lte basic introduction

7/29/2019 LTE Basic Introduction

http://slidepdf.com/reader/full/lte-basic-introduction 1/46

All Rights Reserved © Alcatel-Lucent 2006, #####

3GPP Long Term Evolution

Introduction

LTE TIS

2009-12



All Rights Reserved © Alcatel-Lucent 2006, ##### 2 | 3GPP LTE Technology - Overview| Dec 2009

Agenda

1. LTE & 3GPP Standard

2. LTE Network System

3. LTE Key Technologies

4. LTE TDD Characteristics




1. LTE & 3GPP Standard




About 3GPP LTE

Since November 2004, 3GPP has been working on the Long Term

Evolution (LTE) for enhancements to the Universal MobileTelecommunications System (UMTS), and focus on adopting 4Gtechnology.

Specs (Rel-8) were finalized and approved in January 2008.

LTE-Advanced study phase in progress.Target on deployment in 2010. By 2015, subscriptions could

exceed 400 million, and revenues from LTE could representmore than 15% of all mobile revenues.http://www.3gpp1.net/New-UMTS-Forum-report-forecasts

http://www.3gpp1.net/New-UMTS-Forum-report-forecasts













LTE Milestone in 3GPP Standard Evolution

3GPPRelease

Rel’99 Rel’4 Rel’5 Rel’6 Rel’7 Rel’8

UMTS FDD

DCH up to2Mbps

Core Netw.Evolution

FDDrepeaters

1.28McpsTDD

HSDPA

Multimediasub-system

HSUPA

MBMS

HSPA+

i.e. MIMO,CPC, DL 64-QAM, UL16-QAM

LTE

Rel1




3GPP Requirements For LTESpectrum efficiency

DL : 3-4 times HSDPA for MIMO(2,2)

UL : 2-3 times E-DCH for MIMO(1,2)

Frequency Spectrum :

Scalable bandwidth : 1.4, 3, 5, 10, 15, 20MHz

To cover all frequencies of IMT-2000: 450 MHz to 2.6 GHz

Peak data rate (scaling linearly with the spectrum allocation)

DL : > 100Mb/s for 20MHz spectrum allocation

UL : > 50Mb/s for 20MHz spectrum allocation

Capacity 200 users for 5MHz, 400 users in larger spectrum allocations

(active state)

Latency

C-plane : < 100ms to establish U-plane

U-plane : < 10ms from UE to server Coverage

Performance targets up to 5km, slight degradation up to 30km

Mobility

LTE is optimized for low speeds 0-15km/h but

connection maintained for speeds up to 350 or 500km/h

Handover between 3G & 3G LTE Real-time < 300ms

Non-real-time < 500ms




Increased Performances & Reduced Costs with LTE

Latency Throughput Cost per Megabyte*

* Source: Analysis Research, 2006

Mobility

Roaming

LTE

EDGE

HSPA

UMTS384kbps DL

128kbps UL

14.4 Mb/s DL

5.7Mb/s UL

0.06 €

0.03 €

220kbps DL

120ms

60ms

750ms

H/O withGSM

0.005 € >100 Mb/s DL

>50 Mb/s UL<10ms

H/O withGSM,UMTS,CDMA…




LTE landscape




2. LTE Network System




3GPP LTE system architecture

eNB eNB

eNB

MME/SAEGW MME/SAEGW

S1

X2

X2

X2

E-UTRAN

Enhanced

PacketCore

eNodeB cell site node

S1-MME: control plane between eNodeB and MME

S1-U: user plane between eNodeB and SAEGW

S1: interface between an eNB and an EPC, providing an interconnection point betweenthe E-UTRAN and the EPC. It is also considered as a reference point.

X2: logical interface between two eNBs. Whilst logically representing a point to pointlink between eNBs, the physical realization need not be a point to point link.




EUTRAN Network Architecture

LTE-Uu

LTE-Uu

X2C

X2U

X2C

X2U

X2C

X2U

S1-MME

S1-MMES1-MME

S1U

S1U

S1U

UE

UE

eNB

eNBeNB

MME

AGW

IP Transport Network (IP Cloud)

X2C - X2 Cplane S1U - S1 Uplane

X2U - X2 Uplane S1-MME - S1 Cplane

AP - Access Point (for IP cloud)

eUTRAN EPC

APAP

AP AP

AP




Flat Architecture

Low latency

RTT: 10 ms instead of 60 ms for HSPA

Short TTI (1 ms instead of 2ms for HSPA) and the flat architecture

Backhaul based from day 1 on IP / MPLS transport

Node-B Node-B

Node-B

MSC

RNC

SGSN

PSTN

Internet

GGSN

aGW

eNode-B eNode-B

Internet

PSTN

eNode-B




Network Simplification: From 3GPP to 3GPP LTE

3GPP architecture

4 functional entities on thecontrol plane and user plane

3 standardized UP & CP

interfaces

3GPP LTE architecture

2 functional entities on the userplane: eNodeB and ASGW

SGSN control plane functions =>ASGW & MME

RNC control plane functions =>

MME & eNodeB Less interfaces, some functions

will disappear

4 layers into 2 layers

Evolve GGSN integrated

ASGW Moving SGSN functionalities to

ASGW.

RNC evolutions to RRM DB on aIP distributed network forenhancing mobilitymanagement.

GGSN

SGSN

RNC

NodeB

ASGW

eNodeB

MMF

GGSN

SGSN

RNC

NodeB

Control plane User plane

ASGW

eNodeB

MMF

AGW

eNodeB

MME

Control plane User plane




ys em rc ec ure vo u on Mobility by “Single Gw” or Mobile IP

PCRF – Policy and Charging Rules Function

GERAN

Other IP Access3GPP or non-3GPP

(e.g. I-WLAN, 3GPP2, LTE also)

GGSN

MIP HA

PS & Evolved PS Core

ASGW

IMS

L3 AAA

(e.g. PCRF)

Multimedia Stratum

Access System Stratum

NetworkStratum(AIPN)

UTRAN

GAN

Evolved

UTRAN




S1 Architecture

Key points

Flex Architecture for bothinterfaces S1-U and S1-MME

MME and SAE GW can besplit in two logical nodes orcombined in the same AGW

eNB eNB eNB eNB

MME/

SAEGW

MME/

SAEGW

MME/

SAEGW

MME/

SAEGW

Overlapping regionPool A Pool B

S1

2 entities for control plane: eNB & MME (S1-MME interface)

eNB: UMTS NodeB plus UMTS RNC (RRC, Radio Bearer Management…)

MME: UMTS MM and SM functions2 entities for user plane: eNB & SAE GW (S1-U interface)

eNB: UMTS NodeB plus UMTS RNC (PDCP/RLC/MAC…)

SAE GTW: (Serving Gateway) UMTS packet core user plane

No Macro-diversity




Functional Mapping (from TR 25.813)

internet

eNB

RB Control

Connection Mobility Cont.

eNB Measurement

Configuration & Provision

Dynamic Resource

Allocation (Scheduler)

PDCP

PHY

MME

Serving Gateway

S1

MAC

Inter Cell RRM

Radio Admission Control

RLC

E-UTRAN EPC

RRC

Mobility Anchoring

SAE Bearer Control

Idle State Mobility

Handling

NAS Security

MME Functions

Idle mode mobility

Tracking area update

Maintenance of equivalent tracking areas

Idle mode access restrictions

Security Key management

S1 connection establishment

Idle to active mode transition

Session management

RAB and QoS

S1 handling during HO

SAE GW radio related functionality

Idle S1 GTP bearer end point

QoS handling & tunnel mgt

S1 path switch during Handover




Functional Mapping (from TR 25.813)

LTE functions in eNode-B

Selection of aGW at UE attachment

Routing towards aGW at UE initial access

NAS messaging encapsulated by RRC for tx over radio

Scheduling and transmission of paging messages

Scheduling and transmission of System Information

Dynamic allocation of resources to UEs in both ULand DL

Configuration and provision of eNB measurements Radio Bearer Control


Access restrictions in Active state

Connection Mobility Control in LTE_ACTIVE state

Active mode Handover handling

RRC, header compression, encryption, RLC, MAC,PHY

Security of User plane and RRC

Encryption of both in PDCP, integrity check of RRC

Scheduling and associated QoS handlinginternet

eNB

RB Control


eNB Measurement


Dynamic Resource


PDCP

PHY

MME

Serving Gateway

S1

MAC

Inter Cell RRM


RLC

E-UTRAN EPC

RRC

Mobility Anchoring

SAE Bearer Control

Idle State Mobility

Handling

NAS Security




RRM Functions (1/3)

internet

eNB

RB Control


eNB Measurement


Dynamic Resource


PDCP

PHY

MME

Serving Gateway

S1

MAC

Inter Cell RRM


RLC

E-UTRAN EPC

RRC

Mobility Anchoring

SAE Bearer Control

Idle State Mobility

Handling

NAS Security

Inter-Cell Interference Coordination (ICIC):

Managing the radio resources(notably the radio resource blocks)

such that inter-cell interference is

kept under control

Load Balancing (LB):

Influence the traffic load

distribution in such a manner that

radio resources remain highly

utilized and the QoS of in-progress

sessions are maintained to the

possible extent (may result in

handover decisions)Inter-RAT Radio Resource Management:

In connection with inter-RAT

mobility (taking into account the

involved RAT resource situation, UE

capabilities & operator policies)




RRM Functions (2/3)

internet

eNB

RB Control


eNB Measurement


Dynamic Resource


PDCP

PHY

MME

Serving Gateway

S1

MAC

Inter Cell RRM


RLC

E-UTRAN EPC

RRC

Mobility Anchoring

SAE Bearer Control

Idle State Mobility

Handling

NAS Security

Connection Mobility Control (CMC):

Management of radio resources inconnection with idle or active

mode

Mobility of radio connections:

handover decisions based on UE &

e-NodeB measurements +

potentially: neighbour cell load,

traffic distribution, transport & HW

resources & operator defined

policies

Radio Bearer Control (RBC):

Establishment, maintenance &release of Radio Bearers

Taking into account overall

resource situation, QoS

requirements of in-progress

sessions and of the new service)

Radio Admission Control (RAC):




RRM Functions (3/3)

internet

eNB

RB Control


eNB Measurement


Dynamic Resource


PDCP

PHY

MME

Serving Gateway

S1

MAC

Inter Cell RRM


RLC

E-UTRAN EPC

RRC

Mobility Anchoring

SAE Bearer Control

Idle State Mobility

Handling

NAS Security

Packet Scheduling (PSC)

Allocate/De-allocate resources(including buffer, processing

resources & resource blocks) to UP

& CP packets including:

Selection of RB, whose packets are to

be scheduled

Managing the necessary resources

(e.g. power levels, specific resource

blocks)




LTE ARCHITECTURE – Control Plane Layout over S1

eNB

PHY

UE

PHY

MAC

RLC

MAC

MME

RLC

NAS NAS

RRC RRC

PDCP PDCP

UE eNode-B MME




LTE ARCHITECTURE – Control Plane Layout over S1

eNB

PHY

UE

PHY

MAC

RLC

MAC

MME

RLC

NAS NAS

RRC RRC

PDCP PDCP

UE eNode-B MME

RRC sub-layer performs:

Broadcasting

Paging

Connection Mgt Radio bearer control

Mobility functions

UE measurement reporting & control

PDCP sub-layer performs:

Integrity protection & ciphering

NAS sub-layer performs:

Authentication

Security control

Idle mode mobility handling

Idle mode paging origination




LTE ARCHITECTURE – User Plane Layout over S1

UE eNode-B MME

eNB

PHY

UE

PHY

MAC

RLC

MAC

PDCPPDCP

RLC

SAE Gateway




LTE ARCHITECTURE – User Plane Layout over S1

UE eNode-B MME

eNB

PHY

UE

PHY

MAC

RLC

MAC

PDCPPDCP

RLC

SAE Gateway

RLC sub-layer performs:

Transferring upper layer PDUs

In-sequence delivery of PDUs

No error correction through ARQ Duplicate detection

Flow control

Concatenation/re-assembly of packets

PDCP sub-layer performs:

Header compression

Ciphering

MAC sub-layer performs:

Scheduling

Error correction through HARQ

Priority handling across UEs & logicalchannels

In-sequence delivery of RLC PDUs

Multiplexing/de-multiplexing of RLC

radio bearers into/from PhCHs on TrCHs

Physical sub-layer performs:

DL: ODFMA, UL: SC-FDMA

HARQ

UL power control

Multi-stream transmission & reception (i.e. MIMO)




From UE Power-up to Active Connection

AcquisitionPower-up

Idle

Access

Registration

Traffic

LTENetwork

Frequency/Timing acquisition

p-SCH, s-SCH & Reference Signal

Cell Id determination

Cell search procedure

SIB message

CCPCH/PDSCH

Message from UE (origination, registration,…)

PRACH/PUSCH

Registration procedure

PDSCH/PUSCH

DL traffic

PDSCH

UL traffic

PUSCH




3. LTE Key Technologies




Innovative Technologies Emerging in Standards

1st Commercial launches

20082007 Beyond2006 2009

3G LTE

All-IPOFDM MIMO AAS

WiMAX 802.16m

All-IPOFDM MIMO

WiMAX 802.16e-2005

All-IPOFDM MIMOAAS AAS

CDMA2000 EV-DO Rev.A

IP transport

EV-DO Rev.C

All-IPOFDM MIMO AAS

HSDPA / HSUPA

IP Transport

HSPA+

MIMO All-IP

OFDM, All-IP, MIMO & AASare the key cornerstones of new & future wireless standards




Key LTE Features to Overcome Challenges

OFDMA

Increased spectral efficiency

Simplified Rx design Cheaper UE

Scalable - Go beyond 5MHz limitation

MIMO: antenna technology

Multiple-input, multiple-output

Overcome multi-path interference

Peak rate breakthrough

IP Core: flat, scalable

Low latency: 10 ms (60 ms for HSPA)

Short TTI: 1 ms (2ms for HSPA)

Backhaul based on IP / MPLS transport

Fits with IMS, VoIP, SIP

Mobile

Local

Fixed

UMTS / HSDPA

CDMA / EVDO

WiMAX 16e

802.11, Mesh

WiMAX 16d

DSL / Cable

PSTN

Internet

Corporate

POTS

IP

Ethernet

OFDM

MIMO

Mobility

Access

IMS

VoIP

SIP

Core

0 5 10 15 20 25 30 35 400

2

4

6

8

10

12

14

16

18

20

SNR [dB]

T h r o u g h p u t [ M b i t / s ]

LTE-OFDMA, 5MHz, SCME, urban macro, dtx

=10, drx

=0.5, 30km/h, 16-QAM, real CE (lin. i nterp.)

MIMO (SCW), R=1/3

MIMO (MCW), R=1/3

SISO, R=1/3MIMO (SCW), R=2/3

MIMO (MCW), R=2/3

SISO, R=2/3

SISO,10Mbps/5MHz

MIMO 2x2,20Mbps/5MHz

16QAM




Why OFDMA?

Suitable for MIMO implementation

Ease Time & Frequency scheduling Less receiver complexity

Robust to frequency-selective fading

Robust to Inter-Symbol Interference (i.e. ISI)

High data rates

t

Mobile

environment

t

+ ISI

t

• Multi-path

• High delayspread

• Short symbol duration

• High-order modulations

Low inter-symbol distance




Frequency

OFDMA Principle

Sub-carrier spacing = Δf

Power

N-OFDM Symbolduration

Bandwidth

User#1 User#2 User#3 User#4




LTE Access Technologies OFDM

eNode-BLTE UE

FDD

UL Bdw DL Bdw

Frequence duplex

TDDTime duplex

Time

DL slotUL slot… …

Frame




UMTS LTE SC-FDMA Transmitter/receiver

M A C

I n t e r f a c e

ChannelCoding

Scrambling Modulation

Scrambling Modulation Spread

USCH

data

Control

data

Demodulation reference signal

generation (for PUSCH & PUCCH)

Resource

Element

Mapper

SC-FDMA

signal

generation

LTE Channel

SC-FDMA

signal de-

generation

Resource

Element

De-

mapper

Frequency offset

estimation &

compensation

Demodulation

Reference Signal

Channel

Estimation

Transform

decodingDemodulation

De-

scrambling

Channel

Decoding

M A C

I n t e r f a c e

USCH

data

Equalization

for PUCCHDe-spreadDemodulation

De-

scrambing

UCCH

data

LTE User Equipment

LTE eNodeB

TransformPrecoder

Equalization

for PUSCH

(2048*7+160+144*6)*2 =

30720

2048*14 = 28672

12*6*12 = 864

12*6*12 = 864864*2 = 1728864*2 = 1728

568

12*7*2 =

168

20 20 1010*12+12*

2*2 = 168

(2048*7+160+144*6)*2 =

30720

2048*14 = 28672




OFDM Advantages & Drawbacks

Advantages

Can easily adapt to severe channel conditions without complexequalization

Robust against narrow-band co-channel interference

Robust against Intersymbol interference (ISI) and fading

High spectral efficiency Efficient implementation using FFT

Low sensitivity to time synchronization errors

Tuned sub-channel receiver filters are not required (unlike

traditional FDM)

Facilitates Single Frequency Networks

Drawbacks

Sensitive to Doppler shift and to frequency synchronization problems

High Peak-to-Average Power Ratio




MIMO Principle

Transmission

Of several independent data streams in parallel

Over uncorrelated antennas (i.e. separated by 10)

Reception

Over NTx x NRx (ideally) uncorrelated paths

Theoretical maximum rate increase factor = Min (NTx ,

NRx)

In a rich scattering environment; no gain in LOS environment

Practical gain in urban areas = 1.2 to 1.5 for 2x2 MIMO

Boosting capacity (DL and UL) and peak burst rate (DL),

Sensitive to SINR




MIMO in 3GPP Rel’8

In DL: 1, 2 or 4 TX antennas and 1, 2 or 4 RX antennas

Allowing multi-layer transmissions with up to four streams MU-MIMO: allocation of different streams to different users

• MU-MIMO

• SU-MIMO

In UL:

• only MU-MIMO no SU-MIMOChoice for MIMO mode at the Node B side

Restricted by the UE capability (e.g. number of RX antennas)

Adapted slowly (e.g. once in a com, or every xiple of 100ms)

Rank adaptation (and/or antenna subset selection) is supported for evaluation

The number of codewords transmitted to a UE is controlled through rank adaptation

MU-MIMO to a UE is determined either dynamically or semi-statically

Candidates for the UE feedback information

MIMO channel state information

Channel quality indicator (CQI), which may be used by the Node B to

decide a MCS level(s).




Combining

Rx packets

Hybrid-ARQ Principle

Serving

RNC Node-B UE

Serving

RNC

Node-B

UE

R99 on a DCH channelThe erroneous block is deleted!

R5 on theHS-DSCH channelThe erroneous block is stored for

recombination

Combining

Rx packets

eNode-B UE

LTE H-ARQThe RTT is shorter due to eNode-B

concentration




LTE RRC States

RRC_Idle

(Idle state)

RRC_CONNECTED

(active state)

RRC_NULL

(detached state)

De-registration / PLMN change

Registration

Traffic / HO

• Cell re-selection

• Paging

• TA update

No MM context of UE in eNB / Core

network




4. LTE TDD Characteristics

http://images.google.com/imgres?imgurl=http://sipan.inictel.gob.pe/internet/tx/imag/inst/3gpp.gif&imgrefurl=http://sipan.inictel.gob.pe/internet/tx/standard/radiocom.htm&usg=__4E4z61zD9G1hssSD2edOYsh2IYI=&h=453&w=772&sz=9&hl=en&start=5&um=1&tbnid=DDIlW1NFrNTX-M:&tbnh=83&tbnw=142&prev=/images%3Fq%3D3gpp%26hl%3Den%26rlz%3D1Q1GGLD_en-GBFR326DE327%26sa%3DN%26um%3D1




TD-LTE Emerging from the FDD Shadow

TD-LTE was a key part of overall LTE standard to prevent repeat of 3G TDD failure

Alignment achieved to both Europe TDD and China TD-SCDMA, achieved to ensure easyevolution and spectrum access

Standard/LSTI: though TD-LTE standard started later than LTE FDD, China Mobile hassuccessfully accelerated the TDD IOT timeline to be in line with FDD

TD-LTE led by China Mobile

TD-LTE is an important part of “Next Generation BB Wireless Network” identified bystate M&L Projects, which is aligned with China’s Innovation Policy to be “InnovationCountry”

CMCC driving TD-LTE as its next generation broadband wireless-IP network to replaceGSM and TD-SCDMA and compete with WCDMA/LTE FDD operators

Unique Global Alignment

Vodafone, CMCC, Verizon have a joint agreement to promote the success of TD-LTE

United to drive success of ecosystem

Other operator groups asking for RFx and Trials to evaluateTD-LTE to allow use of unused spectrum assets

http://images.google.com/imgres?imgurl=http://sipan.inictel.gob.pe/internet/tx/imag/inst/3gpp.gif&imgrefurl=http://sipan.inictel.gob.pe/internet/tx/standard/radiocom.htm&usg=__4E4z61zD9G1hssSD2edOYsh2IYI=&h=453&w=772&sz=9&hl=en&start=5&um=1&tbnid=DDIlW1NFrNTX-M:&tbnh=83&tbnw=142&prev=/images%3Fq%3D3gpp%26hl%3Den%26rlz%3D1Q1GGLD_en-GBFR326DE327%26sa%3DN%26um%3D1

http://www.google.co.uk/imgres?imgurl=http://routingbyrumor.files.wordpress.com/2008/01/verizon-logo-470x310.jpg&imgrefurl=http://routingbyrumor.wordpress.com/2008/01/09/hey-verizon-when-will-fios-be-available-in-my-neighborhood/&h=309&w=470&sz=23&tbnid=c3UuBUUOZLd9yM:&tbnh=85&tbnw=129&prev=/images%3Fq%3Dverizon%2Blogo&hl=en-GB&usg=__bR3mwJPpXRyb4msXvQpTofhO6Yg=&ei=tvpRSqTiO962jAfD5dXABQ&sa=X&oi=image_result&resnum=1&ct=image

http://images.google.co.uk/imgres?imgurl=http://www.techgadgets.in/images/vodafone-logo-sept07.jpg&imgrefurl=http://www.techgadgets.in/mobile-phones/2007/21/vodafone-claims-to-have-a-chance-to-sell-iphones/&usg=__Z1iI4JWC7d6McnZUdfGjSsvDE2Y=&h=259&w=320&sz=26&hl=en&start=3&um=1&tbnid=JcnSvHdWzH9NXM:&tbnh=96&tbnw=118&prev=/images%3Fq%3Dvodafone%2Blogo%26hl%3Den%26rlz%3D1T4GGIH_en%26um%3D1




Commonalities between TD-LTE and LTE FDD

The LTE infrastructure includes …

Terminal, eNB, MME, PCRF, sGW and PDN GW

TD-LTE and LTE FDD are mainly different by dedicated realization of physical layer

Hence, they are invisible to the higher layers (except for

parameter configurations). The MME, PCRF and xGW are virtually

identical for FDD and TDD systems

Differences are in eNB and terminals with respect to FDD and TDD due to the differencein air interface design/physical layer. Therefore, it is beneficial to exploit this

similarity to build one system that can support FDD and/or TDD.

MME

PCRF

SGW PDN GW




Main Differences between TD-LTE and LTE FDD Summary

TD-LTE needs to support various TDD UL/DL allocations & needs to support

coexistence with other TDD systems Resulting TD-LTE differences

Frame structure (3GPP TS36.300/TS36.211)

Introduction of “frame structure 2” for TD-LTE

Introduction of special subframe for switching from DL to UL and coexistence withother TDD systems

System information

Cell broadcasts the TDD UL/DL configuration information

Random Access

Additional short random access format for special subframe/UpPTS

Multiple random access channels in a subframe

UL multi TTI scheduling

Multi-subframe scheduling for UL

For heavy UL configurations to save DL control overhead

ACK/NACK bundling/multiplexing on UL control channel

For heavy DL configurations to save UL control overhead

H-ARQ process number & timing

Variable number of H-ARQ processes depending on the UL/DL allocation

Power control timing

SRS configuration

Different TD-LTE spectrum allocation (3GPP TS36.101)




LTE Radio Frame Structure

Two types of radio frame

1. Type 1 Applicable to both FDD and TDD

2. Type 2

Applicable to TDD only

#0 #1 #2 #3 #19

One slot, T slot = 15360T s = 0.5 ms

One radio frame, T f = 307200T s=10 ms

#18

One subframe

DwPTS: Pilot for DL

UpPTS: Special uplink time slot

One slot,

T slot=15360T s

GP UpPTSDwPTS

One radio frame, T f = 307200T s = 10 ms

One half-frame, 153600T s = 5 ms

30720T s

One subframe,

30720T s

GP UpPTSDwPTS

Subframe #2 Subframe #3 Subframe #4Subframe #0 Subframe #5 Subframe #7 Subframe #8 Subframe #9

TD-LTE Frame Structure - Uplink and Downlink




p

Configuration – 3GPP TS36.211

Configuration 1 is supported in first release.

Configuration 2 is planned in TLA2.1 (2010 Q2).




H-ARQ

Unlike FDD, where the number of HARQ processes is always 8, in TDD the number of

HARQ proceses depends on the UL/DL configuration.

In TDD, time between grant and corresponding UL transmission, and between the ULtransmission and the corresponding Ack/Nack varies with a minimum of 4 subframes.

In TDD, when subframes allocated to UL exceed DL, multiple PHICH can be transmitted in

same DL subframe corresponding to multiple UL subframes.

In TDD, when subframes allocated to UL exceed DL, UL grant sent in DL subframe can

correspond to transmission in multiple UL subframes as indicated by UL index in UL grant.

Uplink H-ARQ

Downlink H-ARQ

Variable number of H-ARQ processes

depending on the UL/DL allocation

Unlike FDD, where the number of HARQ processes is always 8, in TDD the number of

HARQ proceses depends on the UL/DL configuration.

In TDD, time between the DL transmission and the corresponding Ack/Nack varies with a

minimum of 4 subframes.In TDD, when subframes allocated to DL exceed UL, multiple Ack/Nacks are bundled or

multiplexed into one UL subframes on PUCCH or PUSCH.

New field (DAI - Downlink Index Assignment) is added to the DCI information to indicate

the number of DL transmissions to be grouped in one Ack/Nack response/




Frequency Bands & Bandwidths – 3GPP TS36.101

UMTS FDD

frequency band(60 MHz)

New IMT-2000frequency band

(70 MHz)

TD-SCDMA mainfrequency band

(15 MHz)

TD-SCDMAsupplementaryfrequency band

(40 MHz)

TD-SCDMAsupplementaryfrequency band

(100MHz)

New IMT-2000

frequency band

(100MHz)

New IMT-2000

frequency band

(50MHz)

Additional bands for approval in Rel 9

FDD Band 20 to be integrated (UL 3410-3500 MHz / DL 3510-3600 MHz)TDD Band 41 to be integrated (3400-3600 MHz)



www.alcatel-lucent.com

lte basic introduction

Documents