휴대인터넷 (wibro) 기술old.hsn.or.kr/hsn91-06/workshop/hsn2005/document/session3/3_1.pdf ·...

Broadband IT KoreaBroadband IT KoreaEETTRI RI ©© 20042004

휴대휴대 인터넷인터넷 ((WiBroWiBro) ) 기술기술

권동승권동승, , 여건민여건민, , 유병한유병한, , 박윤옥박윤옥, , 안지환안지환

이동통신연구단이동통신연구단

- 2 - Broadband IT KoreaBroadband IT KoreaEETTRI RI ©© 20042004

이동통신연구단이동통신연구단ContentsContents

IntroductionIntroductionMarket trend, internet service evolutionMarket trend, internet service evolutionService concept of Service concept of WiBroWiBro

Service and System requirementsService and System requirements

System ArchitectureSystem Architecture

Design Principles Design Principles

Key Features of Physical LayerKey Features of Physical Layer

Key Features of MAC LayerKey Features of MAC Layer


이동통신연구단이동통신연구단Why WiBro? : Subscribers in KoreaWhy Why WiBroWiBro? : Subscribers in Korea? : Subscribers in Korea

Mobile phone/internet usersMobile phone/internet users High speed internet usersHigh speed internet users

Mobile phoneusers

MobileInternet

Unit : Million Users Unit :Million Users

23

27

16

29

3332

2931

24

15

20

25

30

35

1999 2000 2001 2002 2003

0.2

3.9

7.8

11.2

10.4

0

3

6

9

12

1999 2000 2001 2002 2003

Source : Ministry of Information & Communication (Nov, 2003)


이동통신연구단이동통신연구단Why WiBro? : Internet service evolutionWhy Why WiBroWiBro? : ? : Internet service evolution

Typical Internet Services

High-speed Wireline Internet Services (Cable Modem / ADSL / VDSL)IP service in a home domain1 ~ 10Mbps(upgraded to 50Mbps)

Medium or Low Speed Wireless Internet Services (Cdma2000, WCDMA)

Cellular-based platform : originating/termination callPublic mobile service, but expensive 144/384 Kbps (1x, wcdma), 2.4/10Mbps (Ev-DO, HSDPA)

High-speed Wireless Internet Service(IEEE 802.11 series)IP service in a local or private areaMaximum 54Mbps

Demand on a High-speed Portable Internet ServiceHigh-speed data, Low-cost, Portable(Low-mobility) Service

Easy service connectivity.Wireline and wireless network convergence.Multimedia services.


이동통신연구단이동통신연구단Why Why WiBroWiBro? : Definition? : Definition

Portable Internet Portable Internet Service(WiBroService(WiBro) is to ) is to provideaprovidea high data rate high data rate

wireless internet access with PSS(Personal Subscriber Stationwireless internet access with PSS(Personal Subscriber Station))

under the stationary or mobile environment, anytime and anywhunder the stationary or mobile environment, anytime and anywhere.ere.

DefinitionDefinition

『Portable Internet』was named as 『WiBro』. (End of April, 2004)

WiBro : Wireless BroadbandReferenceReference

WiBroWiBroWiBro

Low CostAnytime,Anywhere

MobilityHigh

Data Rate


이동통신연구단이동통신연구단Why WiBro? : Korea market wants WiBroWhy Why WiBroWiBro? : Korea market wants ? : Korea market wants WiBroWiBro

Cable Modem, ADSL, VDSL

Telephone Line Modem,

PDSN, Router / ATM

Data

Voice

Wired Line Wireless

PSTN, ISDN

Key Phone, PABX

CDMA, WCDMA

TRS

WLAN(Private)

EVDoHSDPA

High

Low

Expensive moderatePrice

DataRate

WiBro(Public)


이동통신연구단이동통신연구단Service and System RequirementsService and System Requirements

Service ClassesService ClassesRealReal--time service: time service: audio/video streaming, interactive game, ……….NonNon--realreal--time service: time service: FTP, Multimedia mail, chatting, e-commerce, …BestBest--effort Service: effort Service: Web browsing, e-mail….

RequirementsRequirementsCell types and service coverageCell types and service coverage

• Pico-cell (100 m) / Micro-cell (400 m) / Macro-cell (1km) in urban environment.

Mobility: Mobility: up to 60 km/hr.HandoffHandoff

• System shall support seamless IP-based service while users move from one cell to other.

Authentication and SecurityAuthentication and SecurityQoSQoS (Quality of Service)(Quality of Service)ChargingChargingInterworkingInterworking with other network systemswith other network systems


이동통신연구단이동통신연구단Service and System RequirementsService and System Requirements

Access Network Requirements & ParametersAccess Network Requirements & ParametersFrequency reuse factorFrequency reuse factor: FRF = 1Spectral efficiency (bps/Hz/cell):Spectral efficiency (bps/Hz/cell):

• Maximum spectral efficiency : Downlink = 6, Uplink = 2• Average spectral efficiency : Downlink = 2, Uplink = 1

Transmission data rateTransmission data rate• Minimum transmission data rate per user:

Downlink = 512 kbps, Uplink = 128 kbps• Maximum transmission data rate per user:

Downlink = 3 Mbps, Uplink = 1 MbpsHandoff requirementsHandoff requirements

• Inter-sector handoff: < 150 msec• Inter-cell handoff: < 150 msec

Average throughput (bps/Hz/cell)Average throughput (bps/Hz/cell)• Downlink = 2, Uplink = 1


이동통신연구단이동통신연구단System ArchitectureSystem Architecture

System architecture of HPi

HA

HPi-AP

HPi-AT HPi-AT

Uh

Mobile IP

PAR

FA

AAA

PAR : Packet Access RouterNMS: Network Management System

NMS(O&M)

Public IP Network

HPi-AP

PAR

W-LAN

HPi-AT

W-LAN AP

Service provider’sIP Network

Uh

Ah Ah

Ih

Ph

Ih

Interface Reference PointUh : AP-ATAh : AP-PARPh : PAR-PARIh : PAR-INTERNET

Inter AP HandoverInter PAR Handover

Seamless handover


이동통신연구단이동통신연구단System ArchitectureSystem Architecture

Service SpecificConvergence Sublayer

(CS)

MAC Common Part Sublayer(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

MAC SAP

CS SAP

MAC

PHY

Service Specific Convergence Sublayer (CS)Transformation or mapping of external network dataReceived through the CS SAP into MAC SDUs received by the MAC CPS through the MAC SAP.This includes classifying external network SDUs and associating them to the proper MAC service flow and CID. Payload header suppression. The internal format of the CS payload is unique to the CSThe MAC CPS is not required to understand the format of or parse any information from the CS payload.

The MAC CPSCore MAC functionality of system access, Bandwidth allocationConnection establishmentConnection maintenanceClassified to particular MAC connections.Quality of Service (QoS)Scheduling of data over the PHY.

Privacy SublayerProviding authenticationSecure key exchangeEncryption.


이동통신연구단이동통신연구단Design PrinciplesDesign Principles

Freq reuse factor “1” deploymentOFDMA scheme

• Multiple user signals are multiplexed by unit of subchannel in the same OFDM symbols

• Provide high granularityDiversity subchannelization based on R-S sequence

• Each cell has different R-S sequence offset.• Guarantee the number of hit is below the specific number so that the inter-

cell interference is averaged• The subchannels changing every slot give the frequency diversity effect

equivalent to frequency hopping.Low coding rate

• Provide robustness to inter-cell interference

Synchronized operationThe FA’s of the one operator and the FA’s of different operators are synchronized so that the DL and UL make no interference to each other.



Flexibly provide fast band selection and full diversity schemes in a single framework

Classify users according to channel characteristics• Band selection users and diversity users

For diversity users• Utilize multiple dimensions of diversity to enhance statistical reliability• Wideband frequency diversity and temporal diversity

For band selection users• Maximize multi-user scheduling gain at each frequency band by utilizing

channel selectivity of each user

Robust to channel and interference fluctuationHybrid-ARQ at uplink and downlink



Support the mobility of 60km/h2.35 GHz, 60 km/h → Doppler freq (fd) = 130.56 Hz

Coherence time (1/fd) = 7.66 ms• DL pilot subcarrier rotation period: 345.6 us < {0.1* Coherence time}• UL pilot subcarrier insertion period: 345.6 us < {0.1* Coherence time}

H-ARQ with short-length frame maintains the link quality

Fast access and hand-off timeShort frame length: 5msSeparate ranging time slot guarantees low latency

Flexible DL/UL Time AllocationSupportable DL/UL throughput ratio of 1:1 ~ 10:1

• DL:UL symbol ratio - 12:24(0.5:1), 18:18(1:1), 24:12(2:1), 30:6(5:1)• Apply the spectral efficiency of DL 2 bps/Hz/cell and UL 1 bps/Hz/cell

– DL/UL throughput ratio of 12:24 (12*2): (24*1) = 1:1


이동통신연구단이동통신연구단Key Features for Physical LayerKey Features for Physical Layer

Multiple Access/Duplexing: OFDMA/TDDBandwidth: 10MHz with 1k-FFT Frame length: 5 msecCell differentiation with different PN sequencesFlexible subchannelization for band selection and diversity

Full diversity subchannel by multiple symbol groupingFast AMC (adaptive modulation and coding) subchannel based on uplink CQI (channel quality indicator)Pilot tone based downlink and uplink

Modulation level: QPSK(DL/UL), 16QAM(DL/UL), 64QAM(DL only)More efficient channel coding: convolutional turbo codeH-ARQ in the downlink and uplink Separate control channel in uplink

Dedicated Ranging / Ack / CQI channel time slot



ValueSystem Bandwidth 10 MHz

Sampling frequency 10 MHz

Tone spacing 9.765625 kHz

TDD frame length 5 ms

TTG+RTG 161.6 µs

Signal bandwidth 8.447 MHz

Number of used tones 864 out of 1,024

Number of data tones 768

Basic OFDMA symbol time 102.4 µs

OFDMA symbol time 115.2 µs

Number of symbols in a frame 42

Number of pilot tones 96

Ratio of cyclic prefix time to the basic OFDM symbol time 1/8

Cyclic prefix time 12.8 µs

Key Features for Physical Layer

OFDM System parameters


이동통신연구단이동통신연구단Key Features for Physical LayerKey Features for Physical Layer5 msec frame length : 42 OFDM symbols

Flexible downlink and uplink time slot partitioning

Μ

Λ

Μ ΛΛ

Λ

Λ

Λ

Λ

Λ

Λ

Λ

Band 0

Band 1

Band 2

Band 3

Band B-2

Band B-1

Slot SlotTTG

Downlink Uplink

5 ms

RTG

Preamble Uplink Control Symbols

Safety Channel

Group Bin Tile Bin


이동통신연구단이동통신연구단Downlink PHY Frame StructureDownlink PHY Frame Structure

0 1 212 13 1424 25 2636 37 380 1 212 13 140 1 2

0 1 20 1 212 13 1424 25 26

Μ

Λ

Μ

ΛBand b-1

Band b

Band b+1

Preamble

Μ Μ

D D Λ

Λ

Λ

Λ11233547112311

11112335

Λ

D D A A A A

3 4 515 16 1727 28 2939 40 413 4 515 16 173 4 5

3 4 53 4 515 16 1727 28 29

A A ASymbol

Bin for AMC Subchannel

Bin for Safety Subchannel

Subcarrier for Diversity Subchannel

Safety Channel

Downlink Frame structure


이동통신연구단이동통신연구단Uplink PHY Frame StructureUplink PHY Frame Structure

Λ

Λ

Λ

Λ

Band 0

Band 1

Band 2

Band 3

Band B-2

Band B-1

Slot

Uplink Control Symbols

Safety Channel

Tile Bin

Tile

BinPilot

Subcarrier

Safety Subchannel

Μ Μ Μ

Uplink Frame structure



Downlink Preamble structure

• First OFDM symbols in downlink• Implicit time domain repetition (Three per OFDM symbol)

Objects• Frame timing acquisition

– Searching for maximum auto-correlation between repeating patterns in time domain

• Frequency offset estimation– Average phase rotation between sample pairs from repeating patterns

• Cell search– Cross-correlations in frequency domain– Differential demodulation to compensate frequency selective fading– Best cell search by comparing the cross-correlation magnitudes

• Symbol timing estimation– Average slope of phase rotation over all nonzero subcarriers



Band AMC Mode in Uplink and Downlink

Fast CQI report for bands from user terminals are providedPower headroom report from user terminals for uplink band selection are providedPacket scheduler in AP• Select users per band according

to channel quality at bands and scheduling criteria

• Decide appropriate modulation level and code rate for users

Downlink Band Selection



Full Diversity ModeAverage CQI report for all bands from user terminals are providedSelect appropriate modulation level and code rate in averaged C/I sense

Tones for user-A

Tones for user-B

Tones for user-C

time

freq


이동통신연구단이동통신연구단Key Features for Physical Layer

RangingObject:

• UL Synchronization• Coarse UL power control

How to transmit• BPSK with a 144 bits long sequence in frequency domain

– 1 ranging subchannel corresponds to 8 UL diversity subchannels

• Users are allowed to collide on ranging subchannels– Contention based random access with randomly selected code and ranging subchannel

• Time Domain structure Initial & HO ranging Periodic & BR ranging



4 ranging modes are defined• Initial ranging• Hand off (HO) ranging• Periodic ranging• Bandwidth request (BR) ranging• Enhanced fast HO ranging: User terminal estimates delay difference between serving

cell and target cell using preamblesRanging modes are differentiated by code and time slot

• Initialization of PN code generator depends on cell ID• Distinct code sets for each ranging mode• Initial ranging and HO ranging time slot are allocated to the first two OFDMA symbol

periods in the up-link frame• Periodic ranging and BR ranging time slot are allocated to the OFDMA symbol period

immediately following



CTC is baselineCTC (Convolutional Turbo Code) for message and traffic

• Rate 1/3 mother code for H-ARQ (Incremental redundancy)• Effective code rate: 1/12 ~ 5/6 with QPSK, 16QAM, 64QAM

– Repetition and puncturing from mother code• Large information block size up to 4800 bits

– Provides interleaving gain

Block codes for short control informationCQI/ACK : Non-binary block coding

Coded symbol scramblingFixed PN Generator with Cell ID based maskingInter-cell interference from the same frequency bin can be randomized at the encoder output



• Sub-block symbol separation, interleaving and grouping for H-ARQ support (IR scheme).

A

B

CTC Interleaver

switch

2

1Constituent

Encoder

C1

C2

CTC Encoder Interleaver

Interleaving

Symbol Selection

SymbolSelection

A'

B'

ZPuncturing

Uplink Puncturing

Subblock

AB

Subblock

Interleaver

Subblock

Subblock

Interleaver

Subblock

Subblock

Interleaver

Subblock

Subblock

Interleaver

Subblock

Subblock

Interleaver

1Y 2Y 1W 2W

H-ARQ Supportable Coding



Incremental Redundancy based H-ARQ for uplink and downlinkTo mitigate the effect of channel and interference fluctuation

• Overcome adaptation error of AMC in fading channelTo render performance improvement due to SNR gain and time diversity achieved by combing sub-packets

• Transmit different redundancy version for different sub-packet• H-ARQ provides flexibility to adapt the sub-packet transmission rate

according to the most recent channel quality feedbackMaximum number of sub-packet retransmission depends on service classes

Control for H-ARQPhysical Layer CRCSub-Packet IDARQ-Channel IDARQ-ID Sequence NumberUL-ACK/NAK ChannelDL-ACK/NAK in MAP



Uplink Control Channels-CQI, ACK, etcUL control channels

• Fast feedback on PHY link• Allocated to users, like a dedicated channel• CQI channel and ACK channel

CQI channel• DL CINR feedback

– for AMC and RRA operation– in Diversity or AMC modes

• MIMO antenna weight feedback– for Adaptive beamforming

• MIMO mode feedback – for MIMO mode and subcarrier permutation selection

ACK channel• ACK/NACK feedback for HARQ operation


이동통신연구단이동통신연구단Key Features of MAC LayerKey Features of MAC Layer

주요 기능

Resource Allocation

Packet Transmission Control

Connection Management

MAC Management

Idle Mode Operation

Handover

Security

Sleep Mode Operation

MBS (Multicast/Broadcast Service)

HARQ Supporting

Ranging Supporting

Bandwidth Request



Resource Allocation (1)DL 서브프레임 선두에서 AT에 대한 DL/UL 자원할당 정보를 표시하는 MAP 운용

DL-MAP 및 UL-MAP은 각각 하향링크 채널정보 및 상향링크 채널정보를 포함

DL은 OFDMA/TDM 방식, UL은 OFDMA/TDMA 방식으로 전송



Resource Allocation (2)MAP 사용법 및 전용 피드백 채널

Transmission InformationChannel

Downlink Frame Uplink FrameTx. Period

Every Frame

Every Frame

Every Frame

Traffic Burst Traffic/Messages Traffic/Messages -Diversity

Band AMCSafety Channel

ACKCH H-ARQ Ack - Implicit

Periodic

Remarks

FCH Frame Control Header

-

General MAP pointing

General MAP General MAP information

Channel Quality

Compact MAP pointing

Ranging Codes

Compact MAP (HARQ based)

User data burst allocation

MAP AMC support

CQICH If allocated

Ranging CH Uplink synchronization



Resource Allocation (3)MAP 구성정보

• CID (Connection ID)• DIUC/UIUC (Downlink/Uplink Interval Usage Code)• OFDMA Symbol/Subchannel Offset



Connection Management기능 및 특징

• Connection 용도 및 특징에 따른 Connection ID (CID) 관리

• CID 종류 및 용도

종류 용도 비고

Broadcast CID 방송 정보 전송

Initial Ranging CID RNG-REQ/RSP 메시지 전송 -

Basic CID 지연 민감한 메시지 전송 DL/UL 동일

Primary Management CID 상대적으로 지연 덜 민감한 메시지 전송 DL/UL 동일

Secondary Management CID IP Management 패킷 전송 DL/UL 동일

Transport CID 트래픽 데이터 전송 -

Multicast Polling CID Multicast Polling 그룹에 속한 AT가 Polling을 통한 자원할당 요청 시 사용

-

패딩 정보 전송

-

Padding CID -



Packet Transmission Control (1)Packet Classification

• IP Header에 의한 CID 매핑 기능

Packet Convergence• IP Header 압축

• Packet Suppression 및 Compression 제공– IP Header Masking 기능

– IETF ROHC 기능(옵션)



Generic MAC Header

Bandwidth Request Header

Packet Transmission Control (2)MAC Header Format

• Generic MAC Header– 트래픽 데이터 및 MAC Management

Message 전송 (DL/UL)• Bandwidth Request Header

– 자원 할당 요청 용 (UL)• Fragmentation Sub-header

– MAC CPS SDU 분할 전송 용 (DL/UL)• Packing Sub-header

– MAC CPS SDU 연접 전송 용 (DL/UL)• Grant Management Sub-header

– Piggybacking 자원 할당 요청 용 (UL)

전송 방식

• Fragmentation– SDU를 분할하여 해당 분할을 하나의 PDU

로 전송

• Packing– 여러 SDU를 연접하여 하나의 PDU로 전송

• Piggybacking– Sub-header를 사용하여 하나의 PDU에

Piggybacking 하여 전송



Packet Transmission Control (3)ARQ

• 다양한 ACK 피드백 방식

– Cumulative ACK– Selective ACK– Cumulative-Selective ACK– Sequential ACK

• 타이머 기반의 재전송 메커니즘

– ARQ Block Lifetime– ARQ Retry Lifetime– Tx/Rx Window Purge Time

• 전용 피드백 채널 운용

– Dedicated ACK Channel – Dedicated CQI Channel

• Flow Control 기능

– SDU Discard– Tx/Rx Window Change

Not-sent OutstandingTransmit Waiting-for-

retransmission

Done

ARQ_RETRY_TIMEOUTor NACK

Retransmit

Discarded

ARQ

_BLO

CK_LIF

ETIM

E

ARQ

_BLO

CK_LIF

ETIM

E

ACKA

CK

ACK

ARQ 메커니즘



MAC Management운용 방식

• MAC Management를 위한 메시지 정의

• 메시지에 대응되는 CID 매핑

• Generic MAC Header로 전송

메시지 종류

기능 관련 메시지 비고

Cell Sync. DCD, UCD, RNG-REQ/RSP

Resource Allocation DL-MAP, UL-MAP -

Registration REG-REQ/RSP, DREG-REQ/CMD -

Authorization PKM-REQ/RSP -

Connection Management DSx-REQ/RSP/ACK/RVD DSA, DSC, DSD

ARQ ARQ-Feedback/Discard/Reset -

AAS Service AAS-FBCK-REQ/RSP, AAS-BEAM-SLT/REQ/RSP -

AT Capability Negotiation SBC-REQ/RSP -

Burst Profile Change DBPC-REQ/RSP -

Channel Measurement REP-REQ/RSP

NBR-ADV, HO-REQ/RSP, SCN-REQ/RSP/REPORT

-

Handover -



Idle Mode (1)개념

• AT가 여러 AP에 의해서 관장되는 영역을 돌아다니면서 특정한 AP에 등록되지 않고도 주기적으로 DL Broadcast 메시지를 받을 수 있도록 하기 위한 것

• Idle Mode에 있는 AT는 Handover 또는 Normal Operation에 따르는 Active Requirement를 지키지 않아도 됨

• 특정 구간에서만 AT 자신이 호출되었는지를 체크하면서 Power Saving 운용을 할 수 있음

AT 상태

• 모든 Active Connection 단절

• Serving AT에게 모든 Management CID 및 IP Address 반환

• Connection 설정 절차 없이 MBS 서비스 받을 수 있음

Idle Mode 진입 절차

• AP가 DREG-CMD 전송(unsolicited)• AT가 DREG_REQ 전송 후 AP가 AP가 DREG-CMD 전송



Idle Mode (2)기능 및 단계

• Idle Mode Initiation• Cell Selection• Broadcast Paging Message Time Synchronization• Paging Unavaible Interval • Paging Listening Interval• Paging Interval• Broadcast Paging Message• Paging Availability Mode Termination

Paging Unavailble Interval

Scanning & Sync

Paging Interval

Paging Listening Interval



Handover (1)주요 특징 및 기능

• Neighbor AP Advertisement 방송정보 송신

• Scanning 절차– AT에 의해서 Target AP로 타당한지를 결정하기 위해서 Neighbor AP를 탐색하

는 절차

• Soft HO (SHO) 및 Fast BS Selection (FBSS) 지원– Anchor BS/Active BS 개념 도입

– Fast Anchor BS Selection Feedback Channel 사용

• AT-initiated & AP-initiated HO 지원

• HO Drop Situation 복구 기능 지원

HO 관련 MAC Management message• NBR-ADV• SCN-REQ/RSP/REPORT• HO-REQ/RSP• RNG-REQ/RSP• SBC-REQ/RSP• PKM-REQ/RSP• REG-REQ/RSP



Handover (2)Scanning & HO Initiation

AP-initiated HOAT-initiated HO



Handover (3)HO Process

AP 1 AP 2

AT AT

4. Cell Reselection

Inter-Sector HO (AT-initiated) Inter-AP HO (AT-initiated)



Handover (4)Soft Handover (SHO)

• DL에서 둘 이상의 AP가 동시에 해당 AT로 동일한 MAC PDU를 전송

• UL에서 둘 이상의 AP가 해당 AT로부터 동시에 수신(demodulation/decoding) Fast Base Station Selection (FBSS)

• 링크 품질을 향상시키기 위하여 Selection Diversity와 Switching Mechanism을 활용하는 것

• AT는 주어진 프레임에서 특정한 AP(Anchor AP)와만 데이터를 주고 받음

• Anchor AP는 매 프레임 단위로 변경될 수도 있음

Anchor AP-Anchor AP는 MSS에 대한 자원을 할당하여야 하는 책임을 가지는 AP

-Basic CID, Primary Mgt CID, Secondary Mgt CID, & Transport CID 할당의

책임-AT는 항상 Anchor BS와 동기를 유지하여야 함

-Anchor BS하고만 Ranging을 수행하여야 함-AT는 DL 제어 정보(DL-MAP, UL-MAP, FCH, DL Broadcast message)를 수신하기위하여 Anchor AT를 모니터링 함

Active AP-FBSS/SHO 절차에만 적용-Active Set은 해당 AT에 대한 Active AP들의 목록을 포함-Active BS는 해당 AT의 MAC Information에 대한 정보(capability, security parameters, service flows)를 제공 받음-SHO 모드에서 AT는 모든 Active AP들과 데이터를 송수신

Anchor AP-Anchor AP는 MSS에 대한 자원을 할당하여야 하는 책임을 가지는 AP

-Basic CID, Primary Mgt CID, Secondary Mgt CID, & Transport CID 할당의

책임-AT는 항상 Anchor BS와 동기를 유지하여야 함

-Anchor BS하고만 Ranging을 수행하여야 함-AT는 DL 제어 정보(DL-MAP, UL-MAP, FCH, DL Broadcast message)를 수신하기위하여 Anchor AT를 모니터링 함

Active AP-FBSS/SHO 절차에만 적용-Active Set은 해당 AT에 대한 Active AP들의 목록을 포함-Active BS는 해당 AT의 MAC Information에 대한 정보(capability, security parameters, service flows)를 제공 받음-SHO 모드에서 AT는 모든 Active AP들과 데이터를 송수신



Security (1)Authorization Policy Support

• RSA• EAP• Mutual/Unidirectional Authorization• OMAC/HMAC

PKM Version Support• PKM version1 (RSA-based PKM)• PKM version2 (EAP-based PKM)

RSA-based PKM 및 EAP-based PKM 비교

• Authorization 방식 및 AK key 분배 메시지가 다름

– RSA-based PKM의 경우 Authentication Information/Authorization Request/ Authorization Reply 메시지를 통하여 Authorization을 처리하고 AP에서 AK키 분배

– EAP-based PKM의 경우 EAP-Transfer 메시지를 통해 Authorization을 하고 AAA 서버에서 AK키를 관여하여 분배

• AK Key 분배 Attribute 동일

– AK Key, Sequence Number, Lifetime • TEK Key 요청 및 분배 처리 동일



Security (2)절차

AT AP PARSBC-REQ (Authorization Policy Negotiation)

EAP-TLS User Authentication and AK Distribution base on EAP-TLS

PKM-RSP/key reply(TEK key, sequence number, IV)

PKM-REQ/EAP-transfer (EAP Payload) ADTcmd

(additional information, EAP Payload)

AAA

Diameter(EAP-TLS)

Diameter(EAP-TLS)

ADTcmd(additional information, EAP Payload)PKM-RSP/EAP-transfer

(EAP Payload)

PKM-REQ/key request

...

SBC-RSP

PKM-REQ/Authentication InformationRegacy PKM

PKM-REQ/Authorization Request

PKM-RSP/Authorization Reply

PKMv2-EAP

PKM-REQ/RSP Messages (for PKM v2)

-EAP Transfer message-EAP Keying message-Pre-Authentication message-Mutual-Authentication message

PKM-REQ/RSP Messages (for PKM v2)

-EAP Transfer message-EAP Keying message-Pre-Authentication message-Mutual-Authentication message



HARQ SupportingHARQ용 Compact MAP을 사용하여 해당 AT에 자원 할당

UL Burst #1

UL Burst #2

UL Burst #3

Compact MAP 1

Compact MAP 2

DL Burst #5

DL Burst #6

DL Burst#7

General M

AP

DL Burst #1

DL Burst #2

DL Burst #3

DL Burst #4

FCH

MAP IE

Basic CID, Nep/Nsch for AT #ABasic CID, Nep/Nsch for AT #B

Basic CID, Nep/Nsch for AT #D

Compact MAP 3

CQI CH

ACK CH

Ranging Subchannel

MAP IEMAP IE

MAP IE

Basic CID, Nep/Nsch for AT #C

MAP IE

: HARQ_Pointer_IE



Ranging Supporting (1)Ranging 방식 비교

메시징 방식 CDMA 방식

Unicast-polling × Unicast-polling ×

Contention-based × Contention-based Ο2

Contention-based × Contention-based

Periodic RangingUnicast-polling ∆ Unicast-polling ×

Ο1

Initial Ranging

×: 불가능, Ο: 가능(채택), ∆: 불가능하지는 않으나, 효율성 및 구현 측면에서 채택하지 않음Ο1: CDMA-based Ranging (status = success인 RNG-RSP 수신) 후,

CDMA_Allocation_IE에 할당된 UL 구간으로 RNG-REQ (with MAC Address) 메시지 전송

Ο2: CDMA-based Ranging 절차만 계속 (status = success가 될 때까지)



Ranging Supporting (2)Initial Ranging 절차

AP

AT

1) DL Sync2) UL Burst 정보획득

AT

AP AP

AT

AP

AT

6) Backoff 7) Ranging Code 전송

AP

AT

UL-MAP

AP

AT

UL-MAP

RNG-REQ(MAC_Address)

8) Timing, Power, & Frequency Adjustment9) Random Subch, Symbol, Code 선택10) Ranging Code 전송

DCD/UCD/DL-MAP

3) UL-MAP Scan 4) Random Subch, Symbol, Code 선택5) Ranging Code 전송

RNG-REQ (Code)

RNG-RSP(Success)

AT

AP

AT

AP AP

AT

RNG-RSP(Management CIDs)

RNG-REQ (Code)

Binary-exponential

Random Backoff

11) RNG-RSP (Success) 수신mapped with transmitted Subch, Symbol, & Code

12) RNG-REQ message 전송with MAC Address

13) RNG-RSP (Management CIDs) 수신

Timer T3 Expire

RNG-REQ (Code)

RNG-RSP(Continue)



Ranging Supporting (3)Periodic Ranging 절차



Bandwidth Request (1)BW Request 제공 방식

제공 방식 기능 요청 방식

Unicast Polling UL-MAP 지정에 의해 특정 AT에 할당된 UL 자원상으로 BW Request Header 전송

Piggybacking동일한 CID에 대한 BW Request 할당 요청의 경우, UL 데이터전송을 위한 자원이 가용할 때, Grant Management Subheader를 추가하여 전송

Incremental

BW Stealing Data 전송용으로 할당된 자원을 AT의 판단에 따라 BW Request Header를 전송하기 위한 목적으로 전용하여 사용

Aggregate/ Incremental

BW Request용 CDMA Code를 Ranging Domain (UIUC = 11)에서 전송/성공 후, AP에 의하여 할당되는 UL-MAP의CDMA_Allocation_IE에 의하여 주어지는 UL 자원을 사용하여BW Request Header 전송


CDMA-based Request


CDMA-based Request는 Ranging (Random Access) 및 UL 자원 할당의 두 단계를 가진다.



Bandwidth Request (2)CDMA-based BW Request 절차



MBS (1)MBS

• 여러 개의 AP들에 의한 Synchronized Transmission을 통하여 별도의Network Entry 절차를 거치지 않고도 다수의 AP에 걸쳐 끊임없는Multicast/Broadcast Service 제공

MBS Zone • 하나의 MBS Service Flow에 대하여 CID 및 SA가 유효한 영역

• 하나의 AP는 여러 개의 MBS Zone에 대응 될 수 있음

MBS Security Association• MBS Group Security Association (MBS GSA)는 AP에서 제공

• MBS GSA 정보– Cryptographic Suite– Key Material

» MBS Authorization Key (MAK), » MBS Group Traffic Encryption Key (MGTEK)

– LifetimeMBS Traffic Encryption

• AES CTR Mode 사용

• PDU는 MBS Traffic Key (MTK)를 사용하여 Encryption함

• MTK는 MAK 및 MGTEK를 사용하여 생성



MBS (2)MBS MAC PDU Ciphertext Payload Format

MBS-MAP• AP는 해당 MBS Zone에서 서비스되는 MBS Connection들을 기술하기 위하여 MBS-

MAP message 전송

• MBS Burst 할당 정보 포함

CID Use• 특정한 영역에 있는 Dedicated Multicast CID들 사용

• 동일한 MBS_Zone에 속하는 AP들은 동일한 CID를 사용

• CID 할당은 MBS Content Server가 관리

Macro-diversity Gain:• MBS_Zone 내의 인접한 AP들에서 동일한 데이터 (PDU Header, Payload; 동일한

Channel Coding, Modulation 및 변조방식 사용)를 동일한 심볼구간 및 Carrier로 전송하여 Diversity Gain 획득



MBS (3)Register

• 특정 셀에 등록되지 않은 채로 Idle Mode 및 Sleep Mode에서 MBS service 유지 가능

SA Capability• MBS용 GSA (MBS-GSA)와 매핑

Data Encryption• Application Layer 및 MAC Layer에서의 Data Encryption 둘 다 지원

• MAC Encryption은 AES-CTR Mode 만 사용 가능

Power Saving Operation• MBS-MAP을 사용하여 MBS Burst들에 적용될 Physical Attributes 뿐만 아니

라 각각의 Connection에 대한 다음에 전송될 프레임 및 그 프레임에서의 위치에 대한 정보도 제공

• Scheduling을 통하여 Power Saving을 극대화 할 수 있음



감사합니다감사합니다..

Thank You for Listening!!!Thank You for Listening!!!

FourthGeneration

휴대인터넷 (wibro) 기술old.hsn.or.kr/hsn91-06/workshop/hsn2005/document/session3/3_1.pdf ·...

Documents