chap 1. stc lte enb overview

Distribution

EnglishED01

Jae ho, Lee

Customer Training Center

http://www.samsung.co.kr/

Samsung Confidential Information. Official Commitment will be made in a formal form. Up to the best of Samsung’s knowledge 2Samsung Confidential Information. Official Commitment will be made in a formal form. Up to the best of Samsung’s knowledge

Intro

Network Architecture

Multiple Access

Frame Structure

Multiple Antenna Technique

LTE Evolution

Contents

Samsung Confidential Information. Official Commitment will be made in a formal form. Up to the best of Samsung’s knowledge 3

Intro


Demand for high-data-rates

Improved system capacity & coverage

Reduced cost for the operator

UTRA : Universal Terrestrial Radio AccessUTRAN: UTRA Radio Access Network

Reduced Latency

LTE Background

Enhancement ofUTRA & UTRAN

<Source: www.3gpp.org>

LTE Definition and HistoryR99 Rel4 Rel5 Rel6 Rel7 Rel8 Rel1

0

WCDMA HSDPA HSPA HSPA evolution

LTE LTE-advanced


Peak data rate100 Mbps (DL) / 50 Mbps (UL)

Baseline: 20 MHz BW, 1TX & 2RX UE

Significantly reduced latency

Control-plane latency

– Idle ↔ active : < 100 ms

– dormant ↔ Active: < 50 ms

User-plane latency : < 5 ms in unload condition for small IP packet

Significantly improved throughput & spectrum efficiency

2 ~ 4 times Release 6 HSPA

Spectrum flexibility

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

Camped-state (idle)

Active (Cell_DCH)

Dormant (Cell_PCH)

Less than 100msec

Less than 50msec

Requirements of LTE (1/2) [Ref: TR 25.913]


MobilityOptimized for low mobile speed 0 ~ 15 km/h

15 ~ 120 km/h should be supported with high performance

Connection maintained at speeds 120 ~ 350 km/h (or even up to

500 km/h)

Support for inter-working with existing 3G systems and non-3GPP systems

Reduced CAPEX and OPEX including backhaul

Efficient support of the various types of services, especially from the PS-domain

Web-browsing, FTP, video-streaming, VoIP

Requirements of LTE (2/2) [Ref: TR 25.913]


LTE Standard Specifications

Specification index Description of contents

TS 36.100 seriesEquipment Requirements:

Terminals, Base stations, and Repeaters

TS 36.200 series

Layer 1 (Physical layer):

Physical channels, Modulation, Multiplexing, Channel

coding, etc.

TS 36.300 series

Layers 2 and 3:

Medium Access Control, Radio Link Control, and Radio

Resource Control.

TS 36.400 seriesNetwork Signaling & Interfaces:

Architecture, S1, X2 Interfaces, etc.

TS 36.500 series UE equipment conformance testing

Free Download from http://www.3gpp.org/ftp/Specs/html-info/36-series.htm


FDD TDD

TD-LTE FundamentalLTE FDD

A paired frequency band allocation

Uplink and downlink selected from different frequency bands

LTE TDDEnables use of unpaired frequency bands

The same frequency band for UL and DL, divided in time

Channel Reciprocity

TD-LTE and LTE FDD Differencesolely a physical layer manifestation and therefore invisible to

higher layers

there are no operational differences between the two modes in the

system architecture.


E-UTRA Operating Band

FDD - frequency division duplex

TDD - time division duplex


HARQ and control signaling

HARQ ACK/NACKFor FDD, the acknowledgement of data received in sub-frame n is

transmitted in sub-frame n+4

For TDD, the acknowledgement obviously cannot be transmitted until

an uplink sub-frame occurs

Multiple UL ACK/NACK TransmissionFor, DL heavy case, the reception of several downlink sub-frames may

need to be acknowledged in a single uplink sub-frame.

ACK/NACK Bundling

- Combines the acknowledgements in time domain from multiple

hybrid-ARQ processes

ACK/NACK Multiplexing

- Combines the acknowledgements in codeword domain from multiple

hybrid-ARQ processes.


Network Architecture


Embedded LaptopDongle typeMobile PhoneSmartphone

WSM

Base Station Base Station Base Station Base Station

MME

LSM-CACR S-GW

P-GW (HA)

WiMAX + LTE Network Architecture


LTE Network Architecture II

NodeBNodeB

RNC

NodeBNodeB

RNC

GGSN

SGSN

• RNC: Radio Network Controller• SGSN: Serving GPRS Support Node• GGSN: Gateway GPRS Support Node

eNB

MME

S-GW/P-GW

MME

S-GW/P-GW

eNB

eNB

S1

S1

S1

S1

X2

X2

X2

E-UTRAN

EPC

3G UMTS LTE

* Source: 3GPP TS 36.300

• eNB: evolved NodeB• MME: Mobility Management Entity• S-GW: Serving Gateway• P-GW: PDN (Packet Data Network) Gateway• EPC: Evolved Packet Core

Entity Function

eNB All radio interface functions, Resource allocation

MME Manages mobility, UE identity, Security parameters

S-GW Terminates the interface towards E-UTRAN

P-GW Terminates the interface towards PDN, UE IP address allocation


Interface & Protocol Stack

Serving GW PDN GW

S5/S8a

GTP-U GTP-U

UDP/IP UDP/IP

L2

Relay

L2

L1 L1

PDCP

RLC

MAC

L1

IP

Application

UDP/IP

L2

L1

GTP-U

IP

SGi S1-U LTE-Uu

eNodeB

RLC UDP/IP

L2

PDCP GTP-U

Relay

MAC

L1 L1

UE

SCTP

L2

L1

IP

L2

L1

IP

SCTP

S1-MME eNodeB MME

S1-AP S1-AP

NAS

MAC

L1

RLC

PDCP

UE

RRC

MAC

L1

RLC

PDCP

RRC

LTE-Uu

NAS Relay

User plane Protocol Stack

Control plane Protocol Stack


internet

eNB

RB Control

Connection Mobility Cont.

eNB Measurement

Configuration & Provision

Dynamic Resource

Allocation (Scheduler)

PDCP

PHY

MME

S-GW

S1

MAC

Inter Cell RRM

Radio Admission Control

RLC

E-UTRAN EPC

RRC

Mobility

Anchoring

EPS Bearer Control

Idle State Mobility

Handling

NAS Security

P-GW

UE IP address

allocation

Packet Filtering

Yellow boxes → logical nodes

White boxes → functional entities of the control plane

Blue boxes → radio protocol layers

• RRM: Radio Resource Management

• RB: Radio Bearer

• RRC: Radio Resource Control

• PDCP: Packet Data Convergence Protocol

• NAS: Non-Access Stratum

• EPS: Evolved Packet System

E-UTRAN & EPC functions

S1-U

S1-MME


Multiple Access


Frequency Range

UMTS FDD bands and UMTS TDD bands

Channel Bandwidth, 1Resource Block (RB) = 180KHz

1.4MHz 3MHz 5MHz 10MHz 15MHz 20MHz

6 RBs 15RBs 25RBs 50RBs 75RBs 100RBs

Modulation scheme

Downlink: QPSK, 16QAM, 64QAMUplink: QPSK, 16QAM, 64QAM (optional for handset)

Multiple AccessDownlink: OFDMAUplink: SC-FDMA

MIMO- Transmit diversity, Cyclic delay diversity (Max. 4 antenna at Base station and handset)- Spatial multiplexing, Multiuser MIMO

Peak Data rateDownlink: 150Mbps (UE category 4, 2x2 MIMO, 20MHz)

300Mbps (UE category 5, 4x4 MIMO, 20MHz)Uplink: 75Mbps (20MHz)

LTE Key Parameters


Brief Introduction of OFDMA

Each sub-carrier carries a separate low-rate stream of data

Sub-carriers

→ Orthogonal frequencies & independently modulated

Symbol duration >> channel delay spread

→ Much less ISI (Inter-Symbol Interference)

A guard time is added to each symbol

→ Cyclic Prefix in LTE

* Source: 3GPP TS25.892


Advantages & Disadvantages of OFDMA

Advantages

Scalable data rate

Simpler channel equalizer than CDMA

Robust against multipath fading by using CP

Dynamic resource allocation considering channel information

→ Maximize throughput

Disadvantages

High PAPR (Peak-to-Average Power Ratio)

Sensitive to frequency offset and clock offset

Requires guard interval

→ Reduces throughput


CDMA & OFDM vs. OFDMA

CDMA vs. OFDMA

Freq.

Time

Freq.

Time

Attribute CDMA OFDMA

Transmission bandwidth Full system bandwidth Variable up to full system bandwidth

Symbol periodVery short :

inverse of the system bandwidth

Very long :

Defined by subcarrier spacing and

independent of system bandwidth

Separation of users Orthogonal spreading codes Frequency and time

OFDM vs. OFDMA


DL/UL Multiplexing

DL Orthogonal Frequency Division Multiple Access (OFDMA)

No Inter Symbol and multipath interference

Frequency selective scheduling

Far improved MIMO performance

UL Single-Carrier FDMA (SC-FDMA)

No interference between intra cell users

Low PAPR (Peak to Average Ratio)

IDFT

S0 S1 S2 ……S10 S11

S0 S1 S2 ……S10 S11

Freq. IDFT

DFT

S0 S1 S2 ……S10 S11

Freq.

Downlink OFDMA Uplink SC-FDMA

IDFT: Invers Discrete Fourier TransformDFT: Discrete Fourier Transform


OFDMA vs. SC-FDMA

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

Brief Introduction of SC-FDMA


Frame Structure


Frame Structure Type 1: for FDD Each radio frame is 10ms long and consists of 20 slots of length

0.5ms, numbered from 0 to 19

#0 #1 #2 #3 #19

One slot, Tslot = 15360Ts = 0.5 ms

One radio frame, Tf = 307200Ts=10 ms

#18

One subframe

LTE Frame Structure

Frame Structure Type 2: for TDDSpecial fields DwPTS, GP, and UpPTS in subframe #1 (always)


Frame Structure (TDD)

Special Sub-frameDwPTS: used for downlink data transmission. (varied from three up

to twelve OFDM symbols)

GP: guard period for the downlink-to-uplink

• Guard period must cover the maximum roundtrip propagation delay within the cell

• selected by taking eNB-to-eNB interference into account

• two to ten OFDM symbols, sufficient for cell sizes up to and beyond 100 km.


Resource Grid & Cyclic Prefix

* Source : 3GPP TS 36.211

------Slot #0

One DL slot (0.5 ms) slotT

0lDL

symb1l N

RB

scU

LR

BN

N

sub

carr

iers

RB

scN

sub

carr

iers

DL RBscsymb

N NResource block

resource elements

Resource element ),( lk

0k

DL RBscRB1k N N

Slot #1 Slot #19

DL

symbN OFDM symbols

0.5 ms * 180 kHz

Configuration

No. of

subcarrie

rs / RB

No. of

symbols/

RB

Normal CP12

7

Extended CP6

24 3

kHz 15f

kHz 5.7f

RBscN

DLsymbN

kHz 15f

Configuration CP length (μs)

Normal CP5.21 (for l=0)

4.69 (for l=1,2,…,6)

Extended CP 16.67 for l=0,1,…,5

Extended CP

( )33.33 for l=0,1,2

kHz 5.7f


Asymmetric UL/DL Capacity Allocation

Single sub-frame for UL and 8times sub-frame for DL per 10ms frame

If maximally boosting UL capacity, then we can have 3 sub-frame for

UL and single sub-frame for DL per 5ms

UE is informed about UL/DL configuration via SIB-1, which is broadcast

via Broadcast Channel (BCH)

UL/DL Configuration


Special Sub-frame Configuration


10ms frame

#0 #1 #2 #3 #4 #5 #6 #7 #8 #9

Symbol :5th 6th

DCSy

stem

Ban

dw

idth

5 Reserved

31 subcarriers

31 subcarriers

Slot #0

Subframe

Primary

synchronization

signal

Secondary

synchronization

signal

5 Reserved

Slot #10

FDD

Synchronization ChannelPrimary Synchronizing Signal(PSS)

Using non-coherent detection, estimate 5msec timing and physical-

layer identity(Cell ID Group)

Channel estimation information for SSS

Secondary Synchronizing Signal(SSS)Physical-layer identity(Cell ID) is obtained

Radio-frame timing(10msec) identification


FDD

TDD

Synchronization Channel (FDD vs TDD)


Multiple Antenna Technique


Multiplexing

IDFT

S0 S1 S2 ……S10 S11

S0 S1 S2 ……S10 S11

Freq. IDFT

DFT

S0 S1 S2 ……S10 S11

Freq.

Downlink OFDMA Uplink SC-FDMA

• Performance improvement vs. WCDMA

• Simpler receiver implementation

• Larger UL cell coverage than OFDMA

IDFT: Invers Discrete Fourier TransformDFT: Discrete Fourier Transform

DL Orthogonal Frequency Division Multiple Access(OFDMA)No Inter Symbol and multipath interference

Frequency selective scheduling

Far improved MIMO performance

UL Single-Carrier FDMA(SC-FDMA)No interference between intra cell users

Low PAPR(Peak to Average Radio


DL MIMO

11h

NMh

1Nh

1Mh

Pre

cod

er

Rec

eive

r

Precoder feedback

3W

data streams

11h

NMh

1Nh

1Mh

Pre

cod

er

Rec

eive

r

data streams

CD

D

Closed-Loop MIMO Open-Loop MIMO

PMI: Precoding Matrix InformationCDD: Cyclic Delay Diversity

Supports 2X2, 4X2, 4X4 MIMOs, rank-r transmission, where r=1,2,3,4

Precoding OperationCodebook-based precoding

- Channel sensitive precoding based on UE’s PMI feedback

Large-delay CDD based Open-loop precoding

- Large delay CDD for robust communications against channel variation


Allocate the same resource blocks to Multiple UEs

→ Improves spectrum efficiency

Selection of better link antenna

(with single TX RF at the UE)

→ Improves link performance

eNodeB

UE

UE

11h

NMh

1Nh

1MhUE

eNodeB

UL MIMO

Multi-user MIMO Antenna selection diversity


LTE Feature Introduction


Scheduler supports the standardized QoS class indicators (QCIs)

QCI: QoS Class Identifier PDB: Packet Delay Budget b/w UE and PGW (Soft upper bound) (3GPP TS23.203)

PELR: Packet Error Loss Rate GBR: Guaranteed Bit Rate

QCI Resource Type Priority PDB PELR Example Services

1

GBR

2 100 ms 10-2 Conversational Voice

2 4 150 ms 10-3 Conversational Video (Live Streaming)

3 3 50 ms 10-3 Real Time Gaming

4 5 300 ms 10-6 Non-Conversational Video (Buffered Streaming)

5

Non-GBR

1 100 ms 10-6 IMS Signalling

6 6 300 ms 10-6 Video (Buffered Streaming), TCP-based (e.g., www, e-

mail, chat, ftp, p2p file sharing, progressive video, etc.)

7 7 100 ms 10-3 Voice, Video (Live Streaming), Interactive Gaming

8 8

300 ms 10-6 Video (Buffered Streaming), TCP-based (e.g., www, e-

mail, chat, ftp, p2p file sharing, progressive video, etc.)9 9

… … … … operator-specified class

Standard QoS Classes


SON Feature Overview

Rollout of the LTE leads toRapidly expanding number of Base Stations (new sites)

Parallel operation of 2G, 3G and LTE

Much higher complexity in network infrastructure and network

management (Operation & Maintenance)

Self-Organizing Network(SON) aims to configure and optimize the LTE network automatically by


UE Category

Category 1 2 3 4 5

DL 10 50 100 150 300

UL 5 25 50 50 75

Category 1 2 3 4 5

DL QPSK, 16QAM, 64QAM

UL QPSK, 16QAM QPSK, 16QAM, 64QAM

Category 1 2 3 4 5

2Rx diversity Assumed in performance requirements across all LTE UE categories

2x2 MIMO Not supported Mandatory

4x4 MIMO Not supported Mandatory

LTE UE category data rates

LTE UE category modulation formats supported

LTE UE category modulation formats supported


LTE Evolution


3GPP Work Plan for IMT-Advanced

2009 2010 20112007 2008

3GPP RAN

ITU-R WP5DProposals

Evaluation

Consensus

Specification

Work ItemStudy Item

3GPP LTE stabilized on March 2009

Schedule of study/work item for LTE-AdvancedEarly submission: Sep.2008

LTE-Advanced complete technical submission: Jun.2009

Release of Specification of LTE-Advanced: around 1Q 2011

3GPP Target of LTE-AdvancedBetter performance than IMT-Advanced requirements


Key Technologies for LTE-Advanced

Peak Data Rate improvementSupport for large bandwidths (up to 100Mhz)- Aggregation of contiguous/non-contiguous carriers)

DL MIMO enhancement - Further performance improvement for 4X4 MIMO(LTE baseline 2X2)

- 8X8 MIMO is also considered

UL SU-MIMO support- Introduce 2X4 or even 4X4 MIMO (LTE baseline 1X2)

Sector/cell throughput improvementAdvanced DL MU-MIMO with 8 Tx antenna

Multi-stream dedicated beamforming

Cell edge performance improvementRelay-coverage extension

eICIC for deployments of heterogeneous networks


eICIC

Interference coordination for non-CA based heterogeneous network (HetNet)

Time domain coordination

- Extend Rel 8/9 backhaul coordination for macro and pico deployments

Power control

- Femto eNB power reduction to avoid interference to macro UE

enhanced Inter-Cell Interference Coordination


MS

MS

MS

MS

MS

RS

BS

BS Coverage

Area

RS Coverage

Area

Relay for Coverage Extension

Reason for RelayCoverage Extension

Throughput/capacity gain

Benefits of Relay vs. Pico eNBLower cost – no fiber backhaul

Flexibility

Thank You!

chap 1. stc lte enb overview

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