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Case Study: WiBro MAC. 2007.10. 미래기술연구소. 목차. PART I : Basic Topics Introduction to MAC Convergence sublayer MAC PDU Ranging MAP PART II: Advanced Topics (For your reference) Basic Access Procedure QoS Sleep mode Idle & Paging Handover. WiBro System. Definitions (1/3).

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slide1

Case Study: WiBro MAC

2007.10

미래기술연구소

slide2
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics (For your reference)
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
definitions 1 3
Definitions (1/3)
  • Base Station (BS)
    • SS의 연결, 관리 및 제어 기능을 제공하는 일반화된 장치의 집합
    • Serving BS (16e scope)
      • SS가 최근에 등록을 수행한 BS
    • Target BS (16e scope)
      • SS가 핸드오버 마지막 과정에서 등록을 하려고 하는 BS
  • Subscriber Station (SS)
    • 가입자 장치(UE)와 BS사이의 연결성을 제공하는 일반적인 장치
    • MSS (Mobile Subscriber Station): SS with Mobility (16e scope)
    • PSS (Portable Subscriber Station): MSS in WiBro (TTA)
definitions 2 3
Definitions (2/3)
  • Connection
    • 하나의 Service flow의 트래픽을 전송
      • BS와 SS의 MAC peer들 사이의 unidirectional mapping
  • Connection Identifier (CID)
    • BS와 SS의 MAC계층 내의 connection을 식별하는 MAC계층 주소
    • Unidirectional Connection ID
  • Connection의 종류
    • Basic Connection
      • Initial SS ranging동안에 설정 (RNG-RSP)
      • 지연에 민감한 MAC mgmt. 메시지들을 전송
    • Management Connection
      • 지연에 민감하지 않은 MAC mgmt.메시지들을 전달
      • Primary mgmt. connection; Secondary mgmt. connection
    • Transport Connection
      • 사용자의 데이터를 전송하기 위하여 사용되는 연결
definitions 3 3
Definitions (3/3)
  • MAP
    • DL/UL에서 주파수 및 시간상 자원을 정의하는 MAC계층의 메시지
      • 자원 위치와 Offset으로 자원 살당 (Subchannel 및 Symbol)
      • Downlink MAP (DL-MAP); Uplink MAP (UL-MAP)
  • Channel Descriptor
    • DL/UL에서 PHY/MAC 특성을 기술하는 MAC message
      • Downlink Channel Descriptor (DCD), Uplink Channel Descriptor (UCD)
  • Interval Usage Code (IUC)
    • Burst profile을 식별하는 부호
      • Downlink Interval Usage Code (DIUC); Uplink Interval Usage Code (UIUC)
        • 프로파일 (profile)은 변조방식; 순방향 오류정정 방식; 프리앰블 길이; 보호기간 등을 포함
reference model
Reference Model
  • Convergence Sublayer (CS)
    • DL(BS), UL(SS): Classifying SDUs to CID
    • Payload header suppression
  • MAC CPS
    • Bandwidth allocation
    • Connection establishment
    • Connection maintenance
    • Quality of Service
    • Scheduling of data over the PHY
  • Privacy Sublayer
    • Providing authentication
    • Secure key exchange
    • Encryption
slide9
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
slide17
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
payload with gmh
Payload with GMH
  • Fragmentation and Packing
    • Subheaders: Fragmentation subheader /Packing Subheader
    • MAC SDU and MAC management message -> MAC PDU
pdu handling 1 2
PDU Handling (1/2)
  • Concatenation
    • Burst를 구성하는 PDU를 연접하여 전송하는 것 (GMH를 사용)
    • MAC PDU Concatenation Example
    • Fragmentation
      • SDU를 분할하여 PDU들에 나누어 전송하는 것 (Fragmentation Subheader를 사용)
      • MAC PDU Concatenation Example
pdu handling 2 2
PDU Handling (2/2)
  • Packing
    • 다수 개의 SDU 또는 SDU fragment들이 PDU를 구성하는 것
    • MAC PDU Packing Example – Packing with fragmentation
arq mechanism
ARQ Mechanism
  • ARQ (Automatic Repeat reQuest)
    • MAC Layer의 optional 기능
    • Connection 설정시 ARQ 사용여부 결정
    • Per-connection basis로서 수행
    • Cumulative/Selective ACK를 가지는 Selective Repeat ARQ bitmap방식으로서 Bitmap Block의 크기를 가변적으로 운용 가능함
pac pdus
PAC PDUs
  • With Generic MAC Header (GMH) and CRC
    • Subheader (SH) and extended subheader (ESH): HT=0
    • Only with MAC Header
    • No CRC But the field of “header check sum” protects it
    • Small size
    • Header type (HT) =1
    • Bandwidth request header
    • Several headers (8 ones in 16e/D6)
slide24
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
slide30
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
normal map
Normal MAP
  • DL-MAP & UL-MAP
    • Management Messages (GMH and CRC0
    • DL-MAP IEs and UL-MAP IEs
    • Burst Profile 방식 (DIUC and UIUC)
data identification in map
Data Identification In MAP
  • Allocation Unit
    • Per-Burst: 동일한 변조/코딩을 사용하는 데이터의 집합
      • 다른 사용자들의 CID를 모음
    • Per-User: 사용자 단위 데이터 (CID)
  • Burst Profile방식
    • 데이터의 크기와 상관없이 변조 및 채널 코딩 결정
    • 채널 상태(SNR)변조 및 채널코딩 결정
    • DL: DIUC & UL:UIUC
      • Ex) DIUC 0 = [QPSK (CTC) 1/2]
    • Nep & Nsch 방식
      • Nep: 입력 데이터 양, Nsch: 할당된 sub-channel 양
      • 데이터 크기에 따라 변조 및 채널코딩 결정
      • 채널 상태 (SNR)+Nep  변조 및 채널 코딩 결정
compressed map
Compressed MAP
  • Compressed DL-MAP & Compressed UL-MAP
    • No GMH and one CRC
    • DL-MAP IEs and UL-MAP IEs
    • Burst Profile 방식 (DIUC and UIUC)
harq map
HARQ MAP
  • HARQ MAP Message
    • Different modulation and channel coding with MAP
    • HARQ for downlink and uplink
    • Compact DL-MAP IEs and compact UL-MAP IEs
    • Nep & Nsch 방식
slide35
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
access procedures
Access Procedures
  • 셀 방송정보 (UCD/DCD)
  • 초기 무선 접속 (Initial RNG)
  • AT 기본 협상
  • 장치 및 사용자 인증
  • 셀 등록
  • IP 연결
  • 서비스 흐름 추가/변경/종료
  • 등록 해제
ap initialization
AP Initialization
  • 셀 초기화 관리
    • 셀 설정
    • SI 설정 (UCD/DCD)
    • 방송 정보 설정
  • 상태 관리
  • 셀 해제 관리
    • 정상: 셀 해제
    • 오류: 셀 재시작
basic access
Basic Access
  • 셀 방송정보
    • UCD/DCD
    • UL-MAP/DL-MAP
  • 초기 무선접속
    • CDMA Ranging
    • Initial Ranging
  • AP 기본 기능협상
  • 장치 및 사용자 인증
    • EAP지원
  • 셀 등록
  • IP 연결
    • Mobile IP
traffic access and deregistration
Traffic Access and DeRegistration
  • 서비스 흐름 추가
    • 무선 트래픽 추가
    • MAC: DSA-XXX
    • ANAP: DSAxxx
  • 서비스 흐름 변경
    • 무선 트래픽 변경
    • MAC: DSC-XXX
    • ANAP: DSCxxx
  • 서비스 흐름삭제
    • 무선 트래픽 삭제
    • MAC: DSD-XXX
    • ANAP: DSDxxx
  • AT접속 해제
    • DREG-CMD
slide48
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
qos objective model
QoS Objective Model
  • Service Flow and Service Class
  • Connection ID
service types
Service Types
  • Unsolicited Grand Service (UGS)
    • T1/E1 및 voice over IP without suppression 등과 같은 고정된 크기의 데이터 패킷들을 생성하는 real-time service flow들을 지원함
  • Real-Time Variable Rate (RT-VR)
    • MPEG video 등과 같은 주기적인 가변크기의 데이터 패킷들을 생성하는 service flow들을 지원함
  • Extended Real-Time Variable Rate (ERT-VR)
    • UGS + RT-VR
  • Non-Real-Time Variable Rate (NRT-VR)
    • High bandwidth FTP등과 같은 가변 크기의 Data Grant Burst Type들을 regular basis로서 필요로 하는 service flow들을 지원
  • Best Effort (BE)
    • WWW등과 같은 Best Effort Traffic에 대하여 효과적인 서비스를 제공하기 위한 것
uplink
Uplink자원 요청 및 할당 정책
  • UGS (Unsolicited Grand Service)
    • Connection 설정시 고정 대역을 할당 받는다. SI (Slip Indicator) bit가 설정된 경우를 제외하고는 Maximum Sustained Traffic Rate Parameter보다 많은 대역폭을 할당받을 수 없음
  • rtPS (real-time Polling Service)
    • Connection설정시 polling 주기를 할당 받아 BS로부터 poll을 받으면, 매 PDU 전송마다 bandwidth request 또는 piggybacking으로 자원 요청
  • ertPS (extended real-time Polling Service)
    • UGS + rtPS
  • nrtPS (non-real-time Polling Service
    • BS의 상황에 따라 정규적으로 (periodic or non-periodic) poll될 때 bandwidth request를 하거나, connection based로 요청할 수 있음
  • BE (Best Effort)
    • Connection based 또는 piggybacking으로 자원을 요청할 수 있음
slide52
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
sleep mode operation 1 2
Sleep Mode Operation (1/2)
  • IEEE 802.16e Sleep-Mode
    • Awake Mode: SS는 정상적인 방법으로 PDU들을 수신/전송
    • Sleep Mode: SS는 PDU들을 수신하거나 전송하지 않음
  • Definitions of Two intervals during Sleep Mode
    • Sleep-interval:
      • Sleep mode로 동작하는 구간
      • Sleep period 동안에 minimum부터 maximum limits까지 지수적으로 증가
    • Listening-interval
      • Awake mode로 상태변경을 BS가 알려주는 지속 시간
      • DL transmission과 동기를 맞추고 DL데이터를 복조 할 수 있음
  • Sleep Mode의 동작
    • Sleep mode로 들어가기 이전에 SS는 BS에게 통지 및 승인이 필요
    • Sleep mode동안 BS는 incoming PDU들을 저장
      • Listening-interval에 DL 데이터 유무를 통지
      • 통지 후 Awake mode로 복귀
    • SS는 sleep mode를 종료하고, 언제라도 awake mode로 복귀 가능
sleep mode operation 1 21
Sleep Mode Operation (1/2)
  • Sleep Interval Update Algorithm
    • SS는 SLP-RSP message를 수신한 이후에 sleep mode로 진입
    • SS는 sleep mode로 진입할 때, sleep-interval에 대하여 min-window를 사용
    • 이후 sleep-interval의 지속시간을 두 배로 하여 다시 sleep-mode로 재진입
    • 이 절차는 sleep-interval이 max-window를 넘지 않을 때까지 계속되고, 이후 max-window크기인 sleep-interval이 반복됨
  • Traffic Indication Signaling
    • SS는 동기가 맞지 않는 경우 Awake mode로 복귀
      • PHY의 frame number가 expected frame number와 다른 경우
    • BS는 traffic 유무를 listening interval동안에 통지 (TRF-IND)
    • SS가 자신의 CID에 대하여 Positive Traffic Indication을 발견하지 못하면, sleep-mode로 복귀
sleep mode example
Sleep Mode Example
  • Example: Sleep Mode Operation – HPi & 802.16e Harmonization
sleep mode additional functions
Sleep Mode: Additional Functions
  • Sleep Mode Operation (additional functions)
    • SLPID Update
    • Periodic Ranging During Sleep Mode
    • SLPID Grouping Indication
    • Guaranteed Mode of Minimum Sleep Duration
    • Power Saving Classes, etc
power saving class 1 2
Power Saving Class (1/2)
  • Power Saving Classes
    • Power saving class 1:
      • Recommended for connections of BE and NRT-VR type
      • Relevant parameters
        • Initial-sleep window
        • Final-sleep window base
        • Listening window
        • Final-sleep window exponent
        • Start frame number for initial sleep window
        • Traffic triggered wakening flat
      • Sleep window update algorithm

Sleep_window = min (2*(Previous_sleep_window),

Final_sleep_window_base*2^(Final_sleep_window_exponent))

power saving class 2 2
Power Saving Class (2/2)
  • Power Saving Classes
    • Power Saving Class 2:
      • Recommended for connections of UGS, RT-VR type
      • Relevant parameters
        • Initial-sleep window
        • Listening window
        • Start frame number for initial sleep window
    • Power Saving Class 3:
      • Recommended for multicast connections as well as for management operations, for example, Periodic Ranging, DSx operations, NBr-ADV
      • Relevant parameters
        • Final-sleep window base
        • Final-sleep window exponent
        • Start frame number for sleep window
sleep mode operation
Sleep Mode Operation
  • Example: Sleep Mode operations with two Power Saving Classes
slide60
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
idle mode
Idle Mode
  • Idle Mode
    • Concept
      • MSS가 DL broadcast messaging을 받으면서 다수 BS는 이동
      • MSS가 handover나 normal operation에 요구사항을 따르지 않음
      • Discrete interval에만 호출여부를 점검하여 power save를 할 수 있는 상태
    • Conditions
      • 모든 connection 및 management connection ID들은 해제/반납됨
      • ID address도 반납됨
      • MBS service flow 및 SA는 유지
    • Idle Mode Entering procedure
      • BS-initiated unsolicited DREG-Cmd Message (code=0x05)
      • MSS-initiated DREG-REG, then the BS shall Tx DREG-Cmd (code=0x05)
paging listening unavailable
Paging Listening & Unavailable
  • MSS Broadcast paging Message time synchronization
    • Preferred BS의 평가 및 선택:DCD 및 DL-MAP수신
    • MSS Paging Unavailable Interval
    • MSS Paging Listening Interval
  • MSS paging Unavailable interval
    • 수행 가능한 동작
      • Power down
      • Scan neighbor BSs
      • Re-select Preferred-BS
      • Ranging trial
      • 기타 다른 action들을 수행
paging cycle
Paging Cycle
  • BS Paging Interval
    • BS Paging interval은 다음을 만족하는 frame에서 시작하는 5 frame구간임
      • N_frame modulo PAGING_CYCLE == PAGING_OFFSET
    • BS는 backbone message를 통하여 실제 PAGING_CYCLEs를 통보 받음
    • BS Broadcast Paging message
      • 단말기에게 다음 사항을 알려줌
        • BS또는 어떤 network entity를 통하여 pending서비스 요청
        • Location update를 수행하도록 poll
      • Broadcast CID를 사용하여, BS Paging Interval동안 전송
      • MSS를 식별하기 위하여 MSS MAC Address Hash를 포함
paging location update
Paging & Location Update
  • Paging and Location Update
    • Paging and Location Update
      • Paging Group ID, Paging Cycle, Paging Offset값에 의해 Paging interval동안에 paging가능 (Paging controller/serving BS에 의하여)
      • RNG-REG/RSP 메시징을 통하여 Location Update가능
    • Location Update Types
      • Zone-based (Paging Group ID change detection) Location Update
      • Timer-based Location Update
      • Power down-based Location Update
      • MAC hash Skip Threshold-based Location Update
    • Location Update Process
      • Secure Location Update
        • RNG-REG msg내에 Ranging Purpose Indication “Location Update Request” & paging controller ID TLV & HMAC Tuple을 포함하여 전송
      • Un-secure Location Update
        • RNG-REG msg without HMAC Tuple
slide68
목차
  • PART I : Basic Topics
    • Introduction to MAC
    • Convergence sublayer
    • MAC PDU
    • Ranging
    • MAP
  • PART II: Advanced Topics
    • Basic Access Procedure
    • QoS
    • Sleep mode
    • Idle & Paging
    • Handover
handover types
Handover Types
  • Handover Types
    • Inter-Sector Handover
    • Inter-BS(RAS) Handover
    • Inter-ACR Handover
  • HO Type based on Initiator
      • MS-initiated HO
      • BS-initiated HO
  • L2 Connection Types
    • Hard HO
    • Fast BS Switching (FBSS)
    • Soft HO: Macro Diversity HO (MDHO)
  • Specification of L3 Handover
    • Out of Scope of IEEE 802.16
    • Link extension (tunneling) or MIP
neighbor bs information
Neighbor BS Information
  • Trade-off of MOB_NBR-ADV Interval
    • Acquisition Time
    • Broadcast Data Overhead
scan and periodicity
Scan and Periodicity
  • Scanning
    • Scanning without Association
    • Scanning with Association
    • Determined by “Scanning Type”
    • Multiple Scanning Intervals
  • “Trigger” in DCD
    • Type/Function/Action descriptor
    • Controls scanning request, scanning report and HO initiation
scan and association
SCAN and ASSOCIATION
  • Scanning
    • Message based scanning procedure and iterative scanning interval
    • No downlink data during scanning interval
  • Association
    • Optional initial parameter negotiation when scanning
    • Purpose of association
      • To select the proper target BS for HO
      • To expedite a potential future HO to a target BS
      • By acquiring and recording ranging parameters and service availability information
associaton levels
ASSOCIATON LEVELS
  • Three Association levels
    • Association level 0: contention-based ranging
    • Association level 1: non-contention-based ranging
    • Association level 2: non-contention-based ranging, no wait for RNG-RSP
ho decision parameters
HO Decision Parameters
  • HHO: Hysteresis margin & Time-to-Trigger margin in DCD msg.
  • SHO: H_Add_Threshold & H_Delete_Threshold in DCD msg.
  • Trigger in DCD message
fbss sho
FBSS & SHO
  • FBSS (Fast BS Switching)
    • An MS receives/transmits data from/to only one BS, an anchor BS
  • SHO (Soft HO)
    • An MS receives/transmits data from/to all BSs in the current Active Set.
conditions for fbss sho
Conditions for FBSS/SHO
  • FBSS
    • BSs are synchronized based on a common time source
    • Frames from any BSs in Active Set arrive at the MS within the prefix interval
    • BSs have synchronized frames
    • BSs operate at the same frequency channel
    • BSs are required to share or transfer MAC context
  • SHO
    • All conditions required to enable FBSS
    • BSs shall use the same set of CIDs for the connections that are established with the MS
    • The same MAC/PHY PDUs shall be multicast by the Bses to the MS
    • Monitoring method of DL control information and DL broadcast messages
      • DL-MAP & UL-MAP of the anchor BS
      • DL-MAPs & UL-MAPs of all the active BSs
active set update add
ACTIVE SET UPDATE (ADD)
  • Control of Active Set
    • H_ADD_Threshold (DCD)
    • H_Delete_Threshold (DCD)

MSS

BS1

BS2

anchor bs update fast feedback ch
ANCHOR BS UPDATE: FAST-FEEDBACK CH
  • Anchor BS report
    • 8 codewords numbered from 32 to 39
    • Each codeword maps to one of TEMP BS ID
  • Fast-feedback CH allocation from a new Anchor BS
    • Pre-allocated by MOB_BSHO-RSP or MOB_BSHO-REQ
    • Anchor_Switch_IE during anchor switching operation
    • UL-MAP of the new anchor BS after the switching period
  • Cancellation of Anchor BS Update be MS
    • MS can not cancel anchor BS update during anchor switching operation
    • MS stay with the previous Anchor BS and transmit the CQI on the same CQICH allocated by the previous anchor BS
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