SRS collide with PUCCH format 1 (SR), and 2, 2a and 2b (CQI). Sounding Reference Signals Details about UE sounding procedure can be found in TS36.211 and TS36.213 §8.3. The reference signal sequence shall be multiplied with the amplitude scaling factor and mapped resource elements. The resource element mapping shall be in increasing order of first k, then l, and finally the slot number. There are many FDD sounding reference signal subframe configurations as per TS36.211 §5.5.3.3. The sounding reference signal shall be transmitted at the last symbol of the subframe according to 36.211. A UE shall not transmit SRS whenever SRS and CQI transmissions happen to coincide in the same subframe. A UE shall not transmit SRS whenever SRS and SR transmissions happen to coincide in the same subframe. When a UE is configured by higher layers to support both A/N and SRS transmissions in the same subframe, then the UE shall transmit A/N using a shortened PUCCH format where the A/N symbol corresponding to the SRS location is punctured.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION RA offset PRB n PRACH CP T SEQ T PRACH: • The preamble format determines the length of the Cyclic Prefix and Sequence • FDD has 4 preamble formats (for different cell sizes) and 16 RA slot configurations (for different bandwidth) • The start of Random Access Preamble transmission assumes Timing Advance = 0 except for handover that UE can assume a time difference between current cell and target cell • Each random access preamble occupies a bandwidth corresponding to 6 consecutive resource blocks • The diagram considers RACH structure for FDD PRACH The transmission of a random access preamble, if triggered by the MAC layer, is restricted to certain time and frequency resources. These resources are enumerated in increasing order of the subframe number within the radio frame and the physical resource blocks in the frequency domain such that index 0 correspond to the lowest numbered physical resource block and subframe within the radio frame. Note that cyclic prefix is extended to cope with large delay uncertainty (for different cell sizes). More information can be found in TS36.211 Section 5.7. Preamble format CP T SEQ T 0 s 3168 T ⋅ s 24576 T ⋅ 1 s 21024 T ⋅ s 24576 T ⋅ 2 s 6240 T ⋅ s 24576 2 T ⋅ ⋅ 3 s 21024 T ⋅ s 24576 2 T ⋅ ⋅ 4 (frame structure type 2 only) s 448 T ⋅ s 4096 T ⋅
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section Overview • SC-FDMA in E-UTRA Uplink Waveform • E-UTRA UL Channelization Hierarchy and Mapping • UL Physical Channels Resource Allocation • UL Operation Procedures Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Uplink Operation Highlights • Link Adaptation (CDS – Channel Dependent Scheduling) – Adaptive transmission Bandwidth – Adaptive Modulation and Channel Coding Rate (AMC) – Meets QoS requirements • UL Power Control – Intra-cell power control: the power spectral density of the Uplink transmissions can be influenced by the eNB. • UL Timing Control – Objective is to compensate for propagation delay and thus time-align the transmissions from different UEs with the receiver window of the eNB. – The timing advance is derived from the UL received timing and sent by the eNB to the UE. UE uses this information to advance/delay its timings of transmissions to the eNB. • Random Access procedure E-UTRA UL Operation Highlights Uplink link adaptation is used to guarantee the required minimum transmission performance of each UE such as the user data rate, packet error rate, and latency, while maximizing system throughput. Three types of link adaptation are performed according to the channel conditions, the UE capability such as the maximum transmission power and maximum transmission bandwidth, etc., and the required QoS such as the data rate, latency, and packet error rate, etc. Three link adaptation methods are as follows: z Adaptive transmission bandwidth z Transmission power control z Adaptive modulation and channel coding rate Uplink Power control: Intra-cell power control: the power spectral density of the Uplink transmissions can be influenced by the eNB. Uplink timing control z The timing advance is derived from the UL received timing and sent by the eNB to the UE. The UE uses this to advance/delay its timings of transmissions to the eNB to compensate for propagation delay and thus time-align the transmissions from different UEs with the receiver window of the eNB. z The timing advance command is on a per need basis with a granularity in the step size of 0.52 μs (16×Ts).
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Uplink Operation Highlights (continued) Link Adaptation differences from HSPA: • Shared Channel Operation – Dedicated logical channels are mapped onto shared transport/physical channels • UL Multiple Access Dimensions: – frequency/time/space in LTE; code/time in HSPA • UL scheduler – Uplink time/frequency resources are monitored/managed at the E-NodeB. – HSPA, in contrast, monitors/manages Uplink Interference (Rise Over Thermal). – LTE scheduler assigns UL Time/Frequency resources, rather than UL TX Traffic/Pilot Ratios as in HSPA. – As in HSPA, Uplink scheduling is based on Scheduling Requests (SR), Buffer Status Report (BSR), and Power Headroom Reports (PHR). – It may coordinate with neighbor Base Stations for Interference management • Requires UL timing control to keep UL orthogonal E-UTRA UL Operation Highlights (continued) From TS36.201, transmissions with multiple input and multiple output antennas (MIMO) are supported with configurations in the Downlink with two or four transmit antennas and two or four receive antennas, which allow for multi-layer transmissions with up to four streams. Multi-user MIMO, i.e., allocation of different streams to different users, is supported in both UL and DL.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION • UE sends SR (Scheduling Request – part of Uplink Control Information), BSR (Buffer Status Report) and PHR (Power Headroom Report) on PUCCH (or starts random access if no PUCCH is configured). • Scheduler at E-NodeB dynamically allocates UL resources to UE: – Grant is assigned to UE on PDCCH. – Assigned resources (PRB and MCS) are communicated to the UE. • UE sends user data on PUSCH. • If E-Node B decodes the Uplink data successfully, it changes the New Data Indicator (NDI) on PDCCH, and/or sends ACK/NAKs on PHICH. PUCCH Physical Uplink Control Channel PDCCH Physical Downlink Control Channel PUSCH Physical Uplink Shared Channel PHICH Physical HARQ ACK/NAK Indicator Channel E-NodeB E-NodeB MME X1 PUSCH PHICH PUCCH IP Network X2 PDCCH E-UTRA UL Scheduled Operation (Link Adaptation) E-UTRA Uplink Scheduled Operation The following information is transmitted by means of the Downlink Control Information (DCI) format 0 on PDCCH for the scheduling of PUSCH: z Flag for format0/format1A differentiation z Hopping flag z Resource block assignment and hopping resource allocation z Modulation and coding scheme and redundancy version z New Data Indicator (NDI) z TPC command for scheduled PUSCH z Cyclic shift for DM RS z CQI request – 1 bit The details about grant value and its relationship to PUSCH power can be found in TS36.213 § 5.1.1.1. The UE ACK-NAK procedure is described in TS36.213 § 8.3. New Data Indicator (NDI) can be found in the Downlink Control Information (DCI) format 0 on PDCCH together with the Uplink scheduling assignment. HARQ ACK/NAKs are sent on the Downlink PHICH. Retransmissions shall be needed if the NDI has not changed or if PDCCH is not detected. Uplink Scheduling at E-Node B is based on: z Serving Cell Uplink Noise Rise (Rise-over-Thermal) z Overload Indicators from other E-Node Bs z UE Scheduling Requests (SR) z UE Buffer Status (BSR) z UE Power Headroom Report (PHR) z UE Capabilities
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA User-Plane UL Data Transfer Functionality Split across Layers MAC-es/e Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION • UE transmits PUCCH or PUSCH. • Serving E-NodeB monitors link quality and takes into account the overload indicators (over X2) from neighbor cells. • Serving E-NodeB sends Transmit Power Control commands (TPC) as part of Downlink Control Information (DCI) on PDCCH. • UE adjusts transmit power levels of PUCCH or PUSCH. • Go back to 1. PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel PDCCH Physical Downlink Control Channel E-NodeB E-NodeB MME X1 PUSCH PUCCH IP Network X2 PDCCH PDSCH Overload Indicator Single Serving Cell No Soft Handover No Macro-diversity E-UTRA UL Closed Loop Power Control E-UTRA Uplink Closed Loop Power Control Uplink power control determines the average power over a DFT-SOFDM symbol in which the physical channel is transmitted. Uplink power control controls the transmit power of the different Uplink physical channels. A cell wide overload indicator (OI) is exchanged over X2 for inter-cell power control. DCI format 0 provides two bits of TPC command for PUSCH. DCI format 1, 1a and 2 provides two bits of TPC command for PUCCH. DCI format 3 is used for the transmission of TPC commands for PUCCH and PUSCH with 2-bit power adjustments. DCI format 3A is used for the transmission of TPC commands for PUCCH and PUSCH with single bit power adjustments.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Random Access •Random Access can be triggered by: • PDCCH order (i.e., handover) • UE MAC sublayer (i.e., initial access) •Two types of Random Access: • Synchronized: – The PDCCH order or RRC optionally indicate a Random Access Preamble and PRACH resource – When Random Access Preamble and PRACH resource are explicitly signaled, it is contention free • Unsynchronized – UE selects a Random Access Preamble and PRACH resource ‹ Select one of the two groups of Random Access Preambles configured by RRC ‹ Randomly select a Random Access Preamble within the selected group ‹ Contention resolution is needed E-UTRA Random Access More information can be found in TS36.321 Section 5.1.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Synchronized Random Access •The E-UTRA Random Access procedure is specified mainly in the MAC layer only! Preamble Initial Received Target Power Power Ramp Step Preamble Received Target Power … MAC (Layer 2) PHY (Layer 1) Power Ramp Step Preamble Transmission Counter 1 2 3 … Time Random Access Response (on PDCCH assoc with RA-RNTI) TTI Window + Backoff Random Access Preamble Identifier Match Random Access procedure successfully completed [TTI Window] ≤ Preamble Trans Max • Timing Advance / Alignment (TA) value • Uplink grant value • Temporary C- RNTI E-UTRA Synchronized Random Access Before the random access procedure can be initiated, the following information is assumed to be available: z - the available set of PRACH resources for the transmission of the Random Access Preamble and their corresponding RA-RNTIs. z - the groups of Random Access Preambles and the set of available Random Access Preambles in each group. – There are 64 preambles available in each cell. z - the thresholds required for selecting one of the two groups of Random Access Preambles. z - the parameters required to derive the TTI window [RA_Window_Begin – RA_Window_End]. z - the power-ramping factor POWER_RAMP_STEP. z - the parameter PREAMBLE_TRANS_MAX [integer > 0]. z - the initial preamble power PREAMBLE_ INITIAL_RECEIVED_TARGET_POWER. z - the parameter Maximum number of Message3 HARQ transmissions. Note that the diagram above is only for illustration of the random access sequence, and the exact transmission timing of the random access preamble should be determined according to the selection of the PRACH resources (specified in time and frequency domain) as per TS36.321 Section 5.1.2. E-UTRA Random Access Response More information can be found in TS36.321 Section 5.1.4. Once the Random Access Preamble is transmitted, the UE shall monitor the PDCCH associated with the RA-RNTI defined below in the TTI window [RA_WINDOW_BEGIN—RA_WINDOW_END] for Random Access Responses identified by the RA-RNTI.
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Cell Switching (1/2) Only one serving cell per UE ƒ Same for UL and DL »UE does not receive DL data or UL ACKs from multiple cells ƒ UE cannot transmit to multiple cells with single Tx chain in asynchronous deployments »Single carrier waveform in uplink L2 handover ƒ Network based » UE assisted ƒ UE based »UE performs HO autonomously
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Comments/Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 5 SECTION What is Next? Notes
Long Term Evolution (LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION LTE Advanced LTE Targets (3GPP TS25.913) LTE Advanced Targets (3GPP TR36.913) Latency • U-plane latency: < 5 ms (unloaded) • C-plane latency: ƒ < 100 ms from Idle to Active ƒ < 50 ms from Dormant to Active Data Rate • DL peak rate: ƒ 100 Mbps (20 MHz) • UL peak rate: ƒ 50 Mbps (20 MHz) Latency •U-plane latency: lower than LTE •C-plane latency: ƒ < 50 ms from Idle to Active ƒ < 10 ms from Dormant to Active Data Rate • DL peak rate: ƒ Low mobility: 1 Gbps ƒ High mobility: 100 Mbps • UL peak rate: 500 Mbps Spectrum Efficiency • DL: 3-4 X 3GPP Release 6 • UL: 2-3 X 3GPP Release 6 Scalable Bandwidth 1.25 to 20 MHz Extend Bandwidth Scalability up to 100 MHz Spectrum Efficiency • DL: Peak: 30 bps/Hz ƒ Avg: 2.4 - 3.7 bps/Hz ƒ Cell Edge: 0.07 – 0.12 bps/Hz • UL: Peak: 15 bps / Hz ƒ Avg: 1.2 - 2.0 bps/Hz ƒ Cell Edge: 0.04 – 0.07 bps/Hz June 2008 LTE Advanced LTE requirements are described in 3GPP TR25.913, while LTE Advanced requirements are described in 3GPP TR36.913. Note that all minimum requirements for UTRA found in TR25.913 would apply to E-UTRA / LTE if not described in TR36.913.

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499198466-LTE-Fundamentals-FinalMerged-PB5.pdf

  • 1.
    MAY CONTAIN U.S.AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Long Term Evolution (LTE/FDD) Fundamentals Long Term Evolution (LTE/FDD) Fundamentals Student Guide 80-W1738-1 Rev B
  • 2.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION About Qualcomm University Qualcomm University (“QU”) offers the advanced technology training solutions you need to stay on the cutting edge of wireless technology. Visit the QU website for more information about individual training products, international training centers, and distance learning opportunities, along with a complete list of classes—all developed by QUALCOMM Incorporated, the pioneers of CDMA. Qualcomm University: www.qualcommuniversity.com QUALCOMM Incorporated: www.qualcomm.com Notes iii
  • 3.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Where Can I Learn More? Want to learn more? Qualcomm University offers additional in-depth technical training related to this course. To view a map of all current training offerings or get more information, go to: www.qualcommuniversity.com Notes iv
  • 4.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION vii Acronyms and Abbreviations 16-QAM 16-Quadrature Amplitude Modulation 3G 3rd G eneration 3GPP 3rd Generation Partnership Project AAA Authentication, Authorization and Accounting ACK Acknowledgment AIPN All-IP Network AM Acknowledged Mode AMBR Aggregate Maximum Bit Rate AMC Adaptive Modulation and Coding AN Access Network A/N ACK/NAK ARQ Automatic Repeat Request AS Access Stratum AT Access Terminal BCCH Broadcast Control Channel BCH Broadcast Channel BSR Buffer Status Report BW BandWidth CCCH Common Control Channel CCE Carrier Class Ethernet CDMA Code Division Multiple Access CDS Channel Dependent Scheduling CN Core Network CP Cyclic Prefix CQI Channel Quality Indicator CRC Cyclic Redundancy Check C-RNTI Cell Radio Network Temporary Identifier CS Circuit Switched CW Code Word DCCH Dedicated Control Channel DCI Downlink Control Information DL Downlink DL-SCH Downlink Shared Channel DM Demodulation DM-RS Demodulation Reference Signal DRX Discontinuous Transmission DTCH Dedicated Traffic Channel E-AGCH Enhanced Absolute Granting Channel E-DPCCH Enhanced Dedicated Physical Control Channel E-DPDCH Enhanced Dedicated Physical Data Channel E-HICH Enhanced Hybrid Indicator Channel eNB Evolved Node B EPC Evolved Packet Core EPS Evolved Packet System; LTE and SAE
  • 5.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION viii E-RGCH Enhanced Relative Granting Channel E-UTRA Evolved UMTS Terrestrial Radio Access; PHY aspects E-UTRAN Evolved UMTS Terrestrial Radio Access Network; MAC / L2 / L3 aspects FD Full-Duplex FDD Frequency Division Duplex FDM Frequency Division Multiplexing FDMA Frequency Division Multiple Access FFT Fast Fourier Transform FL Forward Link GERAN GSM/EDGE Radio Access Network GGSN GPRS Gateway Support Node GPRS General Packet Radio Service GSM Global System for Mobiles (European standard) GW Gateway HA Home Agent HARQ Hybrid ARQ HD Half-Duplex HLR Home Location Register HO Handover HRPD High Rate Packet Data HSDPA High Speed Downlink Packet Access HS-DPCCH High Speed Dedicated Control Channel HSPA High-Speed Packet Access HSPA+ High-Speed Packet Access evolved or enhanced HS-PDSCH High Speed Physical Downlink Shared Channel HSS Home Subscriber Service HS-SCCH High Speed Shared Control Channel HSUPA High Speed Uplink Packet Access IDFT Inverse Discrete Fourier Transform IFDMA Interleaved Frequency Division Multiple Access IMS IP Multimedia Subsystem IP Internet Protocol L1 Layer 1 L2 Layer 2 LAN Local Area Networks LFDM Localized Frequency Division Multiplexing LFDMA Localized Frequency Division Multiple Access LTE Long Term Evolution MAC Medium Access Control MBMS Multimedia Broadcast Multicast Service MBSFN Multimedia Broadcast over a Single Frequency Network MCCH Multicast Control Channel MCH Multicast Channel MCS Modulation and Coding Schemes MIMO Multiple-Input-Multiple-Output MME Mobility Management Entity
  • 6.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Outline 1. Network Architecture: Evolution & Protocols 2. E-UTRA Essentials 3. Downlink Channels and Procedures 4. Uplink Channels and Procedures 5. What is Next? Notes
  • 7.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 1 SECTION Network Architecture: Evolution & Protocols Notes
  • 8.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section 1 Objectives ¾Describe 3GPP technology evolution. ¾List the key performance requirements for LTE. ¾Distinguish the evolved UTRAN network architecture. ¾Describe the functions of the layers within the E-UTRAN protocol structure. Notes
  • 9.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 3GPP UMTS and WCDMA Releases & Features UMTS and WCDMA Releases and Features Release 99 – Specified the first UMTS 3G networks, incorporating a CDMA air interface. Release 4 – Introduced mainly the CS Core Network split feature plus other minor enhancements. Release 5 – Introduced mainly IMS, HSDPA (allowing broadband services on the Downlink), and other minor enhancements. Release 6 – Integrated operation with Wireless LAN networks and added HSUPA (enables broadband uploads and services), MBMS, and enhancements to IMS such as Push-to-Talk over Cellular (PoC), video conferencing, messaging, etc. Release 7 – Significant progress made in 2006 and 2007 toward completion of this release. Most documents are under revision control. Introduced, among other features, enhancements to High-Speed Packet Access (HSPA+), QoS, and improvements to real-time applications like VoIP. Release 8 – In progress (expected 2009). Introducing, among others, E-UTRA (also called LTE, based on OFDMA), All-IP Network (also called SAE), and Femto cells operation. Release 8 constitutes a re-factoring of UMTS as an entirely IP based fourth-generation network. 3GPP RAN approved the LTE Physical Layer specifications in September 2007. The specifications are 36.201–36.214 and are on the 3GPP site at http://www.3gpp.org/ftp/Specs/html-info/36-series.htm. Each release incorporates hundreds of individual standards documents, each of which may have gone through many revisions. Current 3GPP standards incorporate the latest revision of the GSM standards. Standards documents are available for free on the 3GPP Web site. These standards cover the radio component (Air Interface) and the Core Network, as well as billing information and speech coding down to source code level. Cryptographic aspects (authentication, confidentiality) are also specified in detail. More details about the 3GPP releases content can be found at http://www.3gpp.org/specs/releases-contents.htm and http://www.3gpp.org/Management/WorkPlan.htm.
  • 10.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION LTE and EPS Terminology • Long Term Evolution (LTE): Evolution of 3GPP UMTS Terrestrial Radio Access (E-UTRA) technology • Evolved Packet System (EPS): Evolution of the complete 3GPP UMTS Radio Access, Packet Core and its integration into legacy 3GPP/non-3GPP networks. It includes: – Radio Access Network – Evolved UTRA Network (E-UTRAN) – System architecture – Evolved Packet Core (EPC) • This course uses the terms LTE and E-UTRA interchangeably. Notes
  • 11.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Design Performance Targets • Scalable transmission bandwidth (up to 20 MHz) • Improved Spectrum Efficiency – Downlink (DL) spectrum efficiency should be 2-4 times Release 6 HSDPA. ‹ Downlink target assumes 2x2 MIMO for E-UTRA and single TX antenna with Type 1 receiver HSDPA. – Uplink (UL) spectrum efficiency should be 2-3 times Release 6 HSUPA. ‹ Uplink target assumes 1 TX antenna and 2 RX antennas for both E-UTRA and Release 6 HSUPA. • Coverage – Good performance up to 5 km – Slight degradation from 5 km to 30 km (up to 100 km not precluded) • Mobility – Optimized for low mobile speed (< 15 kph) – Maintained mobility support up—to 350 kph (or even up to 500 km/h) • Advanced TX schemes and multiple-antenna technologies • Inter-working with existing 3G and non-3GPP systems – Interruption time of real-time or non-real-time service handover between E-UTRAN and UTRAN/GERAN shall be less than 300 or 500 ms. User Throughput and Spectrum Efficiency Requirements Detailed throughput requirements: z Downlink: – 5%-tile Downlink user throughput per MHz 2-3 times Release 6 HSDPA – Average Downlink user throughput per MHz 3-4 times Release 6 HSDPA – Downlink spectrum efficiency should be 3-4 times Release 6 HSDPA – Downlink performance targets assume 2 transmit and 2 receive antennas for E-UTRA, and 1 transmit and enhanced Type 1 receiver for Release 6 HSDPA – Downlink user throughput should scale with spectrum allocation z Uplink: – 5%-tile Uplink user throughput per MHz 2-3 times Release 6 HSUPA – Average Uplink user throughput per MHz 2-3 times Release 6 HSUPA – Uplink spectrum efficiency should be 2-3 times Release 6 HSDPA – Uplink performance targets assume 1 transmit and 2 receive antennas for both E-UTRA and Release 6 HSDPA – Uplink user throughput should scale with spectrum allocation and mobile maximum transmit power E-UTRA is expected to outperform Release 6 HSPA by a factor of 2-4 in user throughput and spectrum efficiency. This assumes a maximum cell range up to 5 km. For cell ranges up to 30 km, slight degradations are expected for the achieved performance for the user throughput targets and more significant degradation for the spectrum efficiency targets. However, cell ranges up to 100 km should not be precluded by the specifications.
  • 12.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Main drivers for the evolution: • Faster RRM response for CDS (Channel Dependent Scheduling) • Reduced packet latencies • Interworking with other radio access technologies (GSM, HSPA, HRPD) UMTS Network Architecture Evolution Concepts Centric RRM (RNC-Based) (Dumb Base Stations, Smarter RNCs) Multi-hop user data forwarding 4 NW Nodes (NodeB, RNC, SGSN, GGSN) Dual-hop user data forwarding 2 NW Nodes (NodeB, PGW) Distributed RRM (NodeB-based) (smarter Base Stations, not so smart RNC) Interworking with 3GPP technologies only Interworking with 3GPP and non-3GPP technologies Network Architecture Evolutionary Concepts: Notes
  • 13.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 3GPP Network Architecture Evolution - 4 functional entities on Control and User Planes - RNC-based RRM Control Plane User Plane R99 NodeB RNC GGSN SGSN - Flat Architecture: 2 functional entities on User Plane - E-NodeB-centric RRM Control Plane User Plane E-UTRAN E-NodeB MME SGW/PGW Control Plane User Plane HSPA RNC RNC NodeB GGSN SGSN - Node B performs most of RRM for High Speed DL/UL channels Control Plane User Plane HSPA with Direct Tunneling RNC RNC SGSN GGSN NodeB - User data Packets are directly forwarded to GGSN Main Drivers: z Faster RRM response for CDS z Reduced packet latencies Network Architecture Evolution (decentralization process) z From a centric RNC-Based RRM (stupid Base Stations and smarter RNCs) z To a decentralized Base Station-based RRM (smarter Base Stations, less smart RNCs) z From user packet data forwarding to GGSN through RNC (intermediary RNCs) z To direct user packet data forwarding to GGSN (Direct Tunneling)
  • 14.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section Overview • 3GPP UMTS Evolution Roadmap and Terminology • UTRAN Evolution Toward E-UTRAN • E-UTRAN Network Nodes, Protocol Structure, and Functionalities • EPS Integrated Architecture Notes
  • 15.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Enhanced Node B (eNB) Functions • Radio Resource Management: – Radio Bearer Control – Admission/congestion control – Connection and mobility control – UL/DL dynamic scheduling • IP header compression and encryption of user data • Selection of an MME at UE attachment (if necessary) • Routing of User Plane data towards S-GW • Routing of paging messages from MME towards UE • Measurement and reporting configuration eNB MME / S-GW / P-GW MME / S-GW / P-GW eNB eNB S1 S 1 S 1 S 1 X2 X 2 X 2 E-UTRAN EPC Reference 23.401 z eNB (Evolved Node B) provides the E-UTRA User Plane (PDCP/RLC/MAC/PHY) and Control Plane (RRC) protocol terminations towards the UE. z The eNBs are logically interconnected with each other by means of the X2 interface. z The eNBs are also connected by means of the S1 interface to the EPC (Evolved Packet Core), more specifically to the MME (Mobility Management Entity) by means of the S1-MME and to the Serving Gateway (S-GW) by means of the S1-U. z The S1 interface supports a many-to-many relation between MMEs / Serving Gateways and eNBs.
  • 16.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Serving Gateway (S-GW) & P-GW Functions S-GW • Local Mobility Anchor point for inter-eNB handover • Mobility anchoring for inter-3GPP mobility • E-UTRAN Idle Mode Downlink packet buffering and initiation of network triggered service requests • Lawful interception • Packet routing and forwarding • Transport level packet marking in the UL and DL • UL and DL charging per UE, PDN, and QCI • Termination of U-plane packets • Switching of U-plane for support of UE mobility P-GW •Per-user based packet filtering •Lawful interception •UE IP address allocation •DL rate enforcement based on AMBR For more details, see 3GPP TS 23.401 eNB MME / S-GW / P-GW MME / S-GW / P-GW eNB eNB S1 S 1 S 1 S 1 X2 X 2 X 2 E-UTRAN EPC Notes
  • 17.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MME Functions • NAS signaling and its security • AS Security Control • Inter CN node signaling for mobility between 3GPP access networks • Idle mode UE Reachability (including control and execution of paging retransmission) • Tracking Area List Management (idle and active) • PDN GW and Serving GW selection • MME selection for handovers with MME change • Idle state mobility control • SGSN selection for 3GPP handovers • Roaming and Authentication • EPS bearer management For more details, see 3GPP TS 23.401 eNB MME / S-GW / P-GW MME / S-GW / P-GW eNB eNB S1 S 1 S 1 S 1 X2 X 2 X 2 E-UTRAN EPC Notes
  • 18.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRAN Protocol Stack: User Plane eNB S-GW eNB S 1 - U P X2-UP Uu P-GW S5 IP Networks References: • LTE-Uu: 36.201 (Physical Layer), 36.321 (MAC), 36.322 (RLC), 36.323 (PDCP) • S1: 36.411 (Physical Layer), 36.414 (S1- Data Transport) • X2: 36.421 (Physical Layer); 36.424 (X2 – Data Transport) Transport Layer reference for the S1 and X2 Interfaces: IP in E-UTRAN - Used in user and control planes - IP in E-UTRAN shall also support: 1. NDS/IP (Network Domain Security for IP): Sets up Confidentiality and Integrity for data exchange between network entities 2. Diffserv (Differentiated Services): Enhancements of the IP protocol for QoS References: RFC2475, An Architecture for Differentiated Services GTP (GPRS Tunneling Protocol) in E-UTRAN - GTP goes over UDP/IP transport protocol stack - No flow or error control or any mechanism to guarantee the data delivery of S1-U interface - As a reminder in 3G, GTP is used over the Iu-PS interface (connection between RNC and SGSN)
  • 19.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRAN Protocol Stack: Control Plane References: • LTE-Uu: 36.331 (RRC) • S1: 36.412 (Signaling Transport), 36.413 (Application Protocol) • X2: 36.422 (Signaling Transport), 36.423 (Application Protocol) • IETF RFC 2960 (Stream Control Transmission Protocol) About the SCTP (Stream Control Transmission Protocol): - It is a reliable connection-oriented transport protocol similar to TCP - As TCP, SCTP implements Congestion and flow control, detection of data corruption and loss/duplication of packets - SCTP connection needs to be set up connection between peers before actual data transmission (as TCP) - From functional perspective, there are some key new features in SCTP: 1. Multi-streaming - 2. Multi-homing - 3. Message Level Framing 1. Multi-streaming: - In SCTP protocol, a stream is a unidirectional sequence of user data delivered to upper layers - With Multi-streaming, SCTP allows to set up several independent streams between two peers. With this feature, if transmission error occur in one stream, it does not affect the other streams. - This feature is important for signaling transfers between two nodes of UTRAN where, for instance, the delivery order of each user signaling flow can be preserved, but hey can be delivered independently. - TCP, however, in some instances can also use multiple parallel streams. Example of this is the downloading of web-pages with multiple multimedia objects. 2. Multi-homing - Allows SCTP endpoint to be reached through multiple network addresses - In case of error in one of the address, the retransmitted packets may be sent to an alternate address providing redundancy operation 3. Message level Framing - SCTP works at message level whereas TCP is octet based framing and does not preserve transmitted data structure - In SCTP, messages are transmitted as whole set of bytes if the maximum SCTP length is not reached - This is an advantage for E-UTRAN signaling transport Reference Documents: RFC2960 Stream Control Transmission Protocol
  • 20.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION HA S6a S2a IS-835 IS-835 HS/AAA AAA Ta S101 S2a 1xEVDO Abis PDSN RNC AT AN EPS Architecture S12 Uu UE SGSN Iu CP NodeB RNC S3 Iub Gr HLR/HSS S6a PCRF S7 S1-CP S11 IP Networks UE S1-U LTE-Uu E-NodeB SAE-GW (PDN-GW/S-GW) MME 3GPP TS 23.401 V8.2.0 (2008-06) Technical Specification Group Services and System Aspects; General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access (Release 8). PCRF is the policy and charging control element. PCRF functions are described in more detail in TS 23.203 [6]. z In a non-roaming scenario, there is only a single PCRF in the HPLMN associated with one UE’s IP-CAN session. The PCRF terminates the RX interface and the Gx interface. z In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with one UE’s IP-CAN session: – H-PCRF that resides within the H-PLMN – V-PCRF that resides within the V-PLMN
  • 21.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 2 SECTION E-UTRA Essentials Notes
  • 22.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section 2 Objectives ¾ Describe the E-UTRA air interface capabilities. ¾ Recognize DL and UL time/frequency organization. Notes
  • 23.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Air Interface Capabilities Bandwidth support • Flexible from 1.4 MHz to 20 MHz Waveform • OFDM in Downlink / SC-FDM in Uplink Duplexing mode • FDD: full-duplex (FD) and half-duplex (HD) • TDD Modulation orders for data channels • Downlink: QPSK, 16QAM, 64QAM • Uplink: QPSK, 16QAM, 64QAM MIMO support • Downlink: SU-MIMO and MU-MIMO (SDMA) • Uplink: SDMA Notes
  • 24.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION UE-eNB Communication Link Single (and same) link of communication for DL & UL Effectively: • DL serving cell = UL serving cell • No UL or DL macro-diversity – UL softer HO reception is an implementation choice – UE’s “Active Set” size = 1 • Hard-HO-based mobility – RACH-based mobility procedure to target cell – Network controlled by default – UE initiated under RL failure condition • Load indicator for inter-cell load control – Transmitted over X2 interface Notes
  • 25.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Air Interface Peak Data Rates Downlink • ~300 Mbps in 20 MHz • Assumptions: – 4 stream MIMO – 14.29% Pilot overhead (4 TX antennas) – 10% common channel overhead ‹ Note that this overhead level is adequate to serve 1 UE/subframe. – 6.66% waveform overhead (CP + window) – 10% guard band – 64QAM code rate ~1 Uplink • ~75 Mbps in 20 MHz • Assumptions: – 1 TX antenna – 14.3% Pilot overhead – 0.625% random access overhead – 6.66% waveform overhead (CP + window) – 10% guard band – 64QAM code rate ~1 Notes
  • 26.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Time Domain Organization CP length (config. by higher layer) Number of OFDM Symbols/Slot 4.69µs (Normal CP) 16.66μs (Extended CP) 33.3µs (MBSFN only) 7 OFDM/LFDM symbols 6 OFDM/LFDM symbols 3 OFDM symbols Radio Frame has two Structures: • Type 1 (FS1) for FDD DL/UL • Type 2 (FS2) for TDD This presentation deals only with FS1 Time Domain Organization Basic unit of time Ts, defined with relation to 20 MHz, 15 KHz inter-subcarrier separation and 2048 FFT size (36.211) Ts = 1/(15e3*2048) = 32.55 ns Æ Number of samples in 10 ms is 10 ms/32.55 ns=307200 Tf = 307200Ts = 10 ms Tslot = (307200/20)Ts = 15360Ts z Half radio frame = 5 ms – Contains one sync channel instance – Tailoring efficient HO from GSM z Radio frame = 10 ms – Periodicity of sync channel z PBCH TTI = 40 ms – Periodicity of primary broadcast channel
  • 27.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Frequency Domain Organization RB SC N ( ) UL RB DL RB N N or Channel Bandwidth [MHz] 1.4 3 5 10 15 20 N. of Occupied Subcarriers including DC (NSC) 73 181 301 601 901 1201 FFT Size 128 256 512 1024 1536 2048 Sampling Rate [MHz] 1.92 ½ 3.84 3.84 7.68 2x3.84 15.36 4x3.84 23.04 6x3.84 30.72 8x3.84 N. of Resource Blocks (NRB) 6 15 25 50 75 100 For 15 KHz Carrier Spacing LTE DL/UL air interface waveforms use a number of orthogonal subcarriers to send user traffic data, Reference Signals (Pilots), and Control Information. Channel Bandwidth and Transmission Bandwidth More information can be found in TS36.101. z OFDM uses all the subcarriers for a single user, whereas OFDMA uses different subcarriers for different users. z There are different types of subcarriers: Data, Pilot, Control, Null, etc. z There are two guard bands at the edges of the OFDM/OFDMA-signal (no RF transmission in these subcarriers). Each guard band exists to avoid interference with adjacent bands. z Taking into account the guard band subcarriers and the DC subcarrier, the number of available subcarriers is as shown in the table.
  • 28.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION UL/DL Resource Grid Definitions Resource Element (RE) • One element in the time/frequency resource grid – One subcarrier in one OFDM/LFDM symbol for DL/UL Resource Block (RB) • Minimum scheduling size for DL/UL data channels • Physical Resource Block (PRB) – 180 kHz x 0.5 ms ‹ 12 subcarriers x 1 slot for 15 kHz subcarrier spacing ‹ 24 subcarriers x 1 slot for 7.5 kHz subcarrier spacing time frequency Notes
  • 29.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 3 SECTION Downlink Channels & Procedures Notes
  • 30.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section 3 Objectives ¾Describe DL channel structure and mapping. ¾Provide DL time/frequency OFDMA numerology. ¾Provide DL physical channels resource allocation. ¾Describe overall DL operation. Notes
  • 31.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Channelization Hierarchy Most DL data traffic is carried on the Down Link Shared Channel (DL-SCH) transport channel and its corresponding Physical Downlink Shared Channel or PDSCH Dedicated Data/Control Paging System broadcast MBSFN Common Control Downlink Physical Signals LOGICAL CHANNELS (What type of information transfer services are offered by the MAC layer) Different kinds of data transfer services as offered by MAC. Each logical channel type is defined by what type of information is transferred z Control Channels (for the transfer of control plane information) z Traffic Channels (for the transfer of user plane information) CONTROL LOGICAL CHANNELS (C-Plane information) – Broadcast Control Channel (BCCH) - System information – Paging Control Channel (PCCH) - Paging information – Multicast Control Channel (MCCH) - Point-to-multipoint channel for MBMS control information – Dedicated Control Channel (DCCH) - Unicast control channel – Common Control Channel (CCCH) - Point-to-multipoint channel used before RRC connection established TRAFFIC LOGICAL CHANNELS (U-Plane information) – Dedicated Traffic Channel (DTCH) - Unicast traffic channel – Multicast Traffic Channel (MTCH) - Point-to-multipoint channel for MBMS traffic TRASPORT CHANNELS (How different type of information is going to transferred over the Air Interface) The physical layer offers information transfer services to MAC and higher layers. The physical layer transport services are described by how and with what characteristics data are transferred over the radio interface: Broadcast Channel (BCH) characterised by: - fixed, pre-defined transport format; requirement to be broadcast in the entire coverage area of the cell. Downlink Shared Channel (DL-SCH) characterised by: - support for HARQ; - support for dynamic link adaptation - possibility to use beamforming; - support for both dynamic and semi-static resource allocation; - support for UE discontinuous reception (DRX) to enable UE power saving; - Support for MBMS transmission. NOTE: The possibility to use slow power control depends on the physical layer. Paging Channel (PCH) characterised by: - support for UE discontinuous reception (DRX) to enable UE power saving (DRX cycle is indicated by the network to the UE); - Requirement to be broadcast in the entire coverage area of the cell; - mapped to physical resources which can be used dynamically also for traffic/other control channels. Multicast Channel (MCH) characterised by: - requirement to be broadcast in the entire coverage area of the cell; - support for MBSFN combining of MBMS transmission on multiple cells; - support for semi-static resource allocation e.g. with a time frame of a long cyclic prefix. Physical Channels Control Related Information: CFI – Control Format Indicator is transmitted in PCFICH HI - HARQ Indicator is transmitted in PHICH DCI – Down Link Control Indicator is transmitted in PDCCH UCI – Uplink Control Information sent on PUCCH/PUSCH
  • 32.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Physical Channels LTE vs. HSPA LTE PDCCH Physical Downlink Control Channel DL Support: - Allocated DL resources - Modulation Scheme - HARQ info - Transport Format - C-RNTI - Paging Indicators UL Support: - UL Grants with specific allocation of resources PCFICH Physical Control Format Indicator Channel PHICH Physical HARQ ACK/NAK Indicator Channel PDSCH Physical Downlink Shared Channel HSPA E-HICH E-RGCH HS-SCCH E-AGCH HS-PDSCH Downlink Control Channels Operation Support Support for DL Operation z PDCCH transmits information about Resource allocation, HARQ info, Transport format, and implicitly the RNTI for the DL transmission. Similar to HS-SSCH functionalities in HSDPA. z In support of MIMO, there is also some additional information transmitted: 1) The codebook entry, and 2) The transmission rank of the following DL packet. Support for UL Operation z PDCCH can also transmit scheduling grants to the UE. In LTE there is a need to explicitly signal the UL granted resources differently than HSPA (CDMA-based) where only Allowed Power levels are granted. Multiple UEs cannot simultaneously access same subcarriers in an uncontrolled manner. The scheduling grants in HSUPA are managed through E-AGCH and the E-RGCH. z PDCCH has many functionalities and not all of them are used at the same time. Hence, PDCCH requires flexibility with regard to possible configurations. This results in a variable size of the PDCCH and requires an additional channel to inform the UE of a specific configuration. The PCFICH signals how many OFDM symbols (0-3) are occupied by the PDCCH. Support for UL HARQ PHICH sends acknowledgments on DL for UL UE transmitted data. Similar functionality as E-HICH in HSPA. Additional Physical Channels z Physical Broadcast Channel (PBCH) – Carrying part of BCH z Physical Multicast Channel (PMCH) – Carrying MCH (MBSFN multicast) Signals z Reference Signal (RS) (a.k.a Pilots) z Synchronization signals – Primary Synchronization Signal (PSC) – Secondary Synchronization Signal (SSC)
  • 33.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Synchronization Signals (SCH) Used for Initial System Acquisition • Time/frequency synchronization – Carrier frequency determination – OFDM symbol/subframe/frame timing • Cell ID determination (504 Possible cell IDs) – Cell-IDs are grouped into 168 unique physical- layer cell-identity groups, each group contains 3 unique IDs (168*3 = 504) Transmitted in • Time: subframe 0 and 5 in every radio-frame • Frequency: middle 1.08MHz (6 RBs) Primary synchronization signal (TX on P-SCH) • Provides the cell ID within the cell ID group (1 of 3) • Transmitted in last OFDM symbol of subframes 0 and 5 (provides sub-frame timing) Secondary synchronization signal (TX on S-SCH) • Provides the 168 cell ID group information • M-sequences with scrambling (different “generation” method for SF0 and SF5, provides frame timing) PDSCH PDCCH 6-100 RBs 6 RBs 6x180KHz=1.08MHz PDSCH PDSCH PCFICH PHICH PDCCH S-SCH P-SCH Cell ID Determination using P-SCH and S-SCH Signals There are 504 unique physical-layer cell identities. The physical-layer cell identities are grouped into 168 unique physical-layer cell- identity groups, each group containing 3 unique identities (168*3 = 504) . The grouping is such that each physical-layer cell identity is part of one and only one physical-layer cell-identity group. A physical-layer cell identity is thus uniquely defined by a number in the range of 0 to 167, representing the physical-layer cell-identity group, and a number in the range of 0 to 2, representing the physical-layer identity within the physical-layer cell-identity group. Acquisition Procedure z The initial cell search begins after the UE is switched on. At this time the UE does not know anything about the cells around it and it begins to look for strong cells in the DL band. z Once the UE has found a good candidate with strong 72 subcarriers (6x12) that might carry the synchronization sequences and the BCH, the UE performs a rough frequency synchronization. z The UE looks for the Primary Synchronization Channel (P-SCH). Once it has found it, it knows the exact carrier frequency and the timing of the slot 0 or 10. By trial and error, the UE also knows the CP configuration. z During the previous process, the UE also performed the first step to find the Physical Layer cell ID. Each of the 3 P-SCH sequences is linked to one group member of the 168 different cell ID groups. z The next step is to detect the S-SCH. The SCH is transmitted 1 OFDM symbol before the P-SCH. Once S-SCH is detected, the radio frame and the Physical Layer cell ID are perfectly known. z The UE is ready to read BCH at this time and can also read the PLMN ID from the system information on the BCCH. z UE registers in the cell. Additional information about Synchronization Sequences Primary Synchronization Signal uses: - Frequency domain Zadoff-Chu sequence of length 62 Secondary Synchronization Signal uses: - Interleaved concatenation of two length-31 binary sequences. The concatenated sequence is scrambled with a scrambling sequence given by the primary synchronization signal. - The combination of the two length-31 sequences defining the secondary synchronization signal differs between subframe 0 and subframe 5. according tothe method of interleaving (This difference helps the UE to identify the start of a new frame)
  • 34.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Broadcast Channel (PBCH) Carries the Broadcast Transport Channel • Overall DL transmission bandwidth • Number of transmit antennas • DL-RS Transmit Power • System Frame Number, etc Transmitted in • Time: subframe 0 in every radio-frame – 4 OFDM symbols in the subframe • Frequency: middle 1.08MHz (6 RBs) TTI = 40 ms • Transmitted in 4 bursts at a very low data rate Transmission such that • Every burst is self-decodable • CRC check uniquely determines the 40ms PBCH TTI boundary PDSCH PDCCH 6-100 RBs 6 RBs 6x180KHz=1.08MHz PDSCH PDSCH PCFICH PHICH PDCCH S-SCH P-SCH PBCH
  • 35.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Control Format Indicator (PCFICH) Used for Signaling the PDCCH control region: • 1, 2 or 3 OFDM symbols for overall TX BW > 10 RBs • Control region quantized to full OFDM symbols – Control and data do not occur in same OFDM symbol Transmitted in: • Time: 1st OFDM symbol of all subframes • Frequency: spanning the entire system band – 4 REGs Æ 16 REs – Mapping depending on Cell ID Reference Signal Embedded OFDM Symbols 1 ms 5 ms 10 ms subframe 0 1 2 3 4 5 6 7 8 9 Notes
  • 36.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Downlink Control Channel (PDCCH) Used for: • DL/UL Resource Assignments • Multi-user Transmit Power Control (TPC) commands • Paging indicators Different PDCCH formats are defined: • 1-3 OFDM symbols in a sub-frame • PCFICH using the first OFDM symbol of each subframe informs PDCCH specific format PDCCHs are constructed as follows • CCE is defined as a unit of 36 REs • A PDCCH instance is constructed as 1, 2, 4 or 8 CCEs Reference Signal Embedded OFDM Symbols 1 ms 5 ms 10 ms subframe 0 1 2 3 4 5 6 7 8 9 PDCCH Carries DCI – Downlink Control Information z Uplink assignments: – RB assignment, transport block size, retransmission sequence number, power control command, cyclic shift of DM RS for SDMA, etc. z Downlink assignments: – RB assignment, transport block size, HARQ process number, Redundancy Version index, Uplink power control command z Uplink Power Control Commands z Paging Indicator L1/L2 control channel for: z DL scheduling, including: – Regular unicast data – Scheduling of Paging messages ‹ Acting as a “paging indicator” – Scheduling of SIBs – Scheduling of random access responses z UL grants, including: – Regular unicast data – Requests for aperiodic CQI reports z Multi-user TPC commands: – TPC commands for PUCCH or PUSCH for multiple UEs
  • 37.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Downlink Shared Channel (PDSCH) Used to transmit DL packet data • One Transport Block transmission per UE’s code word per subframe • A common MCS per code word per UE across all allocated RBs – Independent MCS for two code words per UE • 7 PDSCH TX modes Mapping to Resource Blocks (RBs) • Mapping for a particular transmit antenna port shall be in increasing order of: – First the frequency index and then the time index, starting with the first slot in a subframe. Reference Signal Embedded OFDM Symbols 1 ms 5 ms 10 ms subframe 0 1 2 3 4 5 6 7 8 9 Notes
  • 38.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical HARQ Indicator PHICH Used for ACK/NAK of UL-SCH transmissions Transmitted in • Time – Normal duration: 1st OFDM symbol – Extended duration: Over 2 or 3 OFDM symbols • Frequency – Spanning all system bandwidth – Mapping depending on Cell ID FDM multiplexed with other DL control channels Support of CDM multiplexing of multiple PHICHs • PHICHs mapped to same resources constitute a PHICH group. • Coding: ACK bit repeated 3 times before “spreading” • Spreading of coded bits using Hadamard codes – SF = 4 for normal CP (results in 12 RE) – SF = 2 for extended CP (results in 6 RE) Reference Signal Embedded OFDM Symbols 1 ms 5 ms 10 ms subframe 0 1 2 3 4 5 6 7 8 9 Notes
  • 39.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL Reference Signals: 1 TX Antenna DL RS transmitted on 2 OFDM symbols every slot • 6 subcarrier spacing subcarrier subcarrier RB Cell-specific DL Reference Signal (Common Pilots, FS1 and FS2) z Time and Frequency resource allocations: – Allocated on a per Antenna port basis: {0, 1, 2, 3, 4} physical antenna ports – Antenna 0 and 1 transmitted on 2 OFDM symbols every slot ‹ 6 subcarrier spacing and 2x staggering (45 kHz freq sampling) – Antenna 2 and 3 transmitted on 1 OFDM symbol in every slot ‹ 6 subcarrier spacing with 2x staggering across slots – Same frequency spacing for normal and extended CP numerologies
  • 40.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL Reference Signals: 2 TX Antenna subcarrier subcarrier RB Notes
  • 41.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL Reference Signals: 4 TX Antenna Overheads Normal CP Ext CP 1 Tx antenna 4.76% 5.56% 2 Tx antenna 9.52% 11.11% 4 Tx antenna 14.29% 15.87% subcarrier subcarrier RB Notes
  • 42.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Transmission – An Example Example of Frame Structure Type 1 (extended CP) transmission 0 PCFICH PHICH PDCCH RS PDSCH Physical Resource Block (PRB) 2 1 3 Frequency Time Slot Sub Frame Downlink Transmission – An Example The slide shows how a subframe FS1 (extended CP) ends up being transmitted. Observe the first OFDM symbol cell-specific reference signal, PCFICH, informing the assigned UEs of the corresponding PDCCH format. Also PDCCH is transmitted in the first 1-3 OFDM symbols carrying resource allocation and MCS to the corresponding allocated UEs.
  • 43.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section Overview • E-UTRA DL Channelization Hierarchy and Mapping • Downlink Physical Channel Resource Allocations • DL Operation Procedures (Link Adaptation) • DL Transmission Chain Notes
  • 44.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL Operation Highlights: Similarities to HSPA • Shared Channel Operation • CDS (Channel Dependent Scheduling) –Requires Channel Quality Information (CQI) sent on the UL –Requires Pre-coding and Rank information sent on the UL for MIMO • AMC (Adaptive Modulation and Coding) –Requires informing the UE about allocated Resources –Requires informing the UE about Modulation and Coding Schemes (MCS) • HARQ (Hybrid ARQ) –Uses Asynchronous adaptive retransmissions –Uses Synchronous ACK/NAKs –Requires ACK/NAK sent on the UL • DL Modulation: QPSK, 16-QAM, 64-QAM Notes
  • 45.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION • Multiple Access Dimensions: • DL Scheduler: –Assigns Time/Frequency resources, rather than Time/Code resources –May coordinate with neighbor Base Stations for interference management. • DL Reference Signals (Pilots): –Have fixed time duration and frequency sub-band allocations. • ARQ runs at E-NodeB –ARQ architecture is conceptually similar to HSPA. (It supports TM, UM, and AM modes and retransmissions are based on status reports.) –Optional HARQ assisted ARQ operation is possible in LTE. • Multiple PDSCH Tx Modes - Requires different Channel Quality Reporting, acknowledging and scheduling mechanisms DL Operation Highlights: Differences from HSPA LTE HSPA (R7) Time (TDMA) Frequency (OFDMA) Space (SU-MIMO, SDMA/MU-MIMO) Time (TDMA) Code (CFDMA) Space (SU-MIMO) Notes
  • 46.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Data Transfer (1 of 3): Functionality Split across Layers PDCP (ROHC, Security) HSPA (DL) Logical Channels MAC-d Flows Transport Channels Packets from GGSN RLC (ARQ) MAC-d HARQ Multiplexing Scheduling & Priority Handling Physical Layer RNC Node B MAC-hs Radio Bearers Iu Iterface HS-DSCH HS-PDSCH Downlink Data Transfer: Functionality Split Across Layers HARQ Principles (within MAC Layer): z N-process Stop-And-Wait, Asynchronous adaptive HARQ z Uplink ACK/NAKs are sent on PUCCH or PUSCH. z PDCCH signals the HARQ process number and if it is a transmission or retransmission. z Retransmissions are always scheduled through PDCCH. ARQ Principles (within RLC Layer): z ARQ retransmits RLC PDUs or RLC PDU segments. z ARQ retransmissions are based on RLC status reports and optionally ARQ/HARQ interactions. z Polling for RLC status report is used when needed by RLC. ARQ/HARQ Interaction: z Optional HARQ assisted ARQ operation z ARQ uses knowledge from the HARQ about transmission failure status and RLC retransmission and re-segmentation can be initiated.
  • 47.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Downlink Data Transfer (2 of 3) Functionality split across physical layer • Max Code Words: 2 – 1 Code Word for rank 1 Transmission – 2 Code Words for rank 2/3/4 Transmissions • Layer Mapping: Fixed mapping between code words to layers • Max Tx Antennas: 4 – Potentially up to 4 layers • Pre-coding: – Code book based precoding • Channel Dependant precoding and Rank Indicator reported by the UE for closed loop MIMO Mapper OFDM signal generation Layer Mapper Scrambling Precoding Modulation Mapper Modulation Mapper OFDM Mapper OFDM signal generation Scrambling code words antenna ports OFDM layers •DL Multiple Antenna Transmission: Generalized PDSCH TX A brief description of the generalized transmission blocks z scrambling of coded bits in each of the code words to be transmitted on a physical channel z modulation of scrambled bits to generate complex-valued modulation symbols z mapping of the complex-valued modulation symbols onto one or several transmission layers z precoding of the complex-valued modulation symbols on each layer for transmission on the antenna ports z mapping of complex-valued modulation symbols for each antenna port to resource elements z generation of complex-valued time-domain OFDM signal for each antenna port Multiple Antenna Transmission/Reception (MIMO) schemes were inherent in the design of E-UTRA (R8) MIMO classifications from the Number of Code Words Perspective: Single Code Word (SCW) -> Use one Channel Coder per user Multiple Code Word (MCW) -> Use Multiple Channel Coders per user MCW offers better performance relative to SCW at the expense of additional complexity and signaling LTE employs MCW (up to two Code Words) for MIMO transmissions. Advantages and disadvantages of using either SCW or MCW The SCW scheme has simple HARQ identical to SISO, simple ACK/NACK messaging identical to SISO, and low complexity MMSE receiver. The drawback of SCW is that it is not capacity achieving and suffers from a throughput loss in low rank channels, such as, spatially correlated channels or LOS channels with high Rician K-factor. MCW allows Per Antenna Rate Control (PARC) and Successive Interference Cancellation (SIC). the MCW transmission with a successive interference cancellation (SIC) receiver is capacity achieving and hence optimal in performance. A successive interference cancellation (SIC) receiver is used to decouple the M layers providing higher throughput and more tolerance to spatial correlation. However, MCW with SIC comes at the cost of increased signaling overhead, receiver complexity and memory requirements. The signaling overhead for the Reverse Link and Forward Link Control channels are larger than a SCW transmission since the channel quality CQI, coding and modulation, and acknowledgements have to be signaled for each MIMO layer. Furthermore, the SIC receiver memory requirements are high since the MIMO channel and received signals have to be stored for all HARQ transmissions. The receiver processing is more complicated and bursty since lower layers can not be decoded until the upper layers are decoded. M.M. Mao, et.al, “Multi-Antenna Techniques in Ultra Mobile Broadband Communication Systems,” IEEE Communications Networks and Services Conference, 2008
  • 48.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Mode 1: Single-antenna port; port 0 • Transmissions using a single Tx antenna at eNodeB (“conventional” approach) Mode 2: Transmit diversity • transmissions using Alamouti alike transmit diversity schemes Mode 3: Open-loop spatial multiplexing • transmissions using spatial multiplexing (up to two codewords), but no PMI feedback • Also exploits Cyclic Delay Diversity (CDD) transmissions Mode 4: Closed-loop spatial multiplexing • transmissions in closed loop SU-MIMO configuration (PMI and RI feedback) • Up to two codewords, 4 layers, 4 antennas Mode 5: Multi-user MIMO • Closed loop MU-MIMO or Space Division Multiple Access (SDMA) configuration • Different users can use same time/frequency resources in different location within a cell Mode 6: Closed-loop Rank=1 precoding • Same as Mode 4 without the need of Rank reports Mode 7: Single-antenna port; port 5 • Same as Mode 1 using UE-specific Reference Signals PDSCH TX mode is signaled using different DCI Types over PDCCH Downlink Data Transfer (3 of 3) PDSCH Multiple Transmission Modes A UE not configured to receive PDSCH data transmissions based on one of the transmission modes may receive PDSCH data transmissions with DCI format 1A signalled by a PDCCH in its UE specific search spaces or the common search spaces. -Multi-antenna transmission with 2 and 4 transmit antennas is supported. -The maximum number of codeword is two irrespective to the number of antennas with fixed mapping between code words to layers. -Spatial division multiplexing (SDM) of multiple modulation symbol streams to a single UE using the same time-frequency resource, also referred to as Single-User MIMO (SU-MIMO) is supported. When a MIMO channel is solely assigned to a single UE, it is known as SU-MIMO. -Spatial division multiplexing of modulation symbol streams to different UEs using the same time- frequency resource, also referred to as MU-MIMO, is also supported. There is semi-static switching between SU-MIMO and MU-MIMO per UE.
  • 49.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-NodeB E-NodeB MME X1 PDSCH multiple TX modes PDSCH Physical Downlink Shared Channel PDCCH Physical Downlink Control Channel PFICH Physical Format Indicator Channel PUCCH Physical Uplink Control Channel DL Scheduled Operation Overview PFICH PDCCH PUCCH or PUSCH IP Network X2 1. UE reports CQI (Channel Quality Indicator), PMI (Pre-coding Matrix Index) and RI (Rank Indicator) in PUCCH (or PUSCH if there is UL traffic) 2. Scheduler at E-NodeB dynamically allocates resources to UE: - UE reads PCFICH every subframe and finds out the number of OFDM symbols occupied by PDCCH - UE finds about TX Mode and assigned resources (PRB and MCS) reading PDCCH 3. E-NodeB sends user data in PDSCH 4. UE attempts to decode the received packet and sends ACK/NACK using PUCCH (or PUSCH if there is UL traffic) Basic Scheduler Operation: - MAC in eNB includes a dynamic resource scheduler that allocate physical layer resources for the DL-SCH and UL-SCH transport channels - Different schedulers operate on DL-SCH and UL-SCH - The scheduler takes into account the traffic volume and the QoS requirements of each UE and associated radio bearers when sharing resources between UEs - DL Scheduler also assign resources taking into account the radio conditions as identified by the UE through reported measurements - Radio resource allocations can be valid for one or multiple TTIs - Resource assignment consists of physical resource blocks (PRB) and MCS - Allocations for time periods longer than one TTI might also require additional information (allocation time, allocation repetition factor…). - In the downlink, E-UTRAN can dynamically allocate resources (PRBs and MCS) to UEs at each TTI via the C-RNTI on L1/L2 control channel(s) - A UE always monitors L1/L2 control channel(s) in order to find possible allocation when its downlink reception is enabled (activity governed by DRX) - In addition, E-UTRAN can allocate persistent downlink resources for the first HARQ transmissions to UEs. When required, retransmissions are explicitly signalled via the L1/L2 control channel(s). - In the sub-frames where the UE has persistent resource, if the UE cannot find its C-RNTI on the L1/L2 control channel(s), a downlink transmission according to the persistent allocation that the UE has been assigned in the TTI is assumed. - Otherwise, in the sub-frames where the UE has persistent resource, if the UE finds its C-RNTI on the L1/L2 control channel(s), the L1/L2 control channel allocation overrides the persistent allocation for that TTI and the UE does not decode the persistent resources.
  • 50.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION CQI/PMI/RI Reporting Overview E-NodeB PUSCH PUCCH Reporting on PUSCH - Aperiodic Reports -Wideband CQI (multiple-PMI per subband) -UE Selected Subband CQI (No-PMI, Multiple-PMI) -Higher Layer Configured Subband CQI (No-PMI, Single-PMI) -Frequency selective/non-selective scheduling Reporting on PUCCH -Periodic Reports -Wideband CQI (No-PMI, Single-PMI) -UE Selected Subband CQI (No-PMI, Single-PMI) -Frequency selective/non-selective scheduling Aperiodic CQI/PMI/RI reporting is defined by the following characteristics: - The report is scheduled by the eNB via the PDCCH - Transmitted together with uplink data on PUSCH - From the frequency span perspective these reports can be: - Frequency selective: UE Selected Subband CQI and Higher Layer Configured Subband CQI - Frequency non-selective: Wideband CQI reports - When a CQI report is transmitted together with uplink data on PUSCH, it is multiplexed with the transport block by L1 (i.e. the CQI report is not part of the uplink the transport block). Periodic CQI/PMI/RI reporting is defined by the following characteristics: - Periodic CQI reports are sent on PUCCH - From the Frequency span perspective these reports can be: - Frequency selective: UE Selected Subband CQI - Frequency non-selective: Wideband CQI reports A UE can be configured to have both periodic and aperiodic reporting at the same time - In case both periodic and aperiodic reporting occurs in the same subframe, only the aperiodic report is transmitted in that subframe. Observe that both types of reports: Periodic over PUCCH and Aperiodic over PUSCH enable efficient Frequency-Diverse Scheduling (FDS) and Frequency-Selective Scheduling (FSS). Frequency-diverse (non-selective) scheduling (FDS)
  • 51.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Dynamic Scheduling: E-UTRAN dynamically allocates resources (PRBs and MCS) to UEs at each TTI via the C-RNTI on PDCCH(s) • UE monitors the PDCCH(s) in order to find possible allocation when its downlink reception is enabled (activity governed by DRX when configured) Semi-persistent Scheduling: Initially PDCCH indicates if the DL grant can be implicitly reused in the following TTIs according to the periodicity defined by RRC • RRC defines the periodicity of the semi-persistent DL grant – Characterized by a start frame number, periodicity and packet format (one or more may be defined) • Retransmissions are explicitly signalled via the PDCCH(s). E-UTRA DL Scheduling Principles For persistent assignments z In the sub-frames where the UE has semi-persistent downlink resource, if the UE cannot find its C-RNTI on the PDCCH(s), a downlink transmission according to the semi-persistent allocation that the UE has been assigned in the TTI is assumed. z in the sub-frames where the UE has semi-persistent downlink resource, if the UE finds its C- RNTI on the PDCCH(s), the PDCCH allocation overrides the semi-persistent allocation for that TTI and the UE does not decode the semi-persistent resources.
  • 52.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION DL ARQ/HARQ Principles and Interaction HARQ Principles (within MAC Layer) • N-process Stop-And-Wait, Asynchronous adaptive HARQ • Uplink ACK/NAKs are sent on PUCCH or PUSCH. • PDCCH signals the HARQ process number and whether it is a transmission or retransmission. • Retransmissions are always scheduled through PDCCH. ARQ Principles (within RLC Layer) • ARQ retransmits RLC PDUs or RLC PDU segments. • ARQ retransmissions are based on RLC status reports and optionally ARQ/HARQ interactions. • Polling for RLC status report is used when needed by RLC. ARQ/HARQ Interaction • Optional HARQ assisted ARQ operation • ARQ uses knowledge from the HARQ about transmission failure status and RLC retransmission and re-segmentation can be initiated. Notes
  • 53.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION CQI/PMI/RI and ACK/NACKs multiplexing on PUCCH is possible: • Format 2: – CQI/PMI/RI not multiplexed with ACK/NAK • Format 2a/2b – CQI/PMI/RI multiplexed with ACK/NAK (normal CP) • Format 2: – CQI/PMI or RI multiplexed with ACK/NAK (extended CP) ACK/NACK for PDSCH Transmissions The UE shall, upon detection of a PDSCH transmission in subframe n-4 intended for the UE and for which an ACK/NACK shall be provided, transmit the ACK/NACK response in subframe n. ACK/NACKs alone can be delivered PUCCH format 1a and 1b
  • 54.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 4 SECTION Uplink Channels & Procedures Notes
  • 55.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section 4 Objectives ¾ Describe channel structure and mapping for UL. ¾ Provide time/frequency SC-FDMA numerology for UL. ¾ Describe physical channel resource allocation for UL. ¾ Describe overall UL operations. Notes
  • 56.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA UL Channels and Signals Signals • Demodulation Reference Signal (DM-RS) • Sounding Reference Signal (SRS) Control • ACK, CQI, Rank Indicator (RI), Precoding support (PMI) • Scheduling Request (SR) • Single “control” channel - Physical Uplink Control Channel (PUCCH) Data • Unicast data and data + control • Single “data” channel - Physical Uplink Shared Channel (PUSCH) Random access • Preamble sequences in Physical Random Access Channel (PRACH)
  • 57.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA UL Waveform: SC-FDM • OFDM based UL transmission would lead to higher Peak-to- Average Power Ratio (PAPR) than the SC-FDM (TR25.814 Section 9.2.1.4). • Single Carrier Waveform (SC-FDM or DFT-spread OFDM) – Requires Data and control channels to be multiplexed prior to the DFT operation at the transmitter • “Price” of maintaining Single Carrier Waveform – 32 channel combinations == Multiplexing “rules” » Data, ACK, CQI, SRS, SR » No channel can be transmitted independently of the other • Data and UL Demodulation Pilots (Reference Signals) are TDM In OFDM each sub-carrier carries information from a specific modulation symbol and given the nature of this OFDM signal the PAPR due to the simultaneous transmission of multiple carriers can be significant. In SC-FDM each sub-carrier carries information from all transmitted modulation symbols since the latter are spread by the DFT operation and then mapped to each sub-carrier. This single carrier transmission achieved by an IDFT operation followed by an FFT operation results in a lower PAPR. Careful multiplexing of data and control information is required for SC-FDM transmission.
  • 58.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Uplink Channelization Hierarchy No dedicated transport channels: Focus on “shared” transport channels Dedicated Control/Traffic Common Control UCI Physical Control E-UTRA Uplink Channel Structure TS36.321 Section 4.5 MAC specifications include the details about the mapping of logical channels onto transport channels, and TS36.212 Section 4 about the mapping of transport channels on physical channels. Logical Channels: z Common Control Channel (CCCH) – For Idle Mode (RRC_IDLE) connection establishment (e.g., call setup, registration) z Dedicated Control Channel (DCCH) – For Connected Mode (RRC_CONNECTED) signaling z Dedicated Traffic Channel (DTCH) – For Connected Mode (RRC_CONNECTED) user data traffic Transport Channels: z Random Access Channel (RACH) – Uplink random access z Uplink Shared Channel (UL-SCH) – Signaling and traffic are multiplexed onto UL-SCH Physical Channels: z Physical Random Access Channel (PRACH) z Physical Uplink Control Channel (PUCCH) – For carrying physical control information – Uplink control information (UCI) if PUSCH is not configured z Physical Uplink Shared Channel (PUSCH) – For carrying dedicated control/traffic as well as UCI
  • 59.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION LTE PUCCH or PUSCH Physical Uplink Control Channel (used to carry Control Information) DL Support: - Channel Quality Information (CQI and/or PMI) - HARQ ACK/NAK - Rank Indication UL Support: - Scheduling request - Buffer Status Report - Power Headroom Report - Transport Format - Uplink HARQ information - C-RNTI MAC Control Element PRACH Physical Random Access Channel PUSCH Physical Uplink Shared Channel (used to carry user data) HSPA E-DPDCH HS-DPCCH PRACH E-DPDCH E-DPCCH Uplink Physical Channels LTE vs. HSPA Uplink Physical Channels LTE vs. HSPA Uplink Control Information (UCI) contains: z Channel Quality Information (Channel Quality Indicator - CQI and/or Precoding Matrix Indicator - PMI) – For HSPA, this is sent on HS-DPCCH. z HARQ-ACK (Acknowledgements) – For HSPA, this is sent on HS-DPCCH. z Rank Indication – For HSPA+, rank information is sent in extended CQI range on HS-DPCCH. z Scheduling Request, Buffer Status Report and Power Headroom Report – For HSPA, scheduling information (SI) is sent in-band on E-DPDCH. z Transport Format and Uplink HARQ Information – For HSPA, the transport format and Uplink HARQ information is sent on E-DPCCH. z C-RNTI MAC Control Element – There is no equivalent information needed in HSPA due to the use of dedicated transport and physical channels. UCI may be mapped onto PUSCH or PUCCH. z PUSCH can carry user data and Uplink Control Information (UCI). z PUCCH carries only the Uplink Control Information (UCI), and is used only when UE is not transmitting PUSCH.
  • 60.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Uplink Reference Signals •Two types of E-UTRA/LTE Uplink Reference Signals: • Demodulation reference signal – Associated with transmission of PUSCH or PUCCH – Purpose: Channel estimation for uplink coherent demodulation/detection of the uplink control and data channels – Transmitted in time/frequency depending on the channel type (PUSCH/PUCCH), format, and cyclic prefix type • Sounding reference signal – Not associated with transmission of PUSCH or PUCCH – Purpose: Uplink channel quality estimation feedback to the uplink scheduler (for Channel Dependent Scheduling) at the e-NodeB – Transmitted in time/frequency depending on the SRS bandwidth and the SRS bandwidth configuration (some rules apply if overlap with PUSCH and PUCCH) Notes •The same set of base sequences is used to generate demodulation and sounding reference signals •The base sequences and the reference signals are derived from Zadoff-Chu sequences •Cyclic shifts can be applied to a base sequence to obtain multiple reference signal sequences
  • 61.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Uplink Shared Channel (PUSCH) PUSCH Normal Cyclic Prefix Extended Cyclic Prefix Demodulation-RS Embedded SC- FDMA Symbols 1 Subframe = 1 ms PUSCH PUSCH 5 ms 1 Radio Frame = 10 ms Subframe 0 1 2 3 4 5 6 7 8 9 1 Time Slot Frequency Hopping No Frequency Hopping Frequency diversity through hopping Demodulation Reference Signal (DM-RS) l = 0 l = 7 l = 0 l = 6 PUSCH More information can be found in TS36.211. z Details about Demodulation Reference Signal on PUSCH can be found in §5.5.2.1.2. z Details about Demodulation Reference Signal on PUCCH can be found in §5.5.2.2.2. The reference signal sequence shall be multiplied with the amplitude scaling factor and mapped resource elements. The resource element mapping shall be in increasing order of first k (sub- carrier), then l (symbol), and finally the slot number.
  • 62.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION PUSCH Frequency Hopping Demodulation-RS Embedded SC- FDMA Symbols 6-100 RBs 1 Subframe = 1 ms PUSCH PUSCH 5 ms 1 Radio Frame = 10 ms Subframe 0 1 2 3 4 5 6 7 8 9 PUSCH Intra- and Inter- Subframe Hopping 6-100 RBs Inter- Subframe Hopping PUSCH Frequency Hopping More information about PUSCH frequency hopping can be found in TS36.211 §5.3.4.
  • 63.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION PUSCH Transmission UL data transmission • One Transport Block transmission per codeword per subframe Mapping to resource elements • Mapping shall be in increasing order of first the frequency index, then the time index, and finally the slot number (i.e., starting with the first slot in the subframe).
  • 64.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Physical Uplink Control Channel (PUCCH) Demodulation-RS Embedded SC- FDMA Symbols 6-100 RBs 1 Subframe = 1 ms PUCCH PUSCH 5 ms 1 Radio Frame = 10 ms Subframe 0 1 2 3 4 5 6 7 8 9 PUCCH PUCCH PUCCH PUCCH PUCCH PUCCH PUCCH Frequency Hop at Time Slot Boundary Format 2, 2a, 2b 1 Time Slot Demodulation Reference Signal (DM-RS) PUCCH l = 0 Normal Cyclic Prefix Extended Cyclic Prefix PUCCH Normal Cyclic Prefix Extended Cyclic Prefix 1 Time Slot Format 1, 1a, 1b PUCCH uses one resource block in each of the two slots in a subframe. l = 7 l = 0 l = 7 l = 0 l = 6 l = 0 l = 6 Physical Uplink Control Channel (PUCCH) The physical Uplink control channel, PUCCH, carries Uplink control information (UCI), and is never transmitted simultaneously with the PUSCH from the same UE. A maximum of 4 resource blocks are reserved for PUCCH in this example. The physical resources used for PUCCH depend on parameters given by higher layers. The following combinations of Uplink control information (UCI) are supported on PUCCH: z HARQ-ACK using PUCCH format 1a or 1b z Scheduling request (SR) using PUCCH format 1 z HARQ-ACK and SR using PUCCH format 1a or 1b z CQI/PMI or RI using PUCCH format 2 z CQI/PMI or RI and HARQ-ACK using PUCCH format – 2a or 2b for normal cyclic prefix – 2 for extended cyclic prefix
  • 65.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION PUCCH – ACK and CQI time ACK CQI
  • 66.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Sounding Reference Signals (SRS) SRS shall be transmitted at the last symbol of the subframe. PUSCH: • The mapping to resource elements only considers those not used for transmission of reference signals. PUCCH Format 1a and 1b (HARQ-ACK): • One SC-FDMA symbol on PUCCH shall be punctured. PUCCH Format 1 (SR) and 2, 2a, 2b (CQI): • A UE shall not transmit SRS whenever SRS collide with PUCCH format 1 (SR), and 2, 2a and 2b (CQI). Sounding Reference Signals Details about UE sounding procedure can be found in TS36.211 and TS36.213 §8.3. The reference signal sequence shall be multiplied with the amplitude scaling factor and mapped resource elements. The resource element mapping shall be in increasing order of first k, then l, and finally the slot number. There are many FDD sounding reference signal subframe configurations as per TS36.211 §5.5.3.3. The sounding reference signal shall be transmitted at the last symbol of the subframe according to 36.211. A UE shall not transmit SRS whenever SRS and CQI transmissions happen to coincide in the same subframe. A UE shall not transmit SRS whenever SRS and SR transmissions happen to coincide in the same subframe. When a UE is configured by higher layers to support both A/N and SRS transmissions in the same subframe, then the UE shall transmit A/N using a shortened PUCCH format where the A/N symbol corresponding to the SRS location is punctured.
  • 67.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION RA offset PRB n PRACH CP T SEQ T PRACH: • The preamble format determines the length of the Cyclic Prefix and Sequence • FDD has 4 preamble formats (for different cell sizes) and 16 RA slot configurations (for different bandwidth) • The start of Random Access Preamble transmission assumes Timing Advance = 0 except for handover that UE can assume a time difference between current cell and target cell • Each random access preamble occupies a bandwidth corresponding to 6 consecutive resource blocks • The diagram considers RACH structure for FDD PRACH The transmission of a random access preamble, if triggered by the MAC layer, is restricted to certain time and frequency resources. These resources are enumerated in increasing order of the subframe number within the radio frame and the physical resource blocks in the frequency domain such that index 0 correspond to the lowest numbered physical resource block and subframe within the radio frame. Note that cyclic prefix is extended to cope with large delay uncertainty (for different cell sizes). More information can be found in TS36.211 Section 5.7. Preamble format CP T SEQ T 0 s 3168 T ⋅ s 24576 T ⋅ 1 s 21024 T ⋅ s 24576 T ⋅ 2 s 6240 T ⋅ s 24576 2 T ⋅ ⋅ 3 s 21024 T ⋅ s 24576 2 T ⋅ ⋅ 4 (frame structure type 2 only) s 448 T ⋅ s 4096 T ⋅
  • 68.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Section Overview • SC-FDMA in E-UTRA Uplink Waveform • E-UTRA UL Channelization Hierarchy and Mapping • UL Physical Channels Resource Allocation • UL Operation Procedures Notes
  • 69.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Uplink Operation Highlights • Link Adaptation (CDS – Channel Dependent Scheduling) – Adaptive transmission Bandwidth – Adaptive Modulation and Channel Coding Rate (AMC) – Meets QoS requirements • UL Power Control – Intra-cell power control: the power spectral density of the Uplink transmissions can be influenced by the eNB. • UL Timing Control – Objective is to compensate for propagation delay and thus time-align the transmissions from different UEs with the receiver window of the eNB. – The timing advance is derived from the UL received timing and sent by the eNB to the UE. UE uses this information to advance/delay its timings of transmissions to the eNB. • Random Access procedure E-UTRA UL Operation Highlights Uplink link adaptation is used to guarantee the required minimum transmission performance of each UE such as the user data rate, packet error rate, and latency, while maximizing system throughput. Three types of link adaptation are performed according to the channel conditions, the UE capability such as the maximum transmission power and maximum transmission bandwidth, etc., and the required QoS such as the data rate, latency, and packet error rate, etc. Three link adaptation methods are as follows: z Adaptive transmission bandwidth z Transmission power control z Adaptive modulation and channel coding rate Uplink Power control: Intra-cell power control: the power spectral density of the Uplink transmissions can be influenced by the eNB. Uplink timing control z The timing advance is derived from the UL received timing and sent by the eNB to the UE. The UE uses this to advance/delay its timings of transmissions to the eNB to compensate for propagation delay and thus time-align the transmissions from different UEs with the receiver window of the eNB. z The timing advance command is on a per need basis with a granularity in the step size of 0.52 μs (16×Ts).
  • 70.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Uplink Operation Highlights (continued) Link Adaptation differences from HSPA: • Shared Channel Operation – Dedicated logical channels are mapped onto shared transport/physical channels • UL Multiple Access Dimensions: – frequency/time/space in LTE; code/time in HSPA • UL scheduler – Uplink time/frequency resources are monitored/managed at the E-NodeB. – HSPA, in contrast, monitors/manages Uplink Interference (Rise Over Thermal). – LTE scheduler assigns UL Time/Frequency resources, rather than UL TX Traffic/Pilot Ratios as in HSPA. – As in HSPA, Uplink scheduling is based on Scheduling Requests (SR), Buffer Status Report (BSR), and Power Headroom Reports (PHR). – It may coordinate with neighbor Base Stations for Interference management • Requires UL timing control to keep UL orthogonal E-UTRA UL Operation Highlights (continued) From TS36.201, transmissions with multiple input and multiple output antennas (MIMO) are supported with configurations in the Downlink with two or four transmit antennas and two or four receive antennas, which allow for multi-layer transmissions with up to four streams. Multi-user MIMO, i.e., allocation of different streams to different users, is supported in both UL and DL.
  • 71.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION • UE sends SR (Scheduling Request – part of Uplink Control Information), BSR (Buffer Status Report) and PHR (Power Headroom Report) on PUCCH (or starts random access if no PUCCH is configured). • Scheduler at E-NodeB dynamically allocates UL resources to UE: – Grant is assigned to UE on PDCCH. – Assigned resources (PRB and MCS) are communicated to the UE. • UE sends user data on PUSCH. • If E-Node B decodes the Uplink data successfully, it changes the New Data Indicator (NDI) on PDCCH, and/or sends ACK/NAKs on PHICH. PUCCH Physical Uplink Control Channel PDCCH Physical Downlink Control Channel PUSCH Physical Uplink Shared Channel PHICH Physical HARQ ACK/NAK Indicator Channel E-NodeB E-NodeB MME X1 PUSCH PHICH PUCCH IP Network X2 PDCCH E-UTRA UL Scheduled Operation (Link Adaptation) E-UTRA Uplink Scheduled Operation The following information is transmitted by means of the Downlink Control Information (DCI) format 0 on PDCCH for the scheduling of PUSCH: z Flag for format0/format1A differentiation z Hopping flag z Resource block assignment and hopping resource allocation z Modulation and coding scheme and redundancy version z New Data Indicator (NDI) z TPC command for scheduled PUSCH z Cyclic shift for DM RS z CQI request – 1 bit The details about grant value and its relationship to PUSCH power can be found in TS36.213 § 5.1.1.1. The UE ACK-NAK procedure is described in TS36.213 § 8.3. New Data Indicator (NDI) can be found in the Downlink Control Information (DCI) format 0 on PDCCH together with the Uplink scheduling assignment. HARQ ACK/NAKs are sent on the Downlink PHICH. Retransmissions shall be needed if the NDI has not changed or if PDCCH is not detected. Uplink Scheduling at E-Node B is based on: z Serving Cell Uplink Noise Rise (Rise-over-Thermal) z Overload Indicators from other E-Node Bs z UE Scheduling Requests (SR) z UE Buffer Status (BSR) z UE Power Headroom Report (PHR) z UE Capabilities
  • 72.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA User-Plane UL Data Transfer Functionality Split across Layers MAC-es/e Notes
  • 73.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION • UE transmits PUCCH or PUSCH. • Serving E-NodeB monitors link quality and takes into account the overload indicators (over X2) from neighbor cells. • Serving E-NodeB sends Transmit Power Control commands (TPC) as part of Downlink Control Information (DCI) on PDCCH. • UE adjusts transmit power levels of PUCCH or PUSCH. • Go back to 1. PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel PDCCH Physical Downlink Control Channel E-NodeB E-NodeB MME X1 PUSCH PUCCH IP Network X2 PDCCH PDSCH Overload Indicator Single Serving Cell No Soft Handover No Macro-diversity E-UTRA UL Closed Loop Power Control E-UTRA Uplink Closed Loop Power Control Uplink power control determines the average power over a DFT-SOFDM symbol in which the physical channel is transmitted. Uplink power control controls the transmit power of the different Uplink physical channels. A cell wide overload indicator (OI) is exchanged over X2 for inter-cell power control. DCI format 0 provides two bits of TPC command for PUSCH. DCI format 1, 1a and 2 provides two bits of TPC command for PUCCH. DCI format 3 is used for the transmission of TPC commands for PUCCH and PUSCH with 2-bit power adjustments. DCI format 3A is used for the transmission of TPC commands for PUCCH and PUSCH with single bit power adjustments.
  • 74.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Random Access •Random Access can be triggered by: • PDCCH order (i.e., handover) • UE MAC sublayer (i.e., initial access) •Two types of Random Access: • Synchronized: – The PDCCH order or RRC optionally indicate a Random Access Preamble and PRACH resource – When Random Access Preamble and PRACH resource are explicitly signaled, it is contention free • Unsynchronized – UE selects a Random Access Preamble and PRACH resource ‹ Select one of the two groups of Random Access Preambles configured by RRC ‹ Randomly select a Random Access Preamble within the selected group ‹ Contention resolution is needed E-UTRA Random Access More information can be found in TS36.321 Section 5.1.
  • 75.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION E-UTRA Synchronized Random Access •The E-UTRA Random Access procedure is specified mainly in the MAC layer only! Preamble Initial Received Target Power Power Ramp Step Preamble Received Target Power … MAC (Layer 2) PHY (Layer 1) Power Ramp Step Preamble Transmission Counter 1 2 3 … Time Random Access Response (on PDCCH assoc with RA-RNTI) TTI Window + Backoff Random Access Preamble Identifier Match Random Access procedure successfully completed [TTI Window] ≤ Preamble Trans Max • Timing Advance / Alignment (TA) value • Uplink grant value • Temporary C- RNTI E-UTRA Synchronized Random Access Before the random access procedure can be initiated, the following information is assumed to be available: z - the available set of PRACH resources for the transmission of the Random Access Preamble and their corresponding RA-RNTIs. z - the groups of Random Access Preambles and the set of available Random Access Preambles in each group. – There are 64 preambles available in each cell. z - the thresholds required for selecting one of the two groups of Random Access Preambles. z - the parameters required to derive the TTI window [RA_Window_Begin – RA_Window_End]. z - the power-ramping factor POWER_RAMP_STEP. z - the parameter PREAMBLE_TRANS_MAX [integer > 0]. z - the initial preamble power PREAMBLE_ INITIAL_RECEIVED_TARGET_POWER. z - the parameter Maximum number of Message3 HARQ transmissions. Note that the diagram above is only for illustration of the random access sequence, and the exact transmission timing of the random access preamble should be determined according to the selection of the PRACH resources (specified in time and frequency domain) as per TS36.321 Section 5.1.2. E-UTRA Random Access Response More information can be found in TS36.321 Section 5.1.4. Once the Random Access Preamble is transmitted, the UE shall monitor the PDCCH associated with the RA-RNTI defined below in the TTI window [RA_WINDOW_BEGIN—RA_WINDOW_END] for Random Access Responses identified by the RA-RNTI.
  • 76.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Cell Switching (1/2) Only one serving cell per UE ƒ Same for UL and DL »UE does not receive DL data or UL ACKs from multiple cells ƒ UE cannot transmit to multiple cells with single Tx chain in asynchronous deployments »Single carrier waveform in uplink L2 handover ƒ Network based » UE assisted ƒ UE based »UE performs HO autonomously
  • 77.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION Comments/Notes
  • 78.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION 5 SECTION What is Next? Notes
  • 79.
    Long Term Evolution(LTE/FDD) Fundamentals 80-W1738-1 Rev A © 2008 QUALCOMM Incorporated MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION LTE Advanced LTE Targets (3GPP TS25.913) LTE Advanced Targets (3GPP TR36.913) Latency • U-plane latency: < 5 ms (unloaded) • C-plane latency: ƒ < 100 ms from Idle to Active ƒ < 50 ms from Dormant to Active Data Rate • DL peak rate: ƒ 100 Mbps (20 MHz) • UL peak rate: ƒ 50 Mbps (20 MHz) Latency •U-plane latency: lower than LTE •C-plane latency: ƒ < 50 ms from Idle to Active ƒ < 10 ms from Dormant to Active Data Rate • DL peak rate: ƒ Low mobility: 1 Gbps ƒ High mobility: 100 Mbps • UL peak rate: 500 Mbps Spectrum Efficiency • DL: 3-4 X 3GPP Release 6 • UL: 2-3 X 3GPP Release 6 Scalable Bandwidth 1.25 to 20 MHz Extend Bandwidth Scalability up to 100 MHz Spectrum Efficiency • DL: Peak: 30 bps/Hz ƒ Avg: 2.4 - 3.7 bps/Hz ƒ Cell Edge: 0.07 – 0.12 bps/Hz • UL: Peak: 15 bps / Hz ƒ Avg: 1.2 - 2.0 bps/Hz ƒ Cell Edge: 0.04 – 0.07 bps/Hz June 2008 LTE Advanced LTE requirements are described in 3GPP TR25.913, while LTE Advanced requirements are described in 3GPP TR36.913. Note that all minimum requirements for UTRA found in TR25.913 would apply to E-UTRA / LTE if not described in TR36.913.