WiMAX/LTE-A : 4G Wireless Broadband Networks

1

中山大學 電機系 許蒼嶺教授

行動通信標準演進

3

Evolution of Wireless Access Technologies

4

802.11n(smart antennas)802.11Mesh extns.

Loca

l Are

aF

ixed

Wid

e A

rea

Mob

ile

Cov

erag

e/M

obili

ty

Met

ro A

rea

Nom

adic

802.16(Fixed LOS)

802.16a/d(Fixed NLOS)

802.11b/a/g

Mobile Industry

Fixed Wireless Industry

4G Air Interfaces

Data Rates (kbps)100,000 +

3GPP2CDMA

2000-1X

HRPDA1x

EVDO

1x EVDV Rel. C

1x EVDVRel. D

GSM UMTS HSPAGPRS EDGE LTE 3GPP

MOBILE BROADBAND

DSL ExperienceDial Up

Higher Data Rate / Lower Cost per Bit

802.16e(Mobile WIMAX)

WiMAX vs 3GPP 發展時程

5

3GPP Radio Access Milestones

Operator’s Service Stack

8

IMSLayer

Application services

Mobility, Policy and Administration Services

EPC

Core network

Access technologiesconnection gateways

Access Technologies

WiMAXLTEDSLAM WiFi

Devices

WiMAX Market Position

9

Mobile(GSM / GPRS / 3G /HSPA /LTE)

Mobile(GSM / GPRS / 3G /HSPA /LTE)

xDSL / FTTx

xDSL / FTTx

現有無線接取技術比較

10

Technical Winner

MarketWinner =

?

11

WiMAX 市場現況

12

Source : Ovum 2008/12

Population penetration of mobile, fixed and broadband across Asia-Pacific

WiMAX Markets in Developed Country

13

Fix and Nomadic broadband access Broadband Penetration > 50%Broadband Infrastructure is Developed vs. xDSL / FTTx

No Significant Technical advantage except Nomadic

Incumbent Operator cost advantage High Initial CAPX needed

Niche Market Rural : Low ARPU Bundle Service

Triple play Killer Application ?

WiMAX is Still Looking for

Business Model

WiMAX Markets in Emerging Country

14

Fix and Nomadic broadband access Broadband Penetration < 5%Broadband Infrastructure is Low vs. xDSL / FTTx

Significant CAPX advantage Significant Deploying time advantage

Demand Growing

WiMAX Opportunity ?

Markets in Emerging Country

15

越南，胡志明市具備 WiMAX市場機會但卻選擇3GPP 陣營

台灣 WiMAX 產業鏈

16

17

Source : 工研院 IEK 2010/3

18

TOP5 WiMAX Vendors Strategy

Source: Ovum 2009/9

An Industry War

19

3GPP 是市場主流

20

21

IEEE std 802.16

22

Standard Roadmap IEEE 802.16 - 2001 IEEE 802.16a/b/c - 2003

Amendments to 802.16-2001 IEEE 802.16 - 2004

Compatibility issue with HIPERMAN of ETSI 802.16d project Replace previous standards Fixed site access

IEEE 802.16e, 16f - 2005 (amendment) Extend to mobility MIB

IEEE 802.16g-2007(amendment) Management Plane Procedures and Services

IEEE 802.16j – 2008 IEEE 802.16m – 2011 (4G)

23

Features Broad Bandwidth

Up to 134.4Mbit/s Transit over 50KM

Typical Architecture 1 BS + n SSs PMP or MESH

Spectrums From 2 to 66 GHz NLOS and LOS

Duplexing Techniques TDD or FDD

WiMAX Forum Conformance and Interoperability

24

Scope of Standard

PHY SAP

MAC SAP

CS SAP

Service-SpecificConvergence Sublayer

( MAC CS )

Common Part Sublayer ( MAC CPS )

Security Sublayer( MAC SS )

Physical Layer(PHY)

MA

CP

HY

Scheduliing ServicesQoS ParametersBandwidth Allocation

25

TDMA/OFDM/OFDMA

DIUC=Downlink Interval Usage CodeUIUC=Uplink Interval Usage Code

38

IEEE 802.16j-2008

One MR-BS (Multi-hop Relay - Base Station) and many RS (Relay Station)

Transparent mode Only data are relayed via RS Remove obstruction

Non-Transparent mode Expand service coverage Both signaling and data are relayed via RS Increase utilization/throughput

IEEE 802.16j WiMAX

39

IEEE 802.16j Configuration

40

Transparent RS

41

Non-Transparent RS

42

43

OFDMA Symbol and Transparent RS Frame

44

OFDMA Symbol and Non-Transparent RS Frame

IEEE 802.16j Multi-hopTopology

45

46

IEEE 802.16j Independent Scheduling Zones

47

Bandwidth Request: Store-and-Forward Mode

48

Bandwidth Request: End-to-End Mode

Centralized vs Distributed Scheduling

Centralized Scheduling For small size of networks Only BS to do bandwidth allocations

Distributed Scheduling For networks with hops greater than 2 Both RS and BS do bandwidth allocations

49

50

Centralized Scheduling

51

Distributed Scheduling

52

Modules for Distributed Scheduling in BS/RS

53

Classification & Addressing

SSBSUplink

Downlink

SFIDSFID

SFIDSFID

SFID : Service Flow Identifier (32 bits)

CID : Connection Identifier (16 bits)

54

Scheduling Services

Priority 802.16-2004

ServiceType

802.16e-2005

ServiceType

Typical Appcations

1st UGS UGS T1/E1 transport

VoIP without silence suppression

2nd ertPS ERT-VR VoIP with silence suppression

3rd rtPS RT-VR MPEG Video

4th nrtPS NRT-VR FTP with guaranteed minimum throughput

5th BE BE HTTP

55

QoS ParamSetUGS ：Maximum LatencyTolerated JitterUplink Grant Scheduling TypeRequest/Transmission Policy

ERT-VR ：Maximum LatencyUplink Grant Scheduling TypeRequest/Transmission Policy

RT-VR ：Maximum Sustained Traffic RateMinimum Reserved Traffic RateMaximum LatencyUplink Grant Scheduling TypeRequest/Transmission Policy

NRT-VR ：Minimum Reserved Traffic RateUplink Grant Scheduling TypeRequest/Transmission Policy

BE ：Lowest traffic PriorityRequest/Transmission Policy

QoSParamSet

56

Bandwidth Allocation

Uplink Packet Scheduler(802.16 Frame Maker)

CIDs &QoS-ParamSets

INPUT OUTPUT

UL-MAP

UL-MAP :Uplink Map

57

Summary of MACand the undefined part of IEEE 802.16

INPUT

OUTPUT

58

Modulations & Channel Size

Access Range:QPSK > QAM-16 > QAM-64

Data Rate:QAM-64 > QAM-16 > QPSK

US

European

Uplink Mandarory

Downlink Mandarory

59

Frame Durationswith TDD Frame Structure

0.5/1/2 ms

60

Number of PS in 16-QAM

Frame duration = 1 ms Signal (Baud) rate = 16 Mbauds/sec 4 bits in a signal (baud) using 16-QAM Ts=LT, Data rate, R = LS = 4 x16 = 64 Mbps Number of PS (Physical Slot) (64 Mbps x 1 ms) / 16 bits = 4000 Assume every PS = 16 bits

4G: IEEE 802.16m and LTE-A

ITU-R’s IMT-Advanced (4G) requirements up to 1 Gbps in static or low mobility environment up to 100 Mbps in high-speed mobile environment

Multicarrier is the technology to utilize wider bandwidth for parallel data transmission across multiple RF carriers. IEEE 802.16m LTE-A

Carrier Aggregation (CA) Component Carrier (CC)

IEEE WiMAX Frame Structure

Basic WiMAX Frame Structure

1. Type-1 AAI subframe that consists of 6 OFDMA symbols.

2. Type-2 AAI subframe that consists of 7 OFDMA symbols.

3. Type-3 AAI subframe that consists of 5 OFDMA symbols.

4. Type-4 AAI subframe that consists of 9 OFDMA symbols. This type shall be applied only to an UL AAI subframe for the 8.75 MHz channel bandwidth when supporting the WirelessMANOFDMA frames.

802.16e V.S. 802.16m802.16e 802.16m

Bandwidth(MHz) 10 10

Sampling frequency(MHz) 11.2 11.2

FFT size 1024 1024

Sub-carrier frequency spacing(kHz) 10.94 10.94Frame duration(ms) 5 5

Useful symbol time(us) 91.4 91.4

Guard time(us) 11.4 11.4

OFDMA symbols 48 48

OFDMA symbol duration(us) 102.9 102.9

Number of used sub-carriers 841(840) 865

Number of guard sub-carriers 183(184) 159

Number of pilot sub-carriers 120 120

Number of data sub-carrier 720 745

Data rate for QPSK(Mbps) 13.82 14.30

Data rate for 16QAM(Mbps) 27.65 28.61

Data rate for 64QAM(Mbps) 41.47 42.91

IEEE 802.16m OFDMA Parameters

67

Nominal Channel Bandwidth (MHz) 5 7 8.75 10 20

Over-sampling Factor 28/25 8/7 8/7 28/25 28/25

Sampling Frequency (MHz) 5.6 8 10 11.2 22.4

FFT Size 512 1024 1024 1024 2048

Sub-Carrier Spacing (kHz) 10.937500 7.812500 9.765625 10.937500 10.937500

Useful Symbol Time Tu (μs) 91.429 128 102.4 91.429 91.429

Cyclic Prefix (CP) Tg=1/8 Tu

Symbol Time Ts (μs)102.857

144 115.2 102.857 102.857

FDD

No. of OFDM symbols per Frame

48 34 43 48 48

Idle time (μs) 62.857 104 46.40 62.857 62.857

TDD

No. of OFDM symbols per Frame

47 33 42 47 47

TTG + RTG (μs) 165.714 248 161.6 165.714 165.714

Cyclic Prefix (CP) Tg=1/16 Tu

Symbol Time Ts(μs) 97.143 136 108.8 97.143 97.143

FDD

No. of OFDM symbols per Frame

51 36 45 51 51

Idle time (μs) 45.71 104 104 45.71 45.71

TDD

No. of OFDM symbols per Frame

50 35 44 50 50

TTG + RTG (μs) 142.853 240 212.8 142.853 142.853

Number of used subcarriers 433 865 865 865 1729

802.16m Guard Bands

Baud Rate

B: baud rate, number of symbols in one secondS: number of symbols in an OFDMA Sub-frameT: OFDMA Sub-frame durationN: number of sub-carriers in an OFDMA frame B = ( ) x N

ST1

Data Rate/Bit Rate

R: data rate (bps)M: number of different signal elements in MCSB: baud rate, number of symbols in one second

R = B x

2(log )M

Frame time = 5 msec , Number of carriers = 192Data Rate = (360/5 msec)x192= 13.824 Mbps

LTE-A

Enhanced Multicast Broadcast Service (EMBS)

LTE-A Frame Structure

0 1 2 3 18 19……

One radio frame, Tframe=10ms

Tslot=0.5ms

……

…

Resource Block (RB)

Resource Element (RE)

Tsub-frame=1ms

Sub-

carr

iers

…

OFDM/SC-FDMA Symbols symbN

Sub-

carr

iers

RBSCN

RBSCN

Resource Block (RB)

One OFDMA frame (10 msec) = 10 sub-framesOne sub-frame (1 msec) = 2 slotsOne slot (0.5 msec) = 7 symbols Symbol rate = 7/0.5 msec = 14000 symbols/sec One RE = One symbol x one sub-carrier One RB = 7 symbols x N sun-carriers

Assume total BW = 30 Mhz and 64-QAMOne sub-carrier = 15 KhzTotal sub-carriers = 30 MHz/15 Khz = 2000 sub-carriersTotal capacity (Data rate) = 2000 x 14000 symbols x 6 bits/symbols= 168 Mbps

Systematic bits

Turbo coding 1/3

Mapping to the circular buffer

Systematic bits Parity bits

Systematic bits Parity bits

Channel Coding

不同重傳次數的 HARQ 封包

76

Systematic bits Parity bits

RV=0 RV=1 RV=2 RV=3

1st transmission

2nd transmission

3rd transmission

4th transmission

Coding rate=3/4

BSMN

BS’s HARQ buffer

ERROR

NACKACKsuccess

MN’s HARQ buffer

ERROR

+

||

1st transmission

2nd transmission

3rd transmission

4th transmission

HARQ 在 Uplink 的運作流程

LTE-A: E-MBS Deployment with Broadcast Only and Mixed Carrier

LTE-A: Carrier Types From the perspective of an advanced MS

(AMS) Primary carriers

exchanges traffic and control signals with an advanced BS (ABS)

mobility, state, and context Secondary carriers

An ABS can additionally assign secondary carrier(s) to an AMS

Controlled by the ABS through the primary carrier

LTE-A: Carrier Types From the perspective of an ABS

Fully configured carrier carrying all control channels synchronization, broadcast, multicast, and unicast

control channels both single-carrier and multicarrier AMSs can be

served Partially configured carrier

primarily to support downlink only transmission only for frequency-division duplex (FDD) deployment a dedicated EMBS carrier is one example

Multicarrier Frame Structure(LTE-A and WiMAX 802.16m)

An example of multicarrier frame structure with legacy support.

Multicarrier Transceiver Architectures (LTE-A and WiMAX 802.16m)

Basic concept of subcarrier alignment.

802.16m Multicarrier Operation with Usage of The Guard Bands

Multicarrier Transceiver Architectures (LTE-A)

Different types of AMS transceiver architecture for multicarrier aggregation.

Network Entry (LTE-A)

Network entry procedure for multicarrier support.

AAI: Advanced Air Interface

Activation and Deactivation ofAssigned Carriers (LTE-A)

Multilevel carrier management scheme.

Handover (LTE-A)

Relay Related Connections

Fractional Frequency Reuse (FFR) for Directional Antenna

CA Scenarios and Component Carrier (CC) Types (LTE-A)

Example of carrier aggregation scenarios: a) contiguous aggregation of five component carriers with equal

bandwidth b) non-contiguous aggregation of component carriers with

different bandwidths

Primary and Secondary CCs (LTE-A)

UE served bPCell/SCell configuration for different y the same eNB

References1. I.-K. Fu et al., “Multicarrier Technology for 4G WiMax System,” IEEE

Communications Magazine, Vol. 48 , Issue 8, Page(s): 50–58, Aug. 2010.

2. S. Ahmadi, “An Overview of Mext-Generation Mobile WiMAX Technology,” IEEE Communications Magazine, Vol. 47 , Issue 6, Page(s): 84–98, Jun. 2009.

3. O. Oyman, J. Foerster, Y.-J. Tcha, and S.-C. Lee, “Toward enhanced mobile video services over WiMAX and LTE,” IEEE Communications Magazine, Vol. 48 , Issue 8, Page(s): 68-76, Aug. 2010.

4. K.I. Pedersen et al., “Carrier Aggregation for LTE-Advanced: Functionality and Performance Aspects,” IEEE Communications Magazine, Vol. 49 , Issue 6, Page(s): 89-95, Jun. 2011.

5. M. Iwamura et al., “Carrier Aggregation Framework in 3GPP LTE-Advanced,” IEEE Communications Magazine, Vol. 48 , Issue 8, Page(s): 60-67, Aug. 2010.