Case Study: WiBro MAC
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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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Case study wibro mac

Case Study: WiBro MAC

2007.10

미래기술연구소


Case study wibro mac

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

WiBro System


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


Functional model

Functional Model


Case study wibro mac

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


Packet header suppression phs

Packet Header Suppression (PHS)


Packet header suppression phs1

Packet Header Suppression (PHS)

  • ATM CS


Header compression

Header Compression


Suppression compression

Suppression & Compression


Packet classification

Packet Classification


Packet classification1

Packet Classification


Mac connection and cid

MAC Connection and CID


Case study wibro mac

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)


Mac pdus with gmh ht 0

MAC PDUs with GMH (HT=0)


Case study wibro mac

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


Ranging and bw request

Ranging and BW Request


Initial ho ranging

Initial & HO Ranging


Periodic ranging

Periodic Ranging


Up link bw request

UP Link BW Request


Cdma code based

CDMA Code-Based


Case study wibro mac

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


Case study wibro mac

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


Ss initialization overview

SS Initialization Overview


Mac synchronization

MAC Synchronization


Dcd parameter update

DCD Parameter Update


Network entry initial ranging

Network Entry – Initial Ranging


Network entry sbc negotiation

Network Entry – SBC negotiation


Network entry registration

Network Entry - Registration


Network entry provisioned connection

Network Entry – Provisioned Connection


Network entry ip connectivity

Network Entry – IP Connectivity


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


Case study wibro mac

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


Case study wibro mac

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


Case study wibro mac

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


Pss initiated idle mode transition

PSS-initiated Idle Mode Transition


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 procedure

Paging Procedure


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


Fast re entry procedure from idle mode

Fast Re-entry Procedure from Idle Mode


Case study wibro mac

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


Wibro system architecture

WiBro System Architecture


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 ho initiation

    SCAN and HO initiation


    Ho ranging

    HO Ranging


    Neighbor bs scanning

    Neighbor BS Scanning


    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


    Handover decision

    Handover Decision


    Ho procedure in serving bs

    HO procedure in serving BS


    Ho procedures

    HO Procedures


    Example inter ap ho procedure

    Example: Inter-AP HO procedure


    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


    Active set update drop

    ACTIVE SET UPDATE (DROP)


    Anchor bs update

    ANCHOR BS UPDATE


    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


    Case study wibro mac

    Thank you for your kind attention!


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