Overview of Portable Internet Technology

Transcription

1 Broadband IT Korea 휴대인터넷 (WiBro) 기술 권동승, 여건민, 유병한, 박윤옥, 안지환

2 -2- Broadband IT Korea Contents Introduction Market trend, internet service evolution Service concept of WiBro Service and System requirements System Architecture Design Principles Key Features of Physical Layer Key Features of MAC Layer

3 -3- Broadband IT Korea Why WiBro?? : Subscribers in Korea Mobile phone/internet users High speed internet users Unit : Million Users Mobile phone users Unit :Million Users Mobile 6 20 Internet Source : Ministry of Information & Communication (Nov, 2003)

4 -4- Broadband IT Korea Why WiBro?? : Internet service evolution Typical Internet Services High-speed Wireline Internet Services (Cable Modem / ADSL / VDSL) IP service in a home domain 1 ~ 10Mbps(upgraded to 50Mbps) Medium or Low Speed Wireless Internet Services (Cdma2000, WCDMA) Cellular-based platform : originating/termination call Public mobile service, but expensive 144/384 Kbps (1x, wcdma), 2.4/10Mbps (Ev-DO, HSDPA) High-speed Wireless Internet Service(IEEE series) IP service in a local or private area Maximum 54Mbps Demand on a High-speed Portable Internet Service High-speed data, Low-cost, Portable(Low-mobility) Service Easy service connectivity. Wireline and wireless network convergence. Multimedia services.

5 -5- Broadband IT Korea Why WiBro?? : Definition Definition Portable Internet Service(WiBro) ) is to providea high data rate wireless internet access with PSS(Personal Subscriber Station) under the stationary or mobile environment, anytime and anywhere. Reference Portable Internet was named as WiBro. (End of April, 2004) WiBro : Wireless Broadband Mobility High Data Rate WiBro Low Cost Anytime, Anywhere

6 -6- Broadband IT Korea Why WiBro?? : Korea market wants WiBro High WLAN (Private) WiBro Data Rate EVDo (Public) Cable Modem, ADSL, HSDPA Data VDSL Telephone Line Modem, PDSN, Router / ATM Low Expensive Price moderate Voice PSTN, ISDN CDMA, WCDMA Key Phone, PABX TRS Wired Line Wireless

7 -7- Broadband IT Korea Service and System Requirements Service Classes Real-time service: audio/video streaming, interactive game,. Non-real real-time service: FTP, Multimedia mail, chatting, e-commerce, Best-effort effort Service: Web browsing, . Requirements Cell types and service coverage Pico-cell (100 m) / Micro-cell (400 m) / Macro-cell (1km) in urban environment. Mobility: up to 60 km/hr. Handoff System shall support seamless IP-based service while users move from one cell to other. Authentication and Security QoS (Quality of Service) Charging Interworking with other network systems

8 -8- Broadband IT Korea Service and System Requirements Access Network Requirements & Parameters Frequency reuse factor: FRF = 1 Spectral efficiency (bps/hz/cell): Maximum spectral efficiency : Downlink = 6, Uplink = 2 Average spectral efficiency : Downlink = 2, Uplink = 1 Transmission 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 Mbps Handoff 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

9 -9- Broadband IT Korea System Architecture System architecture of HPi Public IP Network AAA Service provider s IP Network HA FA I h I h NMS(O&M) W-LAN AP W-LAN HPi-AP U h PAR A h P h Mobile IP PAR A h U h HPi-AP PAR : Packet Access Router NMS: Network Management System Interface Reference Point U h : AP-AT A h : AP-PAR P h : PAR-PAR I h : PAR-INTERNET HPi-AT HPi-AT HPi-AT Seamless handover Inter AP Handover Inter PAR Handover

10 System Architecture MAC PHY CS SAP Service Specific Convergence Sublayer (CS) MAC SAP MAC Common Part Sublayer (MAC CPS) Privacy Sublayer PHY SAP Physical Layer (PHY) Service Specific Convergence Sublayer (CS) Transformation or mapping of external network data Received 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 CS The MAC CPS is not required to understand the format of or parse any information from the CS payload. The MAC CPS Core MAC functionality of system access, Bandwidth allocation Connection establishment Connection maintenance Classified to particular MAC connections. Quality of Service (QoS) Scheduling of data over the PHY. Privacy Sublayer Providing authentication Secure key exchange Encryption Broadband IT Korea

11 -11- Broadband IT Korea Design Principles Freq reuse factor 1 deployment OFDMA scheme Multiple user signals are multiplexed by unit of subchannel in the same OFDM symbols Provide high granularity Diversity 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 intercell 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 operation The 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.

12 -12- Broadband IT Korea Design Principles 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 fluctuation Hybrid-ARQ at uplink and downlink

13 -13- Broadband IT Korea Design Principles Support the mobility of 60km/h 2.35 GHz, 60 km/h Doppler freq (fd) = Hz Coherence time (1/fd) = 7.66 ms DL pilot subcarrier rotation period: us < {0.1* Coherence time} UL pilot subcarrier insertion period: us < {0.1* Coherence time} H-ARQ with short-length frame maintains the link quality Fast access and hand-off time Short frame length: 5ms Separate ranging time slot guarantees low latency Flexible DL/UL Time Allocation Supportable 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

14 -14- Broadband IT Korea Key Features for Physical Layer Multiple Access/Duplexing: OFDMA/TDD Bandwidth: 10MHz with 1k-FFT Frame length: 5 msec Cell differentiation with different PN sequences Flexible subchannelization for band selection and diversity Full diversity subchannel by multiple symbol grouping Fast 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 code H-ARQ in the downlink and uplink Separate control channel in uplink Dedicated Ranging / Ack / CQI channel time slot

15 -15- Broadband IT Korea Key Features for Physical Layer OFDM System parameters System Bandwidth Sampling frequency Value 10 MHz 10 MHz Number of used tones 864 out of 1,024 Number of data tones 768 Number of pilot tones 96 Tone spacing Signal bandwidth khz MHz Ratio of cyclic prefix time to the basic OFDM symbol time 1/8 Basic OFDMA symbol time µs Cyclic prefix time 12.8 µs OFDMA symbol time µs TDD frame length 5 ms Number of symbols in a frame 42 TTG+RTG µs

16 -16- Broadband IT Korea Key Features for Physical Layer 5 msec frame length : 42 OFDM symbols Flexible downlink and uplink time slot partitioning 5 ms Downlink Uplink Slot Group Bin TTG Slot Tile Bin RTG Band 0 Band 1 Λ Λ Λ Λ Band 2 Band 3 Λ Λ Μ Μ Λ Safety Channel Band B-2 Λ Λ Band B-1 Preamble Uplink Control Symbols

17 -17- Broadband IT Korea Downlink PHY Frame Structure Downlink Frame structure Symbol D D Λ D D A A A A A A A Μ Μ Band b-1 Band b Λ Λ Λ Λ Bin for AMC Subchannel Bin for Safety Subchannel Band b+1 Preamble Μ Λ Safety Channel Μ Λ Subcarrier for Diversity Subchannel

18 -18- Broadband IT Korea Uplink PHY Frame Structure Uplink Frame structure Slot Tile Bin Band 0 Λ Band 1 Λ Band 2 Safety Subchannel Band 3 Λ Safety Channel Μ Μ Μ Band B-2 Λ Bin Pilot Subcarrier Band B-1 Tile Uplink Control Symbols

19 -19- Broadband IT Korea Key Features for Physical Layer 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

20 -20- Broadband IT Korea Key Features for Physical Layer Band AMC Mode in Uplink and Downlink Fast CQI report for bands from user terminals are provided Power headroom report from user terminals for uplink band selection are provided Packet 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

21 -21- Broadband IT Korea Key Features for Physical Layer Full Diversity Mode Average CQI report for all bands from user terminals are provided Select appropriate modulation level and code rate in averaged C/I sense Tones for user-a Tones for user-b Tones for user-c freq time

22 -22- Broadband IT Korea Key Features for Physical Layer Ranging Object: 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

23 -23- Broadband IT Korea Key Features for Physical Layer 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 preambles Ranging 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

24 -24- Broadband IT Korea Key Features for Physical Layer CTC is baseline CTC (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 information CQI/ACK : Non-binary block coding Coded symbol scrambling Fixed PN Generator with Cell ID based masking Inter-cell interference from the same frequency bin can be randomized at the encoder output

25 -25- Broadband IT Korea Key Features for Physical Layer H-ARQ Supportable Coding CTC Encoder Interleaver Symbol Selection Uplink Puncturing A B A' B' CTC Interleaver 1 2 switch Constituent Encoder C 1 C 2 Interleaving Symbol Selection Z Puncturing AB Subblock Y1 Y2 W1 W2 Subblock Subblock Subblock Subblock Sub-block symbol separation, interleaving and grouping for H- ARQ support (IR scheme). Subblock Interleaver Subblock Interleaver Subblock Interleaver Subblock Interleaver Subblock Interleaver

26 -26- Broadband IT Korea Key Features for Physical Layer Incremental Redundancy based H-ARQ for uplink and downlink To mitigate the effect of channel and interference fluctuation Overcome adaptation error of AMC in fading channel To 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 feedback Maximum number of sub-packet retransmission depends on service classes Control for H-ARQ Physical Layer CRC Sub-Packet ID ARQ-Channel ID ARQ-ID Sequence Number UL-ACK/NAK Channel DL-ACK/NAK in MAP

27 -27- Broadband IT Korea Key Features for Physical Layer Uplink Control Channels-CQI, ACK, etc UL 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 ACK channel for MIMO mode and subcarrier permutation selection ACK/NACK feedback for HARQ operation

28 -28- Broadband IT Korea Key Features of MAC Layer 주요기능 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

29 -29- Broadband IT Korea Key Features of MAC Layer Resource Allocation (1) DL 서브프레임선두에서 AT 에대한 DL/UL 자원할당정보를표시하는 MAP 운용 DL-MAP 및 UL-MAP 은각각하향링크채널정보및상향링크채널정보를포함 DL 은 OFDMA/TDM 방식, UL 은 OFDMA/TDMA 방식으로전송

30 -30- Broadband IT Korea Key Features of MAC Layer Resource Allocation (2) MAP 사용법및전용피드백채널 Channel Transmission Information Downlink Frame Uplink Frame Tx. Period Remarks FCH Frame Control Header Every Frame General MAP pointing General MAP General MAP information Every Frame Compact MAP pointing Compact MAP (HARQ based) User data burst allocation Every Frame MAP AMC support Traffic Burst Traffic/Messages Traffic/Messages - Diversity Band AMC Safety Channel CQICH Channel Quality Periodic If allocated ACKCH H-ARQ Ack - Implicit Ranging CH Ranging Codes - Uplink synchronization

31 -31- Broadband IT Korea Key Features of MAC Layer Resource Allocation (3) MAP 구성정보 CID (Connection ID) DIUC/UIUC (Downlink/Uplink Interval Usage Code) OFDMA Symbol/Subchannel Offset

32 -32- Broadband IT Korea Key Features of MAC Layer Connection Management 기능및특징 Connection 용도및특징에따른 Connection ID (CID) 관리 CID 종류및용도 종류용도비고 Broadcast CID 방송정보전송 - Initial Ranging CID RNG-REQ/RSP 메시지전송 - Basic CID 지연민감한메시지전송 DL/UL 동일 Primary Management CID 상대적으로지연덜민감한메시지전송 DL/UL 동일 Secondary Management CID IP Management 패킷전송 DL/UL 동일 Transport CID 트래픽데이터전송 - Multicast Polling CID Multicast Polling 그룹에속한 AT 가 Polling 을통한자원할당요청시사용 - Padding CID 패딩정보전송 -

33 -33- Broadband IT Korea Key Features of MAC Layer Packet Transmission Control (1) Packet Classification IP Header 에의한 CID 매핑기능 Packet Convergence IP Header 압축 Packet Suppression 및 Compression 제공 IP Header Masking 기능 IETF ROHC 기능 ( 옵션 )

34 -34- Broadband IT Korea Key Features of MAC Layer Packet Transmission Control (2) MAC Header Format Generic MAC Header 트래픽데이터및 MAC Management Message 전송 (DL/UL) Bandwidth Request Header 자원할당요청용 (UL) Fragmentation Sub-header MAC CPS SDU 분할전송용 (DL/UL) Packing Sub-header MAC CPS SDU 연접전송용 (DL/UL) Grant Management Sub-header 전송방식 Piggybacking 자원할당요청용 (UL) Fragmentation SDU 를분할하여해당분할을하나의 PDU 로전송 Packing 여러 SDU 를연접하여하나의 PDU 로전송 Piggybacking Sub-header 를사용하여하나의 PDU 에 Piggybacking 하여전송 Generic MAC Header Bandwidth Request Header

35 -35- Broadband IT Korea Key Features of MAC Layer Packet Transmission Control (3) ARQ 다양한 ACK 피드백방식 Cumulative ACK Selective ACK Cumulative-Selective ACK Sequential ACK 타이머기반의재전송메커니즘 ARQ Block Lifetime ARQ Retry Lifetime Tx/Rx Window Purge Time 전용피드백채널운용 Dedicated ACK Channel Dedicated CQI Channel Flow Control 기능 SDU Discard Tx/Rx Window Change Not-sent Transmit Outstanding ACK ARQ_BLOCK_LIFETIME Done Retransmit ARQ_RETRY_TIMEOUT or NACK Discarded ARQ_BLOCK_LIFETIME ACK ARQ 메커니즘 Waiting-forretransmission ACK

36 -36- Broadband IT Korea Key Features of MAC Layer MAC Management 운용방식 MAC Management 를위한메시지정의 메시지에대응되는 CID 매핑 Generic MAC Header 로전송 메시지종류 기능관련메시지비고 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 Handover NBR-ADV, HO-REQ/RSP, SCN-REQ/RSP/REPORT -

37 -37- Broadband IT Korea Key Features of MAC Layer Idle Mode (1) 개념 AT 가여러 AP 에의해서관장되는영역을돌아다니면서특정한 AP 에등록되지않고도주기적으로 DL Broadcast 메시지를받을수있도록하기위한것 Idle Mode 에있는 AT 는 Handover 또는 Normal Operation 에따르는 Active Requirement 를지키지않아도됨 특정구간에서만 AT 자신이호출되었는지를체크하면서 Power Saving 운용을할수있음 AT 상태 모든 Active Connection 단절 Serving AT 에게모든 Management CID 및 IP Address 반환 Connection 설정절차없이 MBS 서비스받을수있음 Idle Mode 진입절차 AP 가 DREG-CMD 전송 (unsolicited) AT 가 DREG_REQ 전송후 AP 가 AP 가 DREG-CMD 전송

38 -38- Broadband IT Korea Key Features of MAC Layer Idle Mode (2) 기능및단계 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

39 -39- Broadband IT Korea Key Features of MAC Layer Handover (1) 주요특징및기능 Neighbor AP Advertisement 방송정보송신 Scanning 절차 AT 에의해서 Target AP 로타당한지를결정하기위해서 Neighbor AP 를탐색하는절차 Soft HO (SHO) 및 Fast BS Selection (FBSS) 지원 Anchor BS/Active BS 개념도입 Fast Anchor BS Selection Feedback Channel 사용 AT-initiated & AP-initiated HO 지원 HO Drop Situation 복구기능지원 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

40 -40- Broadband IT Korea Key Features of MAC Layer Handover (2) Scanning & HO Initiation AT-initiated HO AP-initiated HO

41 -41- Broadband IT Korea Key Features of MAC Layer Handover (3) HO Process AP 1 AP 2 AT 4. Cell Reselection AT Inter-Sector HO (AT-initiated) Inter-AP HO (AT-initiated)

42 Key Features of MAC Layer Handover (4) Soft Handover (SHO) DL 에서둘이상의 AP 가동시에해당 AT 로동일한 MAC PDU 를전송 UL 에서둘이상의 AP 가해당 AT 로부터동시에수신 (demodulation/decoding) Fast Base Station Selection (FBSS) 링크품질을향상시키기위하여 Selection Diversity 와 Switching Mechanism 을활용하는것 AT 는주어진프레임에서특정한 AP(Anchor AP) 와만데이터를주고받음 Anchor AP 는매프레임단위로변경될수도있음 Anchor AP -Anchor AP 는 MSS 에대한자원을할당하여야하는책임을가지는 AP -Basic CID, Primary Mgt CID, Secondary Mgt CID, & Transport CID 할당의책임 -AT 는항상 Anchor BS 와동기를유지하여야함 -Anchor BS 하고만 Ranging 을수행하여야함 -AT 는 DL 제어정보 (DL-MAP, UL-MAP, FCH, DL Broadcast message) 를수신하기위하여 Anchor AT 를모니터링함 Active AP -FBSS/SHO 절차에만적용 -Active Set 은해당 AT 에대한 Active AP 들의목록을포함 -Active BS 는해당 AT 의 MAC Information 에대한정보 (capability, security parameters, service flows) 를제공받음 -SHO 모드에서 AT 는모든 Active AP 들과데이터를송수신 -42- Broadband IT Korea

43 -43- Broadband IT Korea Key Features of MAC Layer 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 방식및 AK key 분배메시지가다름 RSA-based PKM 의경우 Authentication Information/Authorization Request/ Authorization Reply 메시지를통하여 Authorization 을처리하고 AP 에서 AK 키분배 EAP-based PKM 의경우 EAP-Transfer 메시지를통해 Authorization 을하고 AAA 서버에서 AK 키를관여하여분배 AK Key 분배 Attribute 동일 AK Key, Sequence Number, Lifetime TEK Key 요청및분배처리동일

44 -44- Broadband IT Korea Key Features of MAC Layer Security (2) 절차 AT AP PAR AAA SBC-REQ (Authorization Policy Negotiation) SBC-RSP Regacy PKM PKM-REQ/Authentication Information PKMv2-EAP PKM-REQ/Authorization Request PKM-RSP/Authorization Reply PKM-REQ/EAP-transfer (EAP Payload). PKM-RSP/EAP-transfer (EAP Payload) PKM-REQ/key request PKM-RSP/key reply (TEK key, sequence number, IV) ADTcmd (additional information, EAP Payload) ADTcmd (additional information, EAP Payload) Diameter(EAP-TLS) Diameter(EAP-TLS) EAP-TLS User Authentication and AK Distribution base on EAP-TLS PKM-REQ/RSP Messages (for PKM v2) -EAP Transfer message -EAP Keying message -Pre-Authentication message -Mutual-Authentication message

45 -45- Broadband IT Korea Key Features of MAC Layer HARQ Supporting HARQ 용 Compact MAP 을사용하여해당 AT 에자원할당 Basic CID, Nep/Nsch for AT #A Basic CID, Nep/Nsch for AT #B FCH Compact MAP 1 General MAP MAP IE MAP IE Compact MAP 2 MAP IE Compact MAP 3 MAP IE MAP IE DL Burst #1 DL Burst #2 DL Burst #3 DL Burst #4 DL Burst #5 DL Burst #6 DL Burst #7 CQI CH ACK CH Ranging Subchannel UL Burst #1 UL Burst #2 UL Burst #3 : HARQ_Pointer_IE Basic CID, Nep/Nsch for AT #D Basic CID, Nep/Nsch for AT #C

46 -46- Broadband IT Korea Key Features of MAC Layer Ranging Supporting (1) Ranging 방식비교 메시징방식 CDMA 방식 Initial Ranging Periodic Ranging Contention-based Contention-based Unicast-polling Unicast-polling Contention-based Contention-based Ο 2 Unicast-polling Unicast-polling Ο 1 : 불가능, Ο: 가능 ( 채택 ), : 불가능하지는않으나, 효율성및구현측면에서채택하지않음 Ο 1 : CDMA-based Ranging (status = success 인 RNG-RSP 수신 ) 후, CDMA_Allocation_IE 에할당된 UL 구간으로 RNG-REQ (with MAC Address) 메시지전송 Ο 2 : CDMA-based Ranging 절차만계속 (status = success 가될때까지 )

47 -47- Broadband IT Korea Key Features of MAC Layer Ranging Supporting (2) Initial Ranging 절차 AP AP AP AP AP AP AP AP AP DCD/UCD/ DL-MAP UL-MAP RNG-REQ (Code) Binaryexponential Random Backoff RNG-REQ (Code) RNG-RSP (Continue) RNG-REQ (Code) RNG-RSP (Success) UL-MAP RNG-REQ (MAC_Address) RNG-RSP (Management CIDs) AT AT AT AT AT AT AT AT AT 1) DL Sync 2) UL Burst 정보획득 3) UL-MAP Scan 4) Random Subch, Symbol, Code 선택 5) Ranging Code 전송 6) Backoff 7) Ranging Code 전송 Timer T3 Expire 8) Timing, Power, & Frequency Adjustment 9) Random Subch, Symbol, Code 선택 10) Ranging Code 전송 11) RNG-RSP (Success) 수신 mapped with transmitted Subch, Symbol, & Code 12) RNG-REQ message 전송 with MAC Address 13) RNG-RSP (Management CIDs) 수신

48 -48- Broadband IT Korea Key Features of MAC Layer Ranging Supporting (3) Periodic Ranging 절차

49 -49- Broadband IT Korea Key Features of MAC Layer Bandwidth Request (1) BW Request 제공방식 제공방식기능요청방식 Unicast Polling Piggybacking BW Stealing CDMA-based Request UL-MAP 지정에의해특정 AT 에할당된 UL 자원상으로 BW Request Header 전송 동일한 CID 에대한 BW Request 할당요청의경우, UL 데이터전송을위한자원이가용할때, Grant Management Subheader 를추가하여전송 Data 전송용으로할당된자원을 AT 의판단에따라 BW Request Header 를전송하기위한목적으로전용하여사용 BW Request 용 CDMA Code 를 Ranging Domain (UIUC = 11) 에서전송 / 성공후, AP 에의하여할당되는 UL-MAP 의 CDMA_Allocation_IE 에의하여주어지는 UL 자원을사용하여 BW Request Header 전송 Aggregate/ Incremental Incremental Aggregate/ Incremental Aggregate/ Incremental CDMA-based Request 는 Ranging (Random Access) 및 UL 자원할당의두단계를가진다.

50 -50- Broadband IT Korea Key Features of MAC Layer Bandwidth Request (2) CDMA-based BW Request 절차

51 -51- Broadband IT Korea Key Features of MAC Layer MBS (1) MBS 여러개의 AP 들에의한 Synchronized Transmission 을통하여별도의 Network Entry 절차를거치지않고도다수의 AP 에걸쳐끊임없는 Multicast/Broadcast Service 제공 MBS Zone 하나의 MBS Service Flow 에대하여 CID 및 SA 가유효한영역 하나의 AP 는여러개의 MBS Zone 에대응될수있음 MBS Security Association MBS Group Security Association (MBS GSA) 는 AP 에서제공 MBS GSA 정보 Cryptographic Suite Key Material» MBS Authorization Key (MAK),» MBS Group Traffic Encryption Key (MGTEK) Lifetime MBS Traffic Encryption AES CTR Mode 사용 PDU 는 MBS Traffic Key (MTK) 를사용하여 Encryption 함 MTK 는 MAK 및 MGTEK 를사용하여생성

52 -52- Broadband IT Korea Key Features of MAC Layer MBS (2) MBS MAC PDU Ciphertext Payload Format MBS-MAP AP 는해당 MBS Zone 에서서비스되는 MBS Connection 들을기술하기위하여 MBS- MAP message 전송 MBS Burst 할당정보포함 CID Use 특정한영역에있는 Dedicated Multicast CID 들사용 동일한 MBS_Zone 에속하는 AP 들은동일한 CID 를사용 CID 할당은 MBS Content Server 가관리 Macro-diversity Gain: MBS_Zone 내의인접한 AP 들에서동일한데이터 (PDU Header, Payload; 동일한 Channel Coding, Modulation 및변조방식사용 ) 를동일한심볼구간및 Carrier 로전송하여 Diversity Gain 획득

53 -53- Broadband IT Korea Key Features of MAC Layer MBS (3) Register 특정셀에등록되지않은채로 Idle Mode 및 Sleep Mode 에서 MBS service 유지가능 SA Capability MBS 용 GSA (MBS-GSA) 와매핑 Data Encryption Application Layer 및 MAC Layer 에서의 Data Encryption 둘다지원 MAC Encryption 은 AES-CTR Mode 만사용가능 Power Saving Operation MBS-MAP 을사용하여 MBS Burst 들에적용될 Physical Attributes 뿐만아니라각각의 Connection 에대한다음에전송될프레임및그프레임에서의위치에대한정보도제공 Scheduling 을통하여 Power Saving 을극대화할수있음

54 -54- Broadband IT Korea 감사합니다. Thank You for Listening!!! Fourth Generation