LTE - Long Term Evolution

Arief Hamdani Gunawan 21 November 2009

Main Topics
Introduction
Network Architecture
System Architecture Evolution
Channels
Downlink Transmission Scheme
Uplink Transmission Scheme
MIMO
LTE-Advanced
Conclusion

LTE market situation based on HSPA success story
HSPA growth is based on the uptake of mobile data services worldwide.
More than 250 networks worldwide have already commercially launched HSPA.
Mobile data traffic is growing exponentially, caused by mobile Internet offerings and improved user experience with new device types.
LTE is accepted worldwide as the long term evolution perspective for today’s 2G and 3G networks based on WCDMA/HSPA, GSM/EDGE, TD-SCDMA, and CDMA2000 technologies.
Sources: www.gsacom.com, R&S

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.

Introduction to LTE
3GPP Long Term Evolution - the next generation of wireless cellular technology beyond 3G
Initiative taken by the 3rd Generation Partnership Project in 2004
Introduced in Release 8 of 3GPP
Mobile systems likely to be deployed by 2010

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 CA pital and OP erational EX penditures (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)”.

3G deployment in the world China Mobile NTT DoCoMo （ 2010 ） KDDI Verizon （ 2009 ） AT&T W （ 2010 ） Vodafone （ 2011 ） T-Mobile （ 2010 ） China Telecom HSPA+ DL>40MBps; UL>10Mbps TD-HSDPA 2.8~8.4Mbps TD-HSUPA 2.2~6.6Mbps WCDMA 384Kbps HSDPA 1.8/3.6Mbps HSDPA 7.2Mbps HSUPA 1.4~5.8Mbps LTE TDD DL:100Mbps UL:50Mbps TD-HSPA+ DL:>25.2Mbps UL:>19.2Mbps EV-DO Rel. 0 DL: 2.4Mbps UL:153.6kbps cdma2000 1x 153.6kbps D0 Rel. A DL: 3.1Mbps UL: 1.8Mbps Do Rev B (Multi Carrier DO) DL ： 46.5Mbps UL: 27Mbps LTE FDD DL:100Mbps UL:50Mbps LTE TDD1 LTE TDD2

Trend of B3G ITU IMT-Advanced(4G) UMB ＋ 100Mbps-1Gbps 100Mbps~ 1Gbps LTE+ FDD/TDD DL:100Mbps UL:50Mbps LTE-FDD WIMAX 3GPP 3GPP2 B3G EV-DO Rel. 0 DL: 2.4Mbps UL:153.6kbps cdma2000 1x 153.6kbps D0 Rel. A DL: 3.1Mbps UL: 1.8Mbps Do Rev B （多载波 DO ） DL ： 46.5Mbps UL: 27Mbps UMB DL: 100Mbps UL: 50Mbps TD-HSPA+ DL:>25.2Mbps UL:>19.2Mbps TD-HSDPA 2.8~8.4Mbps TD-HSUPA 2.2~6.6Mbps HSPA+ DL>40MBps; UL>10Mbps WCDMA 384Kbps HSDPA 1.8/3.6Mbps HSDPA 7.2Mbps HSUPA 1.4~5.8Mbps GREAN ~600kbps GPRS/EDGE ~ 200kbps LTE-TDD DL:100Mbps UL:50Mbps 16m 100Mbps~1Gbps Mobile WiMAX Wave1 15Mbps Mobile WiMAX Wave2 30Mbps

4G Technologies Mobile WiMAX 3GPP IP E2E Network IP E2E Network CKT Switched Network OFDMA - Based CDMA - Based IMT- Advanced 2008 2009 2010 2011 2012

Evolution of UMTS FDD and TDD driven by data rate and latency requirements

LTE Network Architecture

LTE will Ensure the Success of Mobile Internet

LTE Offers 10-30x Improvement on cost/performance vs. existing technologies

LTE – The Right Solution for Mobile Internet

What’s Happening in Mobile Internet World -- Device Providers --

LTE Key Parameters

Modulation
QPSK, 16 QAM and 64 QAM used for the payload channels (spectrally efficient)
BPSK and QPSK used for the control channels (Reliability and coverage)
Adaptive modulation and coding

Requirements to be met by LTE Fast, Efficient, Cheap, Simple
Peak Data Rates
Spectrum efficiency
Reduced Latency
Mobility
Spectrum flexibility
Coverage
Low complexity and cost
Interoperability
Simple packet-oriented E-UTRAN architecture

Simplified LTE network elements and interfaces 3GPP TS 36.300 Figure 4: Overall Architecture eNB = E-UTRAN Node B All radio interface-related functions MME = Mobile Management entity – Manages mobility, UE identity, and security parameters. S-GW = Serving Gateway – Node that terminates the interface towards E-UTRAN. P-GW = PDN (Packet Data Network) Gateway – Node that terminates the interface towards PDN.

LTE Network Architecture
Simple Architecture
Flat IP-Based Architecture
Reduction in latency and cost
Split between EPC and E-UTRAN
Compatibility with 3GPP and non-3GPP technologies
eNB-radio interface-related functions
MME-manages mobility, UE identity and security parameters
S-GW-node that terminates the interface towards E-UTRAN
EPC = Evolved Packet Core
E-UTRAN = Evolved Universal Radio Access Network
MME = Mobile Management entity
S-GW = Serving Gateway
SAE = System Architecture Evolution
eNB = E-UTRAN Node B

PDCP = Packet Data Convergence Protocol RRC = Radio Resource Control RLC = Radio Link Control

Protocol

System Architecture Evolution
SAE is a study within 3GPP targeting at the evolution of the overall system architecture.
Objective is “to develop a framework for an evolution or migration of the 3GPP system to a higher-data-rate, lower-latency, packet optimized system that supports multiple radio access technologies.
The focus of this work is on the PS domain with the assumption that voice services are supported in this domain". This study includes the vision of an all-IP network.

Why LTE/SAE?
Packet Switched data is becoming more and more dominant
VoIP is the most efficient method to transfer voice data
 Need for PS optimised system
Amount of data is continuously growing
 Need for higher data rates at lower cost
Users demand better quality to accept new services
High quality needs to be quaranteed
Alternative solution for non-3GPP technologies (WiMAX) needed
LTE will enhance the system to satisfy these requirements.

LTE Overview
3GPP R8 solution for the next 10 years
Peaks rates: DL 100Mbps with OFDMA, UL 50Mbps with SC-FDMA
Latency for Control-plane < 100ms, for User-plane < 5ms
Optimised for packet switched domain, supporting VoIP
Scaleable RF bandwidth between 1.25MHz to 20MHz
200 users per cell in active state
Supports MBMS multimedia services
Uses MIMO multiple antenna technology
Optimised for 0-15km/h mobile speed and support for up-to 120-350 km/h
No soft handover, Intra-RAT handovers with UTRAN
Simpler E-UTRAN architecture: no RNC, no CS domain, no DCH

LTE technical objectives and architecture
User throughput [/MHz] :
Downlink: 3 to 4 times Release 6 HSDPA
Uplink: 2 to 3 times Release 6 Enhanced Uplink
Downlink Capacity : Peak data rate of 100 Mbps in 20 MHz maximum bandwidth
Uplink capacity : Peak data rate of 50 Mbps in 20 MHz maximum bandwidth
Latency : Transition time less than 5 ms in ideal conditions (user plane), 100 ms control plane (fast connection setup)

Mobility : Optimised for low speed but supporting 120 km/h
Most data users are less mobile!
Simplified architecture : Simpler E-UTRAN architecture: no RNC, no CS domain, no DCH
Scalable bandwidth : 1.25MHz to 20MHz: Deployment possible in GSM bands.

LTE radio interface
New radio interface modulation: SC-FDMA UL and OFDMA DL
Frequency division, TTI 1 ms
Scalable bandwidth 1.25-20MHz
TDD and FDD modes
UL/DL in either in same or in another frequncy
OFDMA has multiple orthogonal subcarries that can be shared between users
quickly adjustable bandwith per user
SC-FDMA is technically similar to OFDMA but is better suited for uplink from hand-held devices
Single carrier, time space multiplexing
Tx consumes less power
From Ericsson, H. Djuphammar

LTE/SAE Keywords
aGW Access Gateway
eNB Evolved NodeB
EPC Evolved Packet Core
E-UTRAN Evolved UTRAN
IASA Inter-Access System Anchor
LTE Long Term Evolution of UTRAN
MME Mobility Management Entity
OFDMA Ortogonal Frequency Division Multiple Access
SC-FDMA Single Carrier Frequency Division Multiple Access
SAE System Architecture Evolution
UPE User Plane Entity

3GPP TR 23.401 / 25.813
PLMN –Public Land Mobile Network
EPS –Evolved Packet System
MME –Mobility Management Entity
eNB–E-UTRAN Node B
TAI -Tracking Area ID
E-UTRAN –Evolved Universal Radio Access Network
C-RNTI –Cell Radio Network Temporary Identifier
RA-RNTI –Random Access RNTI
UE –User Equipment
IMEI –International Mobile Equipment Identity
IMSI –International Mobile Subscriber Identity
S-TMSI –SAE Temporary Mobile Subscriber Identity
Network Entities: MME ID eNB ID TAI Network: PLMN EPS ID EUTRAN: E-UTRAN C-RNTI RA-RNTI UE: IMEI IMSI S-TMSI LTE/SAE Network Identifiers

System architecture evolution

RAN interfaces
X2 interface between eNBs for handovers
Handover in 10 ms
No soft handovers
Interfaces using IP over E1/T1/ATM/Ethernet /…
Load sharing in S1
S1 divided to S1-U (to UPE) and S1-C (to CPE)
Single node failure has limited effects
S1 S8 X2 X2 eNB aGW eNB aGW eNB

SAE architecture [3GPP TS 23.401] Evolved Packet Core S11 S2 S3 S4 S7 S6 SGi S1 Gb Iu Rx+ X1 X1 X2 Evolved RAN aGW S5 GERAN UTRAN GPRS Core MME UPE SAE GW PCRF Operator IP services (including IMS, PSS, ...) Non-3GPP IP Access eNB eNB PDN SAE GW HSS

SAE architechture [3GPP TS 23.401] S1 TBD S8 X2 Operator IP service, including IMS S11 S11 S5 SGi Evolved RAN IASA aGW = MME/UPE S6a S7 TBD eNB TBD eNB aGW eNB SAE GW PDN SAE GW HSS PCRF aGW

Functions of eNB
Terminates RRC, RLC and MAC protocols and takes care of Radio Resource Management functions
Controls radio bearers
Controls radio admissions
Controls mobility connections
Allocates radio resources dynamically (scheduling)
Receives measurement reports from UE
Selects MME at UE attachment
Schedules and transmits paging messages coming from MME
Schedules and transmits broadcast information coming from MME & O&M
Decides measurement report configuration for mobility and scheduling
Does IP header compression and encryption of user data streams

Functions of aGW
Takes care of Mobility Management Entity (MME) functions
Manages and stores UE context
Generates temporary identities and allocates them to UEs
Checks authorization
Distributes paging messages to eNBs
Takes care of security protocol
Controls idle state mobility
Control SAE bearers
Ciphers & integrity protects NAS signaling

Takes care of User Plane Entity (UPE) functions
Terminates for idle state UEs the downlink data path and triggers/initiates paging when downlink data arrive for the UE.
Manages and stores UE contexts, e.g. parameters of the IP bearer service or network internal routing information.
Switches user plane for UE mobility
Terminates user plane packets for paging reasons

Functions S1

LTE Control Plane
aGW UE eNB S1 RRC RLC MAC PHY PDCP RRC RLC MAC PHY PDCP NAS NAS

LTE User Plane
aGW UE eNB S1 RLC MAC PHY PDCP RLC MAC PHY PDCP IP IP

GTP-U tunneling SAE GW UPE eNB Server UE L1 L2 X1 S1 S11 SGi S5 PDN SAE GW Header compression & encryption Radio L1 MAC PDCP IPv6/v4 u Application TCP/UDP RLC L1 L2 IP UDP GTP-U L2 L1 IP UDP GTP-U L2 L1 IP UDP GTP-U L2 L1 IPv6/v4 TCP/UDP Application L1 L2 IP UDP GTP-U L2 L1 IP UDP GTP-U L2 L1 IP UDP GTP-U L2 L1 Radio L1 MAC RLC PDCP ENC

Non-3GPP access tunneling PDN SAE GW HA AP Server UE IP L2 L1 IPv6/v4 TCP/UDP Application L1 L2 WLAN S2 SGi L2 L1 IP MIP IPv4/6 IP UDP IP MIP IPv4/6 UDP IP L2 L1 IP L2 L1 L1 L2 L1 L2

LTE Physical Layer
Enables exchange of data & control info between eNB and UE and also transport of data to and from higher layers
Functions performed include error detection, FEC, MIMO antenna processing, synchronization, etc.
It consists of Physical Signals and Physical Channels
Physical Signals are used for system synchronization, cell identification and channel estimation.
Physical Channels for transporting control, scheduling and user payload from the higher layers
OFDMA in the DL, SC-FDMA in the UL
LTE supports FDD and TDD modes of operation

Channel Mapping

LTE Physical Signals

LTE Physical Channels

LTE Transport Channels
Physical layer transport channels offer information transfer to medium access control (MAC) and higher layers.
DL
Broadcast Channel (BCH)
Downlink Shared Channel (DL-SCH)
Paging Channel (PCH)
Multicast Channel (MCH)
UL
Uplink Shared Channel (UL-SCH)
Random Access Channel (RACH)

LTE Logical Channels
Logical channels are offered by the MAC layer.
Control Channels: Control-plane information
Broadcast Control Channel (BCCH)
Paging Control Channel (PCCH)
Common Control Channel (CCCH)
Multicast Control Channel (MCCH)
Dedicated Control Channel (DCCH)
Traffic Channels: User-plane information
Dedicated Traffic Channel (DTCH)
Multicast Traffic Channel (MTCH)

LTE Frame Structure (Downlink)
LTE Frame Structure Type I (FDD)
LTE Frame Structure Type II (TDD)

FDD (left) and TDD (right) frequency bands defined in the 3GPP (May 2009)

Downlink Transmission Scheme
The downlink transmission scheme for E-UTRA FDD and TDD modes is based on conventional OFDM. In an OFDM system, the available spectrum is divided into multiple carriers, called sub-carriers, which are orthogonal to each other. Each of these sub-carriers is independently modulated by a low rate data stream.
OFDM is used as well in WLAN, WiMAX and broadcast technologies like DVB. OFDM has several benefits including its robustness against multipath fading and its efficient receiver architecture.

OFDM
Single Carrier Transmission (e.g. WCDMA)
Orthogonal Frequency Division Multiplexing

OFDM signal generation chain
OFDM signal generation is based on Inverse Fast Fourier Transform (IFFT) operation on transmitter side:
On receiver side, an FFT operation will be used.

Modulation
QPSK, 16 QAM and 64 QAM used for the payload channels (spectrally efficient)
BPSK and QPSK used for the control channels (Reliability and coverage)
Adaptive modulation and coding

Difference between OFDM and OFDMA
OFDM allocates users in time domain only
OFDMA allocates users in time and frequency domain

LTE downlink conventional OFDMA Frequency-Time Representation of an OFDM Signal
LTE provides QPSK, 16QAM, 64QAM as downlink modulation schemes
Cyclic prefix is used as guard interval, different configurations possible:
Normal cyclic prefix with 5.2 Os (first symbol) / 4.7 Os (other symbols)
Extended cyclic prefix with 16.7 Os
15 kHz subcarrier spacing
Scalable bandwidth

Frequency and Time Domain Representation
Frequency Time

OFDMA time-frequency multiplexing

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

Generic frame structure in E-UTRA downlink
For the generic frame structure frame structure, the 10 ms radio frame is divided into 20 equally sized slots of 0.5 ms.
A sub-frame consists of two consecutive slots, so one radio frame contains 10 sub-frames.

Downlink Resource Grid
The available downlink bandwidth consists of N DL BW sub-carriers with a spacing of Δ f = 15 kHz. In case of multi cell MBMS transmission,
a sub-carrier spacing of Δ f = 7.5 kHz is also possible.
N DL BW can vary in order to allow for scalable bandwidth operation up to 20 MHz. Initially, the bandwidths for LTE were explicitly defined within layer 1 specifications.
Later on a bandwidth agnostic layer 1 was introduced, with N DL BW for the different bandwidths to be specified by 3GPP RAN4 to meet performance requirements, e.g. for out-of-band emission requirements and regulatory emission limits

The LTE downlink physical resource based on OFDM

Parameters for downlink generic frame structure

Downlink Data Transmission
The user data is carried on the Physical Downlink Shared Channel ( PDSCH ).
Downlink control signaling on the Physical Downlink Control Channel ( PDCCH ) is used to convey the scheduling decisions to individual UEs.
The PDCCH is located in the first OFDM symbols of a slot.

Downlink Reference Signal Structure and Cell Search
The downlink reference signal structure is important for cell search, channel estimation and neighbor cell monitoring.
The reference signal sequence carries the cell identity.

Downlink reference signal structure

P-SCH and S-SCH
Besides the reference symbols, synchronization signals are therefore needed during cell search.
E-UTRA uses a hierarchical cell search scheme similar to WCDMA.
This means that the synchronization acquisition and the cell group identifier are obtained from different SCH signals.
Thus, a primary synchronization signal (P-SCH) and a secondary synchronization signal (S-SCH) are defined with a pre-defined structure.
They are transmitted on the 72 centre sub-carriers (around DC sub-carrier) within the same predefined slots (twice per 10 ms) on different resource elements

P-SCH and S-SCH structure

CCPCH
As additional help during cell search, a Common Control Physical Channel ( CCPCH) is available which carries BCH type of information, e.g. system bandwidth.
It is transmitted at pre-defined time instants on the 72 subcarriers centered around DC sub-carrier.

Downlink Physical Layer Procedures
Cell search and synchronization:
Scheduling: Scheduling is done in the base station (eNodeB). The downlink control channel PDCCH informs the users about their allocated time/frequency resources and the transmission formats to use. The scheduler evaluates different types of information, e.g. Quality of Service parameters, measurements from the UE, UE capabilities, buffer status.
Link Adaptation: Link adaptation is already known from HSDPA as Adaptive Modulation and Coding. Also in E-UTRA, modulation and coding for the shared data channel is not fix, but it is adapted according to radio link quality. For this purpose, the UE regularly reports Channel Quality Indications (CQI) to the eNodeB.
Hybrid ARQ (Automatic Repeat Request): Downlink Hybrid ARQ is also known from HSDPA. It is a retransmission protocol. The UE can request retransmissions of incorrectly received data packets.

DL Physical Channel Processing

LTE frame structure type 1 (FDD), downlink

LTE frame structure type 2 (TDD)

Uplink Transmission Scheme
During the study item phase of LTE, alternatives for the optimum uplink transmission scheme were investigated.
While OFDMA is seen optimum to fulfil the LTE requirements in downlink, OFDMA properties are less favorable for the uplink. This is mainly due to weaker peak-to-average power ratio (PAPR) properties of an OFDMA signal, resulting in worse uplink coverage.

Single-Carrier Frequency Division Multiple Access (SC-FDMA)
Thus, the LTE uplink transmission scheme for FDD and TDD mode is based on SC-FDMA (Single Carrier Frequency Division Multiple Access) with cyclic prefix.
SC-FDMA signals have better PAPR properties compared to an OFDMA signal.
This was one of the main reasons for selecting SCFDMA as LTE uplink access scheme.
The PAPR characteristics are important for cost-effective design of UE power amplifiers.
Still, SC-FDMA signal processing has some similarities with OFDMA signal processing, so parameterization of downlink and uplink can be harmonized.

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.

OFDMA and SC-FDMA

Why does SC-FDMA have a low PAPR?
OFDMA
Parallel Transmission
Multi carrier structure
Increase in M =>
high PAPR
SC-FDMA
Serial Transmission
Each symbol
represented by a
wide signal – DFT spreads
symbols over all subcarriers
PAPR not affected by
increase in M
Both occupy the same bandwidth with same symbol durations

SC-FDMA in comparison with OFDMA and DS-CDMA/FDE

SC-FDMA signal generation Localized vs. distributed FDMA

Uplink Slot Structure

Parameters for uplink generic structure

Uplink Data Transmission
In uplink, data is allocated in multiples of one resource block. Uplink resource block size in the frequency domain is 12 sub-carriers, i.e. the same as in downlink.
However, not all integer multiples are allowed in order to simplify the DFT design in uplink signal processing.
Only factors 2,3, and 5 are allowed.
The uplink transmission time interval is 1 ms (same as downlink).

PUSCH and PUCCH
User data is carried on the Physical Uplink Shared Channel ( PUSCH ) that is determined by the transmission bandwidth NTx and the frequency hopping pattern k0.
The Physical Uplink Control Channel ( PUCCH ) carries uplink control information, e.g. CQI reports and ACK/NACK information related to data packets received in the downlink. The PUCCH is transmitted on a reserved frequency region in the uplink.

Uplink Reference Signal Structure
Uplink reference signals are used for two different purposes: on the one hand, they are used for channel estimation in the eNodeB receiver in order to demodulate control and data channels.
On the other hand, the reference signals provide channel quality information as a basis for scheduling decisions in the base station. The latter purpose is also called channel sounding.
The uplink reference signals are based on CAZAC (Constant Amplitude Zero Auto-Correlation) sequences.

UL Physical Channel Processing

Cell Search
Cell search: Mobile terminal or user equipment (UE) acquires time and frequency synchronization with a cell and detects the cell ID of that cell.
Based on BCH (Broadcast Channel) signal and hierarchical SCH (Synchronization Channel) signals.
P-SCH (Primary-SCH) and S-SCH (Secondary-SCH) are transmitted twice per radio frame (10 ms) for FDD.
Cell search procedure
1. 5 ms timing identified using P-SCH.
2. Radio timing and group ID found from S-SCH.
3. Full cell ID found from DL RS.
4. Decode BCH.

Spatial Multiplexing Spatial multiplexing allows to transmit different streams of data simultaneously on the same downlink resource block(s). These data streams can belong to one single user (single user MIMO / SU-MIMO) or to different users (multi user MIMO / MU-MIMO). While SU-MIMO increases the data rate of one user, MU-MIMO allows to increase the overall capacity. Spatial multiplexing is only possible if the mobile radio channel allows it.

LTE MIMO concept

Multiple Antenna Schemes in LTE
In DL : Tx diversity, Rx diversity, Spatial multiplexing (2x2,4x2 configurations – SU-MIMO and MU-MIMO) supported
In UL : Only 1 Transmitter (antenna selection Tx diversity ), MU-MIMO possible, Rx diversity with 2 or 4 antennas at eNB supported

LTE cooperative MIMO

Collaborative/Network MIMO overview Coordinate transmission and reception of signals among multiple bases. Reduces intercell interference and improves cell-edge performance and overall throughput. Collaborative MIMO : share user data and long-term noncoherent channel information. Coherent network MIMO : share user data and short-term coherent channel information.

Multi-Mode Adaptive MIMO for DL/UL
Use adaptive MIMO to accommodate demand of higher data rate and wider coverage in next generation broadband wireless access
SU MIMO for peak user data rate improvement
MU MIMO for average data rate enhancement
Collaborative/Network MIMO for cell edge user data rate boost
A uniform MIMO platform SU-MIMO MU-MIMO Collaborative/ Network MIMO adaptive selection MAC layer Cross-layer design

Key technologies in Multi-mode Adaptive MIMO Cellular system Collaborative/Network MIMO MU-MIMO SU-MIMO
SU-MIMO enhancement
Closed-loop MIMO
Iterative MIMO receiver
MU-MIMO optimization
MU precoding algorithm
Trade-off design of scheduler between complexity and performance
Collaborative/Network MIMO/Beam Coordination
Implementation of multi-BS collaboration with channel information
Multi-dimension adaptation
Adaptation strategy
Multi-variable channel measurement
Low-rate feedback mechanism
Multicast Anchor Serving eNB/ per User Data + Sync Protocol for DL (Extension of eMBMS protocol); Data + Channel Estimates for UL eNBs have to be synchronized !!! MIMO channel

LTE doesn’t fulfill the requirements of IMT-Advanced
3GPP has also started work on LTE-Advanced, an evolution of LTE, as a proposal to ITU-R for the development of IMT Advanced.
LTE Advanced is envisioned to be the “first true 4G technology”.

Requirements of LTE Advanced
Peak data rates – 1Gbps in DL and 500 Mbps in UL
Cell edge user data rates twice as high and average user throughput thrice as high as in LTE
Peak spectrum efficiency DL: 30 bps/Hz, UL: 15 bps/Hz
Operate in flexible spectrum allocations up to 100 MHz and support spectrum aggregation (as BW in DL >>20 MHz)
An LTE-Advanced capable network must appear as a LTE network for the LTE UEs

Technological proposals for LTE Advanced
Larger BW can be used for high date rates and more coverage at cell edges
Advanced repeater structures
Relaying for adaptive coding based on link quality
Carrier aggregation and Spectrum aggregation

Conclusion
3GPP Long Term Evolution has a large amount of potential to become the technology of the future whose success will definitely guarantee that 3GPP has a significant edge over all its competitors.
With LTE–Advanced also adopting SC-FDMA as the uplink technology, SC-FDMA seems to be an important future technology and it is expected that the future would see a lot of research activity in this field.
LTE and LTE Advanced together seem to be very promising in fulfilling all the requirements set forth by ITU for IMT Advanced

References
http://www.3gpp.com/article/lte
http://www.3gpp.com/article/lte-advanced.
http://en.wikipedia.org/wiki/LTE_Advanced
UTRA-UTRAN Long Term Evolution (LTE) and 3GPP System Architecture Evolution (SAE) - Technical paper from http://www.3gpp.com/article/lte
Overview of the 3GPP Long Term Evolution Physical Layer – White paper by Jim Zyren, freescale semiconductor, Document Number: 3GPPEVOLUTIONWP: http://www.freescale.com/files/wireless_comm/doc/white_paper/3GPPEVOLUTIONWP.pdf
3GPP TR 25.913 V8.0.0 (2008-12), “Requirements for Evolved UTRA (E-UTRA) and Evolved UTRAN (E-UTRAN) (Release 8)”
3GPP TS 36.300 v8.7.0, “E-UTRA and E-UTRAN Overall Description; Stage 2”
3GPP TS 36.401 V8.4.0 (2008-12), “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Architecture description (Release 8)”
3GPP TS 36.410 V8.1.0 (2008-12), “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); S1 General aspects and principles (Release 8)”
3GPP TS 36.420 V8.1.0 (2008-12), “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 general aspects and principles (Release 8)”
3GPP TS 36.201 V8.2.0 (2008-12), “Evolved Universal Terrestrial Radio Access (E-UTRA); LTE Physical Layer – General Description (Release 8)”
3GPP Long-Term Evolution (LTE) – Qualcomm Incorporated, January 2008: http://www.qualcomm.com/common/documents/white_papers/3GPP_LTE.pdf
Technical Overview of 3GPP LTE – Hyung G. Myung: http://www.scribd.com/doc/5539254/3gpp-LTE-Overview
LTE Overview – NEC Corporation – By K. Jay Miyahara: http://www.nsma.org/conf2008/Presentation/2-1045-Miyahara-LTE_Overview_NMSA%2021March08_final.pdf
Agilent 3GPP Long Term Evolution: System Overview, Product Development, and Test Challenges: http://cp.literature.agilent.com/litweb/pdf/5989-8139EN.pdf
Ekstrom, H.; Furuskar, A.; Karlsson, J.; Meyer, M.; Parkvall, S.; Torsner, J.; Wahlqvist, M., “Technical solutions for the 3G long-term evolution” Communications Magazine, IEEE Volume 44, Issue 3 , March 2006 Page(s): 38 - 45
http://wiki.hsc.com/LTE
Long Term Evolution (LTE); A Technical Overview – Technical White Paper: http://www.motorola.com/staticfiles/Business/Solutions/Industry%20Solutions/Service%20Providers/Wireless%20Operators/LTE/_Document/Static%20Files/6834_MotDoc_New.pdf
3GPP LTE: Introducing Single - Carrier FDMA – By Moray Rumney, Agilent Technologies: http://cp.literature.agilent.com/litweb/pdf/5989-7898EN.pdf
Single Carrier Orthogonal Multiple Access Technique for Broadband Wireless Communications –Dissertation by Hyung G. Myung: http:// hgmyung.googlepages.com/Hyung_G_Myung_PhD_thesis.pdf
Priyanto, B.E.; Codina, H.; Rene, S.; Sorensen, T.B.; Mogensen, P., “Initial Performance Evaluation of DFT-Spread OFDM Based SC-FDMA for UTR LTE Uplink” Vehicular Technology Conference, 2007. VTC2007-Spring. IEEE 65th 22-25 April 2007 Page(s):3175 - 3179

References
Myung, H.G.; Kyungjin Oh; Junsung Lim; Goodman, D.J., “Channel-Dependent Scheduling of an Uplink SC-FDMA System with Imperfect Channel Information” Wireless Communications and Networking Conference, 2008. WCNC 2008. IEEE March 31 2008-April 3 2008 Page(s):1860 - 1864
Junsung Lim; Myung, H.G.; Kyungjin Oh; Goodman, D.J., “Proportional Fair Scheduling of Uplink Single-Carrier FDMA Systems” Personal, Indoor and Mobile Radio Communications, 2006 IEEE 17th International Symposium on 11-14 Sept. 2006 Page(s):1 - 6
Junsung Lim; Myung, H.G.; Kyungjin Oh; Goodman, D.J., “Channel-Dependent Scheduling of Uplink Single Carrier FDMA Systems” Vehicular Technology Conference, 2006. VTC-2006 Fall. 2006 IEEE 64th 25-28 Sept. 2006 Page(s):1 - 5
Yan Lin; Guangxin Yue, “Channel-Adapted and Buffer-Aware Packet Scheduling in LTE Wireless Communication System” Wireless Communications, Networking and Mobile Computing, 2008. WiCOM '08. 4th International Conference on 12-14 Oct. 2008 Page(s):1 - 4
Ruiz de Temino, L.; Berardinelli, G.; Frattasi, S.; Mogensen, P., “Channel-aware scheduling algorithms for SC-FDMA in LTE uplink” Personal, Indoor and Mobile Radio Communications, 2008. PIMRC 2008. IEEE 19th International Symposium on 15-18 Sept. 2008 Page(s):1 - 6
Saatsakis, A.; Tsagkaris, K.; von-Hugo, D.; Siebert, M.; Rosenberger, M.; Demestichas, P., “Cognitive Radio Resource Management for Improving the Efficiency of LTE Network Segments in the Wireless B3G World” New Frontiers in Dynamic Spectrum Access Networks, 2008. DySPAN 2008. 3rd IEEE Symposium on 14-17 Oct. 2008 Page(s):1 - 5
Jung-Lin Pan; Olesen, R.; Grieco, D.; Chia-Pang Yen, “Efficient Feedback Design for MIMO SC-FDMA Systems” Vehicular Technology Conference, 2007. VTC2007-Spring. IEEE 65th 22-25 April 2007 Page(s):2399 - 2403
Liu, Jin; Wang, Liang; You, Mingli; Wen, Pingping, “A Special Open-Loop Transmit Antenna Selection Mode in the SC-FDMA Systems for 3G LTE” Military Communications Conference, 2007. MILCOM 2007. IEEE 29-31 Oct. 2007 Page(s):1 - 5
Tavangaran, N.; Wilzeck, A.; Kaiser, T., “MIMO SC-FDMA system performance for space time / frequency coding and spatial multiplexing” Smart Antennas, 2008. WSA 2008. International ITG Workshop on Volume , Issue , 26-27 Feb. 2008 Page(s):382 – 386
Zijian Bai; Berkmann, J.; Spiegel, C.; Scholand, T.; Bruck, G.H.; Drewes, C.; Gunzelmann, B.; Jung, P., “On MIMO with successive interference cancellation applied to UTRA LTE” Communications, Control and Signal Processing, 2008. ISCCSP 2008. 3rd International Symposium on 12-14 March 2008 Page(s):1009 - 1013
Ribeiro, C.B.; Hugl, K.; Lampinen, M.; Kuusela, M., “Performance of linear multi-user MIMO precoding in LTE system” Wireless Pervasive Computing, 2008. ISWPC 2008. 3rd International Symposium on 7-9 May 2008 Page(s):410 - 414
LTE-Advanced takes an important step forward- http:// www.telecommagazine.com/Newsglobe/article.asp?HH_ID =AR_4623
3GPP Presentation on the LTE-Advanced as an IMT-Advanced Technology Solution (RP-080756): http://groups.itu.int/Portals/17/SG5/WP5D/Workshop/3GPP%20-%20LTE-Advanced%20as%20an%20IMT-Advanced%20Technology%20Solution%20-%20N%20Magnani.pdf
Progress on “LTE Advanced”- the new 4G standard – By Eiko Seidel, Nomor Research GmbH: http://www.nomor.de/uploads/_c/V1/_cV1fTZl6MtFnAHVXltStg/LTEAdvanced_2008-07.pdf
Parkvall, S.; Dahlman, E.; Furuskar, A.; Jading, Y.; Olsson, M.; Wanstedt, S.; Zangi, K., “LTE-Advanced – Evolving LTE towards IMT –Advanced” Vehicular Technology Conference, 2008. VTC 2008-Fall. IEEE 68th 21-24 Sept. 2008 Page(s):1 – 5.
Single Carrier FDMA – By Hyung G. Myung, May 18, 2008: http://www.scribd.com/doc/13905822/Single-Carrier-FDMA hgmyung.googlepages.com/scfdma.pdf

[email_address] Thank You !

http://3g4g.blogspot.com	1738
http://lte-epc.blogspot.com	1725
http://www.slideshare.net	141
http://lte-epc.blogspot.in	112
http://bytebeats.com	108
http://kupluk2.blogspot.com	69
http://3g4g.blogspot.in	61
http://technota.blogspot.com	49
http://3g4g.blogspot.co.uk	18
http://lte-epc.blogspot.fr	17
http://lte-epc.blogspot.de	15
http://lte-epc.blogspot.co.uk	13
http://lte-epc.blogspot.ca	10
http://3g4g.blogspot.fr	8
http://trendteknology.blogspot.com	8
http://adeprakasa.blogspot.com	7
http://www.3g4g.blogspot.com	7
http://lte-epc.blogspot.com.au	6
http://ad-punkt.nazwa.pl	6
http://translate.googleusercontent.com	6
http://zidan001.wordpress.com	5
http://www.3g4g.blogspot.in	5
http://3g4g.blogspot.com.es	4
http://lte-epc.blogspot.se	4
http://3g4g.blogspot.ca	4
http://lte-epc.blogspot.pt	3
http://lte-epc.blogspot.it	3
http://xss.yandex.net	3
http://static.slidesharecdn.com	3
http://lte-epc.blogspot.fi	3
http://lte-epc.blogspot.jp	2
http://3g4g.blogspot.it	2
http://lte-epc.blogspot.com.br	2
http://3g4g.blogspot.jp	2
http://3g4g.blogspot.de	2
http://www.google.com	2
http://3g4g.blogspot.com.au	2
http://74.125.153.132	1
http://wildfire.gigya.com	1
http://www.ig.gmodules.com	1
http://www.mefeedia.com	1
http://3g4g.blogspot.com.br	1
http://honeypresentations.blogspot.com	1
http://technota.blogspot.com.es	1
http://www.lte-epc.blogspot.in	1
http://3g4g.blogspot.nl	1

LTE - Long Term Evolution

by Arief Gunawan on Nov 19, 2009

Accessibility

Categories

Tags

Upload Details

Usage Rights

46 Embeds 4,184

Statistics

LTE - Long Term Evolution — Presentation Transcript