Arief Hamdani Gunawan1. Introduction to LTE 5. LTE Radio Procedures2. OFDMA 6. LTE Uplink Physical Channels and Signals3. SC-FDMA SC- 7. LTE Mobility4. LTE Network and Protocol 8. LTE Test and Measurement
Arief Hamdani Gunawan
Session 1: Introduction to LTE•Motivation•Requirements•Evolution of UMTS FDD and TDD•LTE Technology Basics•LTE Key Parameters•LTE Frequency Bands
Motivation: LTE background story the early days Work on LTE was initiated as a 3GPP release 7 study item “Evolved UTRA and UTRAN” in December 2004: “With enhancements such as HSDPA and Enhanced Uplink, the 3GPP radio-access technology will be highly competitive for several years. However, to ensure competitiveness in an even longer time frame, i.e. for the next 10 years and beyond, a long term evolution of the 3GPP radio- access technology needs to be considered.”• Basic drivers for LTE have been: – Reduced latency – Higher user data rates – Improved system capacity and coverage – Cost-reduction.
Major requirements for LTE identified during study item phase in 3GPP• Higher peak data rates: 100 Mbps (downlink) and 50 Mbps (uplink)• Improved spectrum efficiency: 2-4 times better compared to 3GPP release 6• Improved latency: – Radio access network latency (user plane UE – RNC - UE) below 10 ms – Significantly reduced control plane latency• Support of scalable bandwidth: 1.4, 3, 5, 10, 15, 20 MHz• Support of paired and unpaired spectrum (FDD and TDD mode)• Support for interworking with legacy networks• Cost-efficiency: – Reduced CApital and OPerational EXpenditures (CAPEX, OPEX) including backhaul – Cost-effective migration from legacy networks• A detailed summary of requirements has been captured in 3GPP TR 25.913 „Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E- UTRAN)”.
Evolution of UMTS FDD and TDD driven by data rate and latency requirementsNote:•High-Speed Downlink Packet Access (HSDPA, also known as High-Speed Data Packet Access)•High-Speed Uplink Packet Access (HSUPA)•High Speed Packet Access (HSPA)
3GPP SystemsBuilding on Releases
Release 99: Key Features• Functional Freeze: Dec 1999 – CS and PS – R99 Radio Bearers – Multimedia Messaging Service (MMS) – Location Services• Functional Freeze: March 2000 – Basic 3.84 Mcps W-CDMA (FDD & TDD)• Enhancements to GSM data (EDGE).• Provides support for GSM/EDGE/GPRS/WCDMA radio-access networks.• Majority of deployments today are based on Release 99.
Release 4: Key Features • Functional Freeze: March 2001 – Enhancements 1.28 Mcps TDD (aka TD-SCDMA). – Multimedia messaging support. – First steps toward using IP transport in the core network.Megachips per second (Mcps) is a measure of the speed with which encoding elements,called chips (not to be confused with microchips), are generated in Direct Sequence SpreadSpectrum (DSSS) signals. This speed is also known as the chipping rate. A speed of 1 Mcps isequivalent to 1,000,000, or 106, chips per second.Typical chipping rates in third-generation (3G) wireless systems are on the order of severalmillion chips per second. For example, in Wideband Code-Division Multiple Access (W-CDMA)systems, the standard rate is 3.84 Mcps.
Release 5: Key Features • Functional Freeze: June 2002 – HSDPA – IMS: First phase of Internet Protocol Multimedia Subsystem (IMS). – Adaptive Multi-Rate - Wideband (AMR-WB) Speech – Full ability to use IP-based transport instead of just Asynchronous Transfer Mode (ATM) in the core network.Adaptive Multi-Rate Wideband (AMR-WB) is a patented speech coding standard developedbased on Adaptive Multi-Rate encoding, using similar methodology as Algebraic Code ExcitedLinear Prediction (ACELP). AMR-WB provides improved speech quality due to a wider speechbandwidth of 50–7000 Hz compared to narrowband speech coders which in general areoptimized for POTS wireline quality of 300–3400 Hz. AMR-WB was developed by Nokia andVoiceAge and it was first specified by 3GPP.AMR-WB is codified as G.722.2, an ITU-T standard speech codec, formally known as Widebandcoding of speech at around 16 kbit/s using Adaptive Multi-Rate Wideband (AMR-WB). G.722.2AMR-WB is the same codec as the 3GPP AMR-WB. The corresponding 3GPP specifications are TS26.190 for the speech codec and TS 26.194 for the Voice Activity Detector.
3GPP architecture evolution towards flat architecture Release 6 Release 7 Release 7 Release 8 Direct Tunnel Direct Tunnel and SAE and LTE RNC in NB GGSN GGSN GGSN SAE GW SGSN SGSN SGSN MME RNC RNC NB NB RNC eNB NB Control Plane User Plane
Release 6: Key Features• Functional Freeze: March 2005 – HSUPA (E-DCH) / Enhanced Uplink – Enhanced multimedia support through Multimedia Broadcast/Multicast Services (MBMS). – WLAN-UMTS Internetworking: Wireless Local Area Network (WLAN) integration option – Performance specifications for advanced receivers. – IMS enhancements. Initial VoIP capability.
Release 7: Key Features• Functional Freeze: Dec 2007 – Evolved EDGE. – Specifies HSPA+ – Radio enhancements to HSPA include 64 Quadrature Amplitude Modulation (QAM) in the downlink DL and 16 QAM in the uplink. – LTE and SAE Feasibility Study – DL MIMO, – IMS – Performance enhancements, improved spectral efficiency, increased capacity, and better resistance to interference. – Continuous Packet Connectivity (CPC) enables efficient “always-on” service and enhanced uplink UL VoIP capacity, as well as reductions in call set-up delay for Push-to-Talk Over Cellular (PoC). – Optimization of MBMS capabilities through the multicast/broadcast, single-frequency network (MBSFN) function.
LTE Release 8: Key Features• Functional Freeze: Dec 2008 – Further HSPA improvements / HSPA Evolution, simultaneous use of MIMO and 64 QAM. – Includes dual-carrier HSPA (DC-HSPA) where in two WCDMA radio channels can be combined for a doubling of throughput performance. – LTE work item – OFOMA / SC-FDMA air interface – SAE work item – new IP core network – Specifies OFDMA-based 3GPP LTE. – Defines EPC.
LTE Release 8: Key Features• High spectral efficiency – OFDM in Downlink • Robust against multipath interference • High affinity to advanced techniques – Frequency domain channel-dependent scheduling – MIMO – DFTS-OFDM(“Single-Carrier FDMA”) in Uplink • Low PAPR DFTS-OFDM • User orthogonality in frequency domain DFTS-OFDM: DFT-spread OFDM. – Multi-antenna application DFT: Discrete Fourier Transform.• Very low latency – Short setup time & Short transfer delay DFT-spread OFDM (DFTS-OFDM) is a transmission – Short HO latency and interruption time scheme that can combine the desired properties • Short TTI for uplink transmission i.e. : • RRC procedure • Small variations in the instantaneous power of the transmitted signal (‘single carrier’ property). • Simple RRC states • Possibility for low-complexity high-quality• Support of variable bandwidth equalization in the frequency domain. – 1.4, 3, 5, 10, 15 and 20 MHz • Possibility for FDMA with flexible bandwidth assignment. Due to these properties, DFTS-OFDM has been selected as the uplink transmission scheme for LTE, which is the long-term 3G evolution.
LTE-Advanced: Key RequirementsLTE-Advanced shall be deployed as an evolution of LTE Release 8 and on newbands.LTE-Advanced shall be backwards compatible with LTE Release 8 Smooth and flexible system migration from Rel-8 LTE to LTE-Advanced LTE-Advanced backward compatibility with LTE Rel-8 LTE-Advanced contains all features of LTE Rel-8&9 and additional features for further evolution LTE Rel-8 cell LTE-Advanced cell LTE Rel-8 terminal LTE-Advanced terminal LTE Rel-8 terminal LTE-Advanced terminal An LTE-Advanced terminal An LTE Rel-8 terminal can can work in an LTE Rel-8 cell work in an LTE-Advanced cell
LTE Release 9: Key Features• Small enhancements from LTE Release 8 mainly for higher layer – HeNB (Home eNode B) • HeNB Access Mode – Rel-8: Closed Access Mode – Rel-9: Open and Hybrid Mode • HeNB Mobility between HeNB and macro – Rel-8: Out-bound HO – Rel-9: in-bound and inter-CSG HO – SON (self-organizing networks) • Rel-8: Self configuration, Basic self-optimization • Rel-9: RACH optimization, etc – MBMS (Multimedia Broadcast Multicast Service) • Rel-8: Radio physical layer specs • Rel-9: Radio higher layer and NW interface specs – LCS (Location Services) • Rel-8: U-Plane solutions • Rel-9: C-Plane solutions, e.g. OTDOA
LTE Release 9: Key Features• HSPA and LTE enhancements including – HSPA dual-carrier operation in combination with MIMO, – EPC enhancements, – femtocell support, – support for regulatory features such as emergency user-equipment positioning and Commercial Mobile Alert System (CMAS), and – evolution of IMS architecture.
LTE-Advanced: Motivation 1999 2011Release 99 W-CDMA 3GPP aligned to ITU-R IMT process Release 4 1.28Mcps TDD Allows Coordinated approach to WRC Release 5 HSDPA 3GPP Releases evolve to meet: • Future Requirements for IMT Release 6 HSUPA, MBMS • Future operator and end-user requirements ITU-R M.1457 Release 7 HSPA+ (MIMO, HOM etc.) IMT-2000 Recommendation Release 8 LTE Release 9 LTE enhancements 3 Gbps ITU-R M.[IMT.RSPEC] Release 10 LTE-Advanced 64QA IMT-Advanced Recommendation M Release 11+ Further LTE enhancements 8x8 MIMO 100MHz BW
LTE Release 10: Key Features 100 MHz Support of Wider Bandwidth(Carrier Aggregation) • Use of multiple component carriers(CC) to extend bandwidth up to 100 MHz • Common physical layer parameters between component carrier and LTE Rel-8 carrier f Improvement of peak data rate, backward compatibility with LTE Rel-8 CC Advanced MIMO techniques • Extension to up to 8-layer transmission in downlink • Introduction of single-user MIMO up to 4-layer transmission in uplink • Enhancements of multi-user MIMO Improvement of peak data rate and capacity Heterogeneous network and eICIC(enhanced Inter-Cell Interference Coordination) • Interference coordination for overlaid deployment of cells with different Tx power Improvement of cell-edge throughput and coverage Relay • Type 1 relay supports radio backhaul and creates a separate cell and appear as Rel. 8 LTE eNB to Rel. 8 LTE UEs Improvement of coverage and flexibility of service area extension Coordinated Multi-Point transmission and reception (CoMP) • Support of multi-cell transmission and reception Improvement of cell-edge throughput and coverageLTE-Advanced meeting the requirements set by ITU’s IMT-Advanced project.Also includes quad-carrier operation for HSPA+.
Spectrum Explosion in 3GPP Recently standardized (Sep. 2011)E-UTRA operating bands in 3GPP TS 36.101 • UMTS/LTE 3500MHz • Extending 850 MHz Upper Band (814 – 849 MHz) Spectrum to be standardized by Sep. 2012 • LTE-Advanced Carrier Aggregation of Band 3 and Band 7 • LTE Advanced Carrier Aggregation of Band 4 and Band 17 • LTE Advanced Carrier Aggregation of Band 4 and Band 13 • LTE Advanced Carrier Aggregation of Band 4 and Band 12 • LTE Advanced Carrier Aggregation of Band 5 and Band 12 • LTE Advanced Carrier Aggregation of Band 20 and Band 7 • LTE Advanced Carrier Aggregation Band 2 and Band 17 • LTE Advanced Carrier Aggregation Band 4 and Band 5 • LTE Advanced Carrier Aggregation Band 5 and Band 17 • LTE Advanced Carrier Aggregation in Band 41 • LTE Advanced Carrier Aggregation in Band 38 • LTE Downlink FDD 716-728MHz • LTE E850 - Lower Band for Region 2 (non-US) • LTE for 700 MHz digital dividend • Study on Extending 850MHz • Study on Interference analysis between 800~900 MHz bands • Study on UMTS/LTE in 900 MHz band
E-UTRA operating bands Duplex Mode: FDD
E-UTRA operating bands Duplex Mode: TDD
3GPP TS 36.101 Evolved Universal Terrestrial Radio Access (E-UTRA);User Equipment (UE) radio transmission and reception
3GPP TS 36.101 Evolved Universal Terrestrial Radio Access (E-UTRA);User Equipment (UE) radio transmission and reception
The 2.6GHz band 120MHz separation duplex FDD Uplink TDD FDD Downlink 2500 2570 2620 2690 MHz Capacity• Unique new band internationally harmonized• Benefits of future economies of scale• Capability to offer sufficient bandwidth per operator (20+20MHz)• Avoid prejudicial interference, optimizing the spectrum use, through clear definition of FDD (70+70MHz) and TDD (50MHz) spectrum blocks
700MHz band 748 758 803 703 698 806 MHz 5 45 10 45 3 Coverage• Perfect fit to majority of countries in the region• The alignment with Asia-Pacific permits the creation of a big market (economies of scale, availability of terminals, etc.)• Offer 2 continuous blocks of 45+45MHz (spectrum optimization, flexibility on license process, better data transmission performance than US 700);• Tool to bring the mobile broadband to rural and low density population areas
2.6GHz + 700MHz• Ideal combination for – Coverage – Capacity – Convergence – Device availability – Roaming• Convergence for countries with the legacy US band plan (850/1900MHz) and the legacy European band plan (900/1800MHz)• Note: no plans/proposals in 3GPP for LTE in 450Mhz band
LTE Release 11: Key Features (Dec/2012) Further Downlink MIMO enhancements for LTE-Advanced Addressing low-power modes, relay backhaul scenarios, and certain practical antenna configurations Provision of low-cost M2M UEs based on LTE Studying LTE Coverage Enhancements Network-Based Positioning Support for LTE Further Self Optimizing Networks (SON) Enhancements Mobility Robustness Optimisation (MRO) enhancements Addressing Inter-RAT ping-pong scenarios Carrier based HetNet Interference co-ordination for LTE Carriers in same or different bands in HetNet environments with mixture of different BTS types Enhancements to Relays, Mobile Relay for LTE RF core requirements for relays Mobile relay: mounted on a vehicle wirelessly connected to the macro cellsInterworking - 3GPP EPS and fixed BB accesses, M2M, Non voice emergency communications, 8 carrierHSDPA, Uplink MIMO study
RAN Release 11 Priorities • Short term prioritization for the end of 2011, between RAN#53 and RAN#54 • The next Plenary - RAN#54 (Dec. 2011) – will discuss priorities beyond March 2012 Latest RANH S P A Priority Work Items; WID/SID Working GroupCore part: Uplink Transmit Diversity for HSPA – Closed Loop RP-110374 RAN 1New WI: Four Branch MIMO transmission for HSDPA RP-111393 RAN 1Core Part: eight carrier HSDPA RP-101419 RAN 1Core part: Further Enhancements to CELL_FACH RP-111321 RAN 2New WI: HSDPA Multiflow Data Transmission RP-111375 RAN 2Proposed WID: Single Radio Voice Call Continuity from UTRAN/GERAN to E-UTRAN/HSPA RP-111334 RAN 3Core part: Non-contiguous 4C-HSDPA operation RP-110416 RAN 4New SID proposal: Introduction of Hand phantoms for UE OTA antenna testing RP-111380 RAN 4Core part: Uplink Transmit Diversity for HSPA – Open Loop RP-110374 RAN 4UE Over the Air (Antenna) conformance testing methodology- Laptop Mounted Equipment Free Space test RP-111381 RAN 4
RAN Release 11 Priorities Latest RANL T E Priority Work Items; WID/SID Working GroupWI/SI Coordinated Multi-Point Operation for LTE RP-111365 RAN 1Core part: LTE Carrier Aggregation Enhancements RP-111115 RAN 1Core part: Further Enhanced Non CA-based ICIC for LTE RP-111369 RAN 1Study on further Downlink MIMO enhancements for LTE-Advanced RP-111366 RAN 1Provision of low-cost MTC UEs based on LTE RP-111112 RAN 1Proposed SI on LTE Coverage Enhancements RP-111359 RAN 1Core part: LTE RAN Enhancements for Diverse Data Applications RP-111372 RAN 2Study on HetNet mobility enhancements for LTE RP-110709 RAN 2Enhancement of Minimization of Drive Tests for E-UTRAN and UTRAN RP-111361 RAN 2New WI: Signalling and procedure for interference avoidance for in-device coexistence RP-111355 RAN 2New WI proposal: RAN overload control for Machine-Type Communications RP-111373 RAN 2Core part: Service continuity and location information for MBMS for LTE RP-111374 RAN 2Core Part: Network-Based Positioning Support for LTE RP-101446 RAN 2Further Self Optimizing Networks (SON) Enhancements RP-111328 RAN 3Core part: Carrier based HetNet ICIC for LTE RP-111111 RAN 3New WI: Network Energy Saving for E-UTRAN RP-111376 RAN 3Proposed WID: LIPA Mobility and SIPTO at the Local Network RAN Completion RP-111367 RAN 3Study on further enhancements for HNB and HeNB RP-110456 RAN 3New SI: Mobile Relay for E-UTRA RP-111377 RAN 3Enhanced performance requirement for LTE UE RP-111378 RAN 4New SI: Study of RF and EMC Requirements for Active Antenna Array System (AAS) Base Station RP-111349 RAN 4Study on Measurement of Radiated Performance for MIMO and multi-antenna reception for HSPA and LTE terminals RP-090352 RAN 4New WI: E-UTRA medium range and MSR medium range/local area BS class requirements RP-111383 RAN 4Core part: Relays for LTE (part 2) RP-110914 RAN 4Study on Inclusion of RF Pattern Matching Technologies as a positioning method in the E-UTRAN RP-110385 RAN 4
Plans for LTE-A Release-12• 3GPP workshop to be held June/2012 – Main themes and strategic directions to be set, e.g.: • Extreme capacity needs and spectrum efficiency (‘challenge Shannon’ • Flexibility, efficient handling of smartphone diversity • Offloading to unlicensed radio technologies • Power efficiency• Prime areas of interest, e.g.: – More optimized small cell deployments – Carrier Aggregation Enhancements (inter-site, LTE/HSPA) – Cognitive radio aspects – SON and MDT enhancements – Local Area optimizations
LTE Key Parameters
Session 2: OFDMA•OFDM and OFDMA•LTE Downlink•OFDMA time-frequency multiplexing•LTE Spectrum Flexibility•LTE Frame Structure type 1 (FDD)•LTE Frame Structure type 2(TDD)
OFDM• Single Carrier Transmission (e.g. WCDMA)• Orthogonal Frequency Division Multiplexing
OFDM Concept: Mengapa OFDM• Sinyal OFDM (Orthogonal Frequency Division Multiplexing) dapat mendukung kondisi NLOS (Non Line of Sight) dengan mempertahankan efisiensi spektral yang tinggi dan memaksimalkan spektrum yang tersedia.• Mendukung lingkungan propagasi multi-path.• Scalable bandwidth: menyediakan fleksibilitas dan potensial mengurangi CAPEX (capital expense). 36
OFDM Concept: NLOS Performance 37
OFDM Concept: Mutipath Propagation• Sinyal-sinyal multipath datang pada waktu yang berbeda dengan amplitudo dan pergeseran fasa yang berbeda, yang menyebabkan pelemahan dan penguatan daya sinyal yang diterima.• Propagasi multipath berpengaruh terhadap performansi link dan coverage.• Selubung (envelop) sinyal Rx berfluktuasi secara acak. 38
OFDM Concept: FFT• Multi-carrier modulation/multiplexing technique• Available bandwidth is divided into several subchannels• Data is serial-to-parallel converted• Symbols are transmitted on different subcarriers 39
OFDM Concept: IFFTBasic ideas valid for various multicarrier techniques:• OFDM: Orthogonal Frequency Division Multiplexing• OFDMA: Orthogonal Frequency Division Multiple Access 40
OFDM Concept: Single-Carrier Vs. OFDM Single-Carrier Mode: OFDM Mode:• Serial Symbol Stream Used to Modulate a • Each Symbol Used to Modulate a Separate Single Wideband Carrier Sub-Carrier• Serial Datastream Converted to Symbols (Each Symbol Can Represented 1 or More Data Bits) 41
OFDM Concept: Single-Carrier Vs. OFDM Single-Carrier Mode OFDM Mode• Dotted Area Represents Transmitted Spectrum• Solid Area Represents Receiver Input• OFDM mengatasi delay spread, multipath dan ISI (Inter Symbol Interference) secara efisien sehingga dapat meningkatkan throughput data rate yang lebih tinggi.• Memudahkan ekualisasi kanal terhadap sub-carrier OFDM individual, dibandingkan terhadap sinyal single-carrier yang memerlukan teknik ekualisasi adaptif lebih kompleks. 42
OFDM Concept: Motivation for Multi-carrier Approaches• Multi-carrier transmission offers various advantages over traditional single carrier approaches: – Highly scalable – Simplified equalizer design in the frequency domain, also in cases of large delay spread – High spectrum density – Simplified the usage of MIMO – Good granularity to control user data rates – Robustness against timing errors• Weakness of multi-carrier systems: – Increased peak to average power ratio (PAPR) – Impairments due to impulsive noise – Impairments due to frequency errors 43
OFDM Concept: Peak to Average Power Ratio (PAPR)• PAPR merupakan ukuran dari fluktuasi tepat sebelum amplifier.• PAPR sinyal hasil dari mapping PSK base band sebesar 0 dB karena semua symbol mempunyai daya yang sama.• Tetapi setelah dilakukan proses IDFT/IFFT, hasil superposisi dari dua atau lebih subcarrier dapat menghasilkan variasi daya dengan nilai peak yang besar.• Hal ini disebabkan oleh modulasi masing-masing subcarrier dengan frekuensi yang berbeda sehingga apabila beberapa subcarrier mempunyai fasa yang koheren, akan muncul amplituda dengan level yang jauh lebih besar dari daya sinyalnya. 44
OFDM Concept: Peak to Average Power Ratio (PAPR)• Nilai PAPR yang besar pada OFDM membutuhkan amplifier dengan dynamic range yang lebar untuk mengakomodasi amplitudo sinyal.• Jika hal ini tidak terpenuhi maka akan terjadi distorsi linear yang menyebabkan subcarrier menjadi tidak lagi ortogonal dan pada akhirnya menurunkan performansi OFDM. 45
Tipe Sub-Carrier OFDMData Sub-carriers• Membawa simbol BPSK, QPSK, 16QAM, 64QAMPilot Sub-carriers• Untuk memudahkan estimasi kanal dan demodulasi koheren pada receiver.Null Subcarrier• Guard Sub-carriers• DC Sub-carrier 46
Guard Interval (Cyclic Prefix)• Untuk mengatasi multipath delay spread 47• Guard Interval (cyclic prefix) : 1/4, 1/8, 1/16 or 1/32
OFDM Transceiver 48
OFDM & OFDMAOFDM OFDMA• Semua subcarrier dialokasikan untuk satu • Subcarrier dialokasikan secara fleksibel user untuk banyak user tergantung pada kondisi• Misal : 802.16-2004 radio. • Misal : 802.16e-2005 dan 802.16m 49
OFDM Parameters used in WiMAX 50
Difference between OFDM and OFDMA• OFDM allocates users in time • OFDMA allocates users in time domain only and frequency domain
OFDMA time-frequency multiplexing
LTE Downlink Physical Layer Design: Physical Resource The physical resource can be seen as a time-frequency grid• LTE uses OFDM (Orthogonal Frequency Division Multiplexing) as its radio technology in downlink• In the uplink LTE uses a pre=coded version of OFDM, SC-FDMA (Single Carrier Frequency Division Multiple Access) to reduced power consumption 53
LTE Downlink Resource Grid • Suatu RB (resource block) terdiri dari 12 subcarrier pada suatu durasi slot 0.5 ms. • Satu subcarrier mempunyai BW 15 kHz, sehingga menjadi 180 kHz per RB. 54
Parameters for DL generic frame structure Bandwidth (MHz) 1.25 2.5 5.0 10.0 15.0 20.0 Subcarrier bandwidth (kHz) 15 Physical resource block (PRB) 180 bandwidth (kHz) Number of available PRBs 6 12 25 50 75 100 55
Parameters for DL generic frame structure Transmission BW 1.25 MHz 2.5 MHz 5 MHz 10 MHz 15 MHz 20 MHz Sub-frame duration 0.5 ms Sub-carrier spacing 15 kHz 192 MHz 7.68 MHz 15.36 MHz 23.04 MHz 30.72 MHz Sampling frequency (1/2x3.84 3.84 MHz (2x3.84 MHz) (4x3.84 MHz) (6x3.84 MHz) (8x3.84 MHz) MHz) FFT size 128 256 512 1024 1536 2048 OFDM sym per slot 7/6 (short/long CP) (4.69/9) x 6, (4.69/18) x 6, (4.69/36) x 6, (4.69/72) x 6, (4.69/108) x 6, (4.69/144) x 6, ShortCP length (5.21/10) x 1 (5.21/20) x 1 (5.21/40) x 1 (5.21/80) x 1 (5.21/120) x 1 (5.21/160) x 1 (usec/samples) Long (16.67/32) (16.67/64) (16.67/128) (16.67/256) (16.67/384) (16.67/512) 56
LTE – Spectrum Flexibility• LTE physical layer supports any bandwidth from 1.4 MHz to 20 MHz in steps of 180 kHz (resource block).• Current LTE specification supports a subset of 6 different system bandwidths.• All UEs must support the maximum bandwidth of 20 MHz.
E-UTRA channel bandwidth
Case Study LTE Signal Spectrum (20 MHz case)• The LTE standard uses an over-sized LTE. The actual used bandwidth is controlled by the number of used subcarriers. 15 kHz subcarrier spacing is the constant factor!• 18 MHz out of 20 MHz is used for data, 1 MHz on each side is used as guard band.• LTE used spectrum radio = 90%• WiMAX used spectrum radio = 82% 59
TDD & FDD• Time Division Duplex (TDD)• Frequency Division Duplex (FDD)• Durasi Frame : 2.5 - 20ms 60
Generic LTE Frame Structure type 1 (FDD) Tf = 307200 x Ts = 10 ms Tslot = 15360 x Ts = 0.5 ms• Untuk struktur generik, frame radio 10 ms dibagi dalam 20 slot yang sama berukuran 0.5 ms.• Suatu sub-frame terdiri dari 2 slot berturut-turut, sehingga satu frame radio berisi 10 sub-frame.• Ts menunjukkan unit waktu dasar yang sesuai dengan 30.72 MHz.• Struktur frame tipe-1 dapat digunakan untuk transmisi FDD dan TDD. 61
LTE Frame Structure type 1 (FDD)• 2 slots form one subframe = 1 ms• For FDD, in each 10 ms interval, all 10 subframes are available for downlink transmission and uplink transmissions.• For TDD, a subframe is either located to downlink or uplink transmission. The 0th and 5th subframe in a radio frame is always allocated for downlink transmission. 62
Downlink LTE Frame Structure type 1 (FDD)
Generic LTE Frame Structure type 2 (TDD)• Struktur frame tipe-2 hanya digunakan untuk transmisi TDD.• Slot 0 dan DwPTSdisediakan untuk transmisi DL, sedangkan slot 1 dan UpPTS disediakan untuk transmisi UL. 64
LTE Frame Structure type 2 (TDD) 65
Mobile WiMAX Frame Structure 66
LTE Frame Structure type 2 (TDD)
DL Peak rates for E-UTRA FDD/TDD frame structure type 1 Downlink 64 QAMAssumptions Signal overhead for reference signals and control channel occupying one OFDM symbolUnit Mbps in 20 MHz b/s/HzRequirement 100 5.02x2 MIMO 172.8 8.64x4 MIMO 326.4 16.3
UL Peak rates for E-UTRA FDD/TDD frame structure type 1 Uplink Single TX UEAssumptions Signal overhead for reference signals and control channel occupying 2RBUnit Mbps in 20 MHz b/s/HzRequirement 50 2.516QAM 57.6 2.964QAM 86.4 4.3
Peak rates for E-UTRA TDD frame structure type 2 Downlink Uplink Single TX UE, Assumptions 64 QAM, R=1 64 QAM, R=1 Mbps Mbps Unit b/s/Hz b/s/Hz in 20 MHz in 20 MHz Requirement 100 5.0 50 2.52x2 MIMO in DL 142 7.1 62.7 3.14x4 MIMO in DL 270 13.5
3GPP TR 25.912 Technical Specification Group Radio Access Network; Feasibility study for evolved Universal Terrestrial Radio Access (UTRA) and Universal Terrestrial Radio Access Network (UTRAN)Release Freeze meeting Freeze date ::Rel-7 RP-33 2006-09-22 :: event version available RP-27 0.0.0 2005-03-03 RP-31 0.0.4 2006-03-20 draft 0.1.0 2006-03-20 draft 0.1.1 2006-03-20 post RP-31 0.1.2 2006-03-30 R3-51b 0.1.3 2006-05-02 draft post Shanghai 0.1.4 2006-05-22 draft 0.1.5 2006-07-10 draft 0.1.6 - draft 0.1.7 2006-05-29 RP-32 0.2.0 2006-06-12 RP-32 7.0.0 2006-06-23 RP-33 7.1.0 2006-10-18 RP-36 7.2.0 2007-08-13
3GPP TR 25.912 Technical Specification Group Radio Access Network; Feasibility study for evolved Universal Terrestrial Radio Access (UTRA) and Universal Terrestrial Radio Access Network (UTRAN)Rel-8 SP-42 2008-12-11 :: . ETSI event version available remarks RTR/TSGR- SP-42 8.0.0 2009-01-02 Upgraded unchanged from Rel-7 0025912v800 Upgraded to Rel-9 with no technical change to enableRel-9 SP-46 2009-12-10 :: reference related to ITU-R IMT-Advanced submission ETSI (reference in 36.912). . event version available remarks RTR/TSGR- RP-45 9.0.0 2009-10-01 Technically identical to v8.0.0 0025912v900 Upgraded from previous Release without technicalRel-10 SP-51 2011-03-23 :: ETSI change . event version available remarks RTR/TSGR- SP-51 10.0.0 2011-04-06 Automatic upgrade from previous Release version 9.0.0 0025912va00 Upgraded from previous Release without technicalRel-11 SP-57 2012-09-12 :: ETSI change . event version available remarks SP-57 11.0.0 2012-09-26 Automatic upgrade from previous Release version 10.0.0 -
Session 3: SC-FDMA•Introduction SC-FDMA and UL frame structure•How to generate SC-FDMA•How does SC-FDMA signal look like•SC-FDMA Signal Generation•SC-FDMA PAPR•SC-FDMA Parameterization
LTE Uplink Transmission Scheme: SC-FDMA• Pemilihan OFDMA dianggap optimum untuk memenuhi persyaratan LTE pada arah downlink, tetapi OFDMA memiliki properti yang kurang menguntungkan pada arah Uplink.• Hal tsb terutama disebabkan oleh lemahnya peak-to-average power ratio (PAPR) dari sinyal OFDMA, yang mengakibatkan buruknya coverage uplink.• Oleh karena itu, skema transmisi Uplink LTE untuk mode FDD maupun TDD didasarkan pada SC-FDMA, yang mempunyai properti PAPR lebih baik.• Pemrosesan sinyal SC-FDMA memiliki beberapa kesamaan dengan pemrosesan sinyal OFDMA, sehingga parameter-parameter DL dan UL dapat diharmonisasi.• Untuk membangkitkan sinyal SC-FDMA, E-UTRA telah memilih DFT- spread-OFDM (DFT-s-OFDM). 74
OFDMA and SC-FDMA • The symbol mapping in OFDM happens in the frequency domain. • In SC-FDMA, the symbol mapping is done in the time domain. • Appropriate subscriber mapping in the frequency domain allows to control the PAPR. • SC-FDMA enable frequency domain equalizer approaches like OFDMA 75
Comparison of how OFDMA and SC-FDMAtransmit a sequence of QPSK data symbols 76
Comparison of how OFDMA and SC-FDMAtransmit a sequence of QPSK data symbols Creating the time- domain waveform of an SC-FDMA symbol Baseband and shifted frequency domain representations of an SC-FDMA symbol 77
How to generate SC-FDMA?• DFT “pre-coding” is performed on modulated data symbols to transform them into frequency domain,• Sub-carrier mapping allows flexible allocation of signal to available sub-carriers,• IFFT and cyclic prefix (CP) insertion as in OFDM,• Each subcarrier carries a portion of superposed DFT spread data symbols, therefore SC-FDMA is also referred to as DFT-spread- OFDM (DFT-s-OFDM).
How does a SC-FDMA signal look like?• Similar to OFDM signal, but… – …in OFDMA, each sub-carrier only carries information related to one specific symbol, – …in SC-FDMA, each sub-carrier contains information of ALL transmitted symbols.
SC-FDMA signal generationLocalized vs. distributed FDMA
SC-FDMA – Peak-to-average Power Ratio (PAPR) Comparison of CCDF of PAPR for IFDMA, LFDMA, and OFDMA with M = 256 system subcarriers, N=64 subcarriers per users, and a = 0.5 roll factor; (a) QPSK; (b) 16-QAMSource:H.G. Myung, J.Lim, D.J. Goodman “SC-FDMA for Uplink Wireless Transmission”,IEEE VEHICULAR TECHNOLOGY MAGAZINE, SEPTEMBER 2006
SC-FDMA parameterization (FDD and TDD)LTE FDD•Same as in downlinkTD-LTE•Usage of UL depends on the selected UL-DL configuration (1 to 8), eachconfiguration offers a different number of subframes (1ms) for uplinktransmission,•Parameterization for those subframes, means number of SC-FDMA symbolssame as for FDD and depending on CP, 82
Improved UL Performance SC-FDMA compared to ordinary OFDMSingle-carrier transmission in uplink enables low PAPR that gives more 4 dB better link budget and reduced power consumption compared to OFDM 83
LTE Uplink SC-FDMA Physical Layer Parameters 84
Physical Channel Processing• Scrambling: Scramble binary information• Modulation Mapper: Maps groups of 2, 4, or 6 bits onto QPSK, 16QAM, 64QAM symbol constellation points• Transform Precoder: Slices the input data vector into a set of symbol vectors and perform DFT transformation.• Resource Element Mapper: Maps the complex constellation points into the allocated virtual resource blocks and performs translation into physical resource blocks.• SC-FDMA Signal Generation: Performs the IFFT processing to generate final time domain for transmission. 85
SC-FDMA and OFDMA Signal Chain Have a High Degree of Functional Commonality Cyclic Single Carrier S/P Symbol M-Point Subcarrier N-Point Bit Prefix & RFE Constellation Convert Block DFT Mapping IDFT Stream Pulse Mapping Shaping Channel Const. Freq Cyclic Bit SC S/P Symbol M-Point N-Point De-map Domain Prefix RFEStream Detector Convert Block IDFT DFT Equalizer Removal Functions Common to OFDMA and SC-FDMA SC-FDMA Only 86
Session 4: Network and Protocol •Network architecture •Protocol Stack – User plane •Protocol Stack – Control plane •Mapping between logical and transport channel •LTE UE Categories
LTE Network Architecture UMTS 3G: UTRAN EPC GGSN MME MME S-GW / P-GW P- S-GW / P-GW P- SGSN RNC RNC eNB eNB eNB eNB NB NB NB NB E-UTRANUMTS : Universal Mobile Telecommunications System EPC ; Evolved Packet CoreUTRAN : Universal Terrestrial Radio Access Network MME : Mobility Management EntityGGSN : Gateway GPRS Support Node S-GC : Serving GatewayGPRS: General Packet Radio Service P-GW : PDN GatewaySGSN : Serving GPRS Support Node PDN : Packet Data NetworkRNC: Radio Network Controller eNB : E-UTRAN Node B / Evolved Node BNB: Node B E-UTRAN ; Evolved-UTRAN
Simplified LTE network elements and interfaces 3GPP TS 36.300 : Overall Architecture EPC: Evolved Packet Core Radio Side: LTE – Long Term Evolution EPC • Improvements in spectral efficiency, user MME throughput, latency. MME • Simplification of the radio network S-GW / P-GW P- S-GW / P-GW P- • Efficient support of packet services • Main Components: • MME = Manages mobility, UE identity, and security parameters. • S-GW = Node that terminates the interface S1 towards E-UTRAN. • P-GW = Node that terminates the interface towards PDNeNB X2 eNB E-UTRAN : Evolved-UTRAN eNB eNB Network Side : SAE – System Architecture Evolution E-UTRAN • Improvement in latency, capacity, throughput • Simplification of the core network • Optimization for IP traffic services • Simplified support and handover to non-3GPP access technologies • Main Components: • eNB = All radio interface-related functions
EPS Network Elements S6a Gx Rx S1-MME MME Operator’s LTE-Uu S1-U S5 / S8 SGi IP Services S-GW P-GW (e.g. IMS, PSS, eNB etc,) UE E-UTRAN EPC• UE, E-UTRAN and EPC together represent the Internet Protocol (IP) Connectivity Layer.• This part of the system is also called the Evolved Packet System (EPS).• The main function of this layer is to provide IP based connectivity, and it is highly optimized for that purpose only.• All services will be offered on top of IP, and circuit switched nodes and interfaces seen in earlier 3GPP architectures are not present in E-UTRAN and EPC at all.• IP technologies are also dominant in the transport, where everything is designed to be operated on top of IP transport.
System architecture for E-UTRAN only network
Services • The IP Multimedia Sub-System (IMS) is a good example of service machinery that can be used in the Services Connectivity Layer to provide services on top of the IP connectivity provided by the lower layers. • For example, to support the voice service, IMS can provide Voice over IP (VoIP) and interconnectivity to legacy circuit switched networks PSTN and ISDN through Media Gateways it controls.
EPC • Functionally the EPC is equivalent to the packet switched domain of the existing 3GPP networks. • Significant changes in the arrangement of functions and most nodes and the architecture in this part should be considered to be completely new. • SAE GW represents the combination of the two gateways, Serving Gateway (S-GW) and Packet Data Network Gateway (P-GW) defined for the UP handling in EPC. • Implementing them together as the SAE GW represents one possible deployment scenario, but the standards define the interface between them, and all operations have also been specified for when they are separate. • The Basic System Architecture Configuration and its functionality are documented in 3GPP TS 23.401. • We will learn the operation when the S5/S8One of the big architectural changes in the interface uses the GTP protocol. However, whencore network area is that the EPC does the S5/S8 interface uses PMIP, the functionality fornot contain a circuit switched domain, and these interfaces is slightly different, and the Gxcno direct connectivity to traditional circuit interface also is needed between the Policy andswitched networks such as ISDN or PSTN Charging Resource Function (PCRF) and S-GW.is needed in this layer.
E-UTRAN • The development in E-UTRAN is concentrated on one node, the evolved Node B (eNodeB). • All radio functionality is collapsed there, i.e. the eNodeB is the termination point for all radio related protocols. • As a network, E-UTRAN is simply a mesh of eNodeBs connected to neighbouring eNodeBs with the X2 interface.
User Equipment • UE is the device that the end user uses for communication. • Typically it is a hand held device such as a smart phone or a data card such as those used currently in 2G and 3G, or it could be embedded, e.g. to a laptop. • UE also contains the Universal Subscriber Identity Module (USIM) that is a separate module from the rest of the UE, which is often called the Terminal Equipment (TE). • USIM is an application placed into a removable smart card called the Universal Integrated Circuit Card (UICC). • USIM is used to identify and authenticate theFunctionally the UE is a platform for communication user and to derive security keys for protecting applications, which signal with the network for setting the radio interface transmission. up, maintaining and removing the communication links • Maybe most importantly, the UE provides the the end user needs.This includes mobility management functions such as user interface to the end user so that handovers and reporting the terminals location, and in applications such as a VoIP client can be used to these the UE performs as instructed by the network. set up a voice call.
User Equipment Capabilities 1G Analog 2G Digital 3G Packets 4G True Broadband• Support Spectrum flexibility – Flexible bandwidth 1.4 MHz 20 MHz – New and existing bands
Downlink physical layer parameter values set by the field UE-Category UE Category Maximum number of Maximum number of Total number of Maximum number of DL-SCH transport block bits of a DL-SCH soft channel bits supported layers for bits received within a transport block spatial multiplexing TTI (Note) received within a TTI in DLCategory 1 10296 10296 250368 1Category 2 51024 51024 1237248 2Category 3 102048 75376 1237248 2Category 4 150752 75376 1827072 2Category 5 299552 149776 3667200 4Category 6 301504 149776 (4 layers) 3654144 2 or 4 75376 (2 layers)Category 7 301504 149776 (4 layers) 3654144 2 or 4 75376 (2 layers)Category 8 2998560 299856 35982720 8NOTE: In carrier aggregation operation, the DL-SCH processing capability can be shared by the UE with that of MCH received from a serving cell. If the total eNB scheduling for DL-SCH and an MCH in one serving cell at a given TTI is larger than the defined processing capability, the prioritization between DL-SCH and MCH is left up to UE implementation.TTI = Transmission Time IntervalMIMO = Multiple Input Multiple Output 3GPP TS 36.306 V11.1.0 (2012-09)UL-SCH = Uplink Shared Channel 3rd Generation Partnership Project;DL-SCH = Downlink Shared Channel Technical Specification Group Radio Access Network;UE = User Equipment Evolved Universal Terrestrial Radio Access (E-UTRA);TTI = Transmission Time Interval User Equipment (UE) radio access capabilities
Transmission Time Interval• Transmission Time Interval: Transmission Time Interval is defined as the inter-arrival time of Transport Block Sets, i.e. the time it shall take to transmit a Transport Block Set.• Transport Block Set: Transport Block Set is defined as a set of Transport Blocks that is exchanged between L1 and MAC at the same time instance using the same transport channel. An equivalent term for Transport Block Set is “MAC PDU Set”.• Transport Block: Transport Block is defined as the basic data unit exchanged between L1 and MAC. An equivalent term for Transport Block is “MAC PDU”. 3GPP TR 21.905 V11.2.0 (2012-09) 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Vocabulary for 3GPP Specifications (Release 11)
Uplink physical layer parameter values set by the field UE-Category UE Category Maximum number of UL- Maximum number of Support for 64QAM SCH transport block bits bits of an UL-SCH in UL transmitted within a TTI transport block transmitted within a TTICategory 1 5160 5160 NoCategory 2 25456 25456 NoCategory 3 51024 51024 NoCategory 4 51024 51024 NoCategory 5 75376 75376 YesCategory 6 51024 51024 NoCategory 7 102048 51024 NoCategory 8 1497760 149776 Yes 3GPP TS 36.306 V11.1.0 (2012-09) 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio access capabilities
Functional split between E-UTRAN and Evolved Packet Core eNB E-UTRAN aGW eNodeB • Paging origination • All Radio-related issues • LTE_IDLE mode management • Decentralized mobility • Ciphering of the user plane management • Header Compression (ROHC) • MAC and RRM • Simplified RRC S1 aGW InternetThe E-UTRAN consists of eNBs, providing: RRM : Radio Resource Management• The E-UTRA U-plane (RLC/MAC/PHY) and RRC: Radio Resource Control• The C-plane (RRC) protocol terminations MAC : Medium Access Control ROHC: RObust Header Compression towards the UE. RLC: Radio Link Control• The eNBs interface to the aGW via the S1 PHY: Physical Layer
Protocol eNB E-UTRAN Inter Cell RRM MME RB Cont. NAS Security Connection Mobility Cont. EPC Idle State Mobility Handling Radio Admission Cont. eNB Measurement EPS Bearer Cont. Configuration & Provision Dynamic Resource Allocation (Scheduler) SAE GW RRC S-GW P-GW PDCP UE IP Address Mobile Anchoring RLC Allocation S1 MAC Packet Filtering PHY InternetRRM : Radio Resource Management NAS : Non Access StratumRB : Radio Bearer EPS : Evolved Packet SystemRRC: Radio Resource Control UE : User EquipmentPDCP : Packet Data Convergence Protocol IP : Internet ProtocolRLC : Radio Link ControlMAC : Medium Access ControlPHY : Physical Layer
LTE Control PlaneUE eNB aGW Non Access Stratum (NAS) is aNAS NAS functional layer in UMTS protocol stack between CoreRRC RRC S1 Network and User EquipmentPDCP PDCP (UE). The layer supports signaling andRLC RLC traffic between two elements.MAC MACPHY PHY LTE User Plane Packet Data Convergence Protocol (PDCP) is a one of the layers of Radio Traffic Stack in UMTSUE eNB aGW and perform as IP header IP IP compression and decompression, transfer ofPDCP PDCP S1 user data and maintenance ofRLC RLC sequence numbers for Radio Bearers which are configuredMAC MAC for lossless Serving RadioPHY PHY Networks Subsystems (SRNS) relocation.
LTE Protocol Stacks (UE and eNB) RRC: Radio Resource Control Control-Plane User-Plane PDCP : Packet Data Convergence Protocol RLC : Radio Link ControlL3 RRC MAC : Medium Access Control PHY : Physical Layer Radio Bearers PDCPL2 RLC Logical Channels MAC Transport ChannelsL1 PHY: Physical Channels Physical Signals
Control plane protocol stack in EPSThe topmost layer in the CP is the Non-Access Stratum (NAS), which consists of two separate protocols that are carried on direct signaling transport between the UE and the MME.The content of the NAS layer protocols is not visible to the eNodeB, and the eNodeB is not involved in these transactions by any other means, besides transporting the messages, and providing some additional transport layer indications along with the messages in some cases.
NAS layer protocolsThe NAS layer protocols are:• EPS Mobility Management (EMM): The EMM protocol is responsible for handling the UE mobility within the system. It includes functions for attaching to and detaching from the network, and performing location updating in between. This is called Tracking Area Updating (TAU), and it happens in idle mode. Note that the handovers in connected mode are handled by the lower layer protocols, but the EMM layer does include functions for re-activating the UE from idle mode. The UE initiated case is called Service Request, while Paging represents the network initiated case. Authentication and protecting the UE identity, i.e. allocating the temporary identity GUTI to the UE are also part of the EMM layer, as well as the control of NAS layer security functions, encryption and integrity protection.• EPS Session Management (ESM): This protocol may be used to handle the bearer management between the UE and MME, and it is used in addition for E-UTRAN bearer management procedures. Note that the intention is not to use the ESM procedures if the bearer contexts are already available in the network and E- UTRAN procedures can be run immediately. This would be the case, for example, when the UE has already signaled with an operator affiliated. Application Function in the network, and the relevant information has been made available through the PCRF.
User plane protocol stack in EPSThe UP includes the layers below the end user IP, i.e. these protocols form the Layer 2 used for carrying the end user IP packets.The protocol structure is very similar to the CP.This highlights the fact that the whole system is designed for generic packet data transport, and both CP signaling and UP data are ultimately packet data. Only the volumes are different.
Summary of interfaces and protocols in Basic System Architecture configuration