3GPP LTE presentation Kyoto May 22rd 2007

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3GPP LTE presentation

3GPP TSG RAN Chairman3GPP TSG RAN Chairman

3GPP LTE presentation Kyoto May 22rd 2007

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• Presentation Overview– LTE Introduction– Network Architecture– The access network

• Physical Layer• Layer 2 and above over the radio interface

– Control Plane

– User Plane

• Interface towards the Core Network

– Conclusion

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LTE targets• Significantly increased peak data rates• Increased cell edge bitrates• Improved spectrum efficiency• Improved latency• Scaleable bandwidth• Reduced CAPEX and OPEX• Acceptable system and terminal complexity, cost and

power consumption• Compatibility with earlier releases and with other systems• Optimised for low mobile speed but supporting high mobile

speed

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Peak data rate• Goal: significantly increased peak data rates,

scaled linearly according to spectrum allocation• Targets:

– Instantaneous downlink peak data rate of 100Mbit/s in a 20MHz downlink spectrum (i.e. 5 bit/s/Hz)

– Instantaneous uplink peak data rate of 50Mbit/s in a 20MHz uplink spectrum (i.e. 2.5 bit/s/Hz)

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Mobility• The Enhanced UTRAN (E-UTRAN) will:

– be optimised for mobile speeds 0 to 15 km/h– support, with high performance, speeds between 15 and

120 km/h– maintain mobility at speeds between 120 and 350 km/h

• and even up to 500 km/h depending on frequency band

– support voice and real-time services over entire speed range

• with quality at least as good as UTRAN

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3GPP LTE presentationSpectrum issues• Spectrum flexibility

– E-UTRA to operate in 1.25, 1.6, 2.5, 5, 10, 15 and 20 MHz allocations…hence allowing different possibilities for re-farming already in use spectrum

– uplink and downlink…– paired and unpaired

• Co-existence– with GERAN/3G on adjacent channels– with other operators on adjacent channels– with overlapping or adjacent spectrum at

country borders– Handover with UTRAN and GERAN– Handover with non 3GPP Technologies (CDMA 2000,

WiFi, WiMAX)

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• Network Architecture

IMS

TE MT UTRAN

SMS-SCEIRTE MT

BillingSystem*

R UmGERAN

WAG

Uu

HLR/AuC* HSS*

R

C

Wn Wp

Wu

WLANUE

Ww

Intranet/

InternetWa

Wm

Wf

Iu

Gn

Gb, Iu

GfGr

Gd

Ga

GiGn/Gp

Gc

SMS-GMSCSMS-IWMSC

WiOCS*

SGSN

SGSN

Note: * Elements duplicated for picture layout purposes only, they belong to the same logical entity in the architecture baseline.

** is a reference point currently missingTraffic and signalingSignaling

HLR/AuC*

3GPP AAAProxy

GaGy

CDF

CGF*

3GPP AAAServer

PCRF AF

Rx+ (Rx/Gq)

Gx+ (Go/Gx)

OCS*

UE

P-CSCFMw

Cx Dx

Wa

Wg

Gm

SLFHSS*

CSCF

MRFP

IMS-MGW

Wo

D/Gr

Dw

Mb

PDG

CGF*

WLAN AccessNetwork

Wx

MbGGSN

Wz

Wd

BM-SCGmb

Gi

MSC

Gs

PDN

**

BillingSystem*

Wf

Wy

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ePDGEvolved Packet Core

GPRS Core

Trusted non 3GPP IP Access

WLAN3GPP IP Access

S2b

WLANAccess NW

S5b

IASA

S5a

SAE

Anchor

3GPP

Anchor

S4

SGiEvolved RAN

S1

Op.

IP

Serv.

(IMS,

PSS,

etc…)

Rx+

GERAN

UTRAN

Gb

Iu

S3

MME

UPE

HSS

PCRF

S7

S6

SGSN

S2a

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The access network• Generality

– The access network is simplified and reduce to only the Base Station called eNode B

– Physical layer is based on SC FDMA for the Uplink and OFDMA for the Downlink

– Tow modes FDD and TDD considered– MBMS part of the study– Ciphering is handled within the eNode B

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• Physical Layer– Overview

Radio Resource Control (RRC)

Medium Access Control(MAC)

Transport channels

Physical layer

Con

trol

/ M

easu

rem

ents

Layer 3

Logical channelsLayer 2

Layer 1

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• Physical layer details– The Layer 1 is defined in a bandwidth agnostic

way, allowing the LTE Layer 1 to adapt to various spectrum allocations.

– The generic radio frame for FDD and TDD has a duration of 10ms and consists of 20 slots with a slot duration of 0.5ms. Two adjacent slots form one sub-frame of length 1ms. A resource block spans either 12 sub-carriers with a sub-carrier bandwidth of 15kHz or 24 sub-carriers with a sub-carrier bandwidth of 7.5kHz each over a slot duration of 0.5ms.

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• Physical Layer details (continued)– The physical channels defined in the downlink are the

Physical Downlink Shared Channel (PDSCH), the Physical Downlink Control Channel (PDCCH) and the Common Control Physical Channel (CCPCH). The physical channels defined in the uplink are the Physical Uplink Shared Channel (PUSCH) and the Physical Uplink Control Channel (PUCCH).

– In addition, signals are defined as reference signals, primary and secondary synchronization signals or random access preambles.

– The modulation schemes supported in the downlink are QPSK, 16QAM and 64QAM, and in the uplink QPSK, 16QAM and 64QAM. The Broadcast channel use only QPSK

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• Physical Layer (Continued)– The channel coding scheme for transport

blocks in LTE is Turbo Coding with a coding rate of R=1/3, two 8-state constituent encoders and a contention-free quadratic permutation polynomial (QPP) turbo code internal interleaver. Trellis termination is used for the turbo coding. Before the turbo coding, transport blocks are segmented into byte aligned segments with a maximum information block size of 6144 bits. Error detection is supported by the use of 24 bit CRC.

– Coexistence scenarios have been already done for the downlink and result can be found in TR 36.942

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• Physical Layer (Continued)– The generic frame structure is applicable to

both FDD and TDD. Each radio frame is long and consists of 20 slots of length , numbered from 0 to 19 consists of 20 slots of length , numbered from 0 to 19. A sub-frame is defined as two consecutive slots where sub-frame consists of slots and

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• Layer 2 and above over the radio interface– Overall architecture

eNB

MME/SAE Gateway MME/SAE Gateway

eNB

eNB

S1 S1

X2 E-UTRAN

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• Layer 2 and above over the radio interface– The eNode B hosts the following functions:

• Functions for Radio Resource Management: – Radio Bearer Control,

– Radio Admission Control,

– Connection Mobility Control,

– Dynamic allocation of resources to UEs in both uplink and downlink (scheduling);

• IP header compression and encryption of user data stream;

• Selection of an MME at UE attachment;

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• Layer 2 and above over the radio interface

Segm.ARQ

Multiplexing UE1

Segm.ARQ

...

HARQ

Multiplexing UEn

HARQ

BCCH PCCH

Scheduling / Priority Handling

Logical Channels

Transport Channels

MAC

RLCSegm.ARQ

Segm.ARQ

PDCPROHC ROHC ROHC ROHC

Radio Bearers

Security Security Security Security

...

: Layer 2 Structure at the eNode B

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• Layer 2 and above over the radio interface– For the UE two states are considered

• RRC_IDLE where:• - UE specific DRX configured by NAS;• - Broadcast of system information;• - Paging;• - Cell re-selection mobility;• - The UE shall have been allocated an id which uniquely

identifies the UE in a tracking area;– - No RRC context stored in the eNode B .

• RRC_CONNECTED where:• - UE has an E-UTRAN-RRC connection;• - UE has context in E-UTRAN;• - E-UTRAN knows the cell which the UE belongs to;• - Network can transmit and/or receive data to/from UE;• - Network controlled mobility (handover);• - Neighbour cell measurements;

– - At PDCP/RLC/MAC level:– - UE can transmit and/or receive data to/from network;– - UE monitors control signalling channel for shared data

channel to see if any transmission over the shared data channel has been allocated to the UE;

– - UE also reports channel quality information and feedback information to eNode B;

– - DRX/DTX period can be configured according to UE activity level for UE power saving and efficient resource utilization. This is under control of the eNode B

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• Interface towards the Core network– Generalities

• Two interfaces:– S1 for the Control plane

– X1 for the User plane

• Additional interface in between eNode Bs: X2– Including both Control and User plane

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• Interface towards the Core network

internet

eNB

RB Control

Connection Mobility Cont.

eNB MeasurementConfiguration & Provision

Dynamic Resource Allocation (Scheduler)

PDCP

PHY

MME

SAE Gateway

S1MAC

Inter Cell RRM

Radio Admission Control

RLC

E-UTRAN EPC

RRC

Mobility Anchoring

SAE Bearer Control

Idle State Mobility Handling

NAS Security

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• Interface towards the Core network

• For the X1 interface Still under investigation

SCTP

IP

Data link layer

S1-AP

Physical layer

S1 Interface Control Plane (eNB-MME)

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• eNode B X2 Interface– This interfaces allows inter-eNode B handover

X2 Interface Control Plane

SCTP

IP

Data link layer

X2-AP

Physical layer

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3GPP LTE presentationConclusion

• Lot of progress made recently are not incorporated in this presentation

• However the timescale for completion of the specification is still foreseen to be in September 2007

• All documentation referred to is available

At : http://www.3gpp.org/ftp/Specs

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Thanks for your attention

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Annex• Structure of the documentation for the

physical layer specification

36.211 Physical Channels and

Modulation

36.212 Multiplexing and channel

coding

36.213 Physical layer procedures

36.214 Physical layer – Measurements

To/From Higher Layers

Documents

3GPP LTE presentation Kyoto May 22rd 2007