seamless services in vertical handover -...

Seamless Services in Vertical HandoverSeamless Services in Vertical Handover

4G Forum4G Forum

건국대학교새천년기념관

2007. 11. 212007. 11. 21

JaeJae--Hyun KimHyun Kim

(([email protected]@ajou.ac.kr))

School of Electrical Engineering School of Electrical Engineering Ajou University, KoreaAjou University, Korea

Homepage: http://Homepage: http://ajou.ac.kr/~jkimajou.ac.kr/~jkim

목차목차

핸드오버기술개요

2계층이동성보장기술3계층이동성보장기술4계층이동성보장기술수직핸드오버기술

결론

2

핸드오버핸드오버 기술기술 개요개요

−−국내국내이동통신이동통신서비스서비스현황현황

−−이동통신망이동통신망상호상호공존공존요인요인

−−핸드오버핸드오버정의정의

−−핸드오버핸드오버기술기술분류분류

−−핸드오버핸드오버평가평가척도척도

−−계층별계층별핸드오버핸드오버기술기술

3

핸드오버핸드오버 기술기술 개요개요

국내이동통신서비스현황

이동통신망상호공존요인

핸드오버정의

핸드오버기술분류

핸드오버평가척도

계층별핸드오버기술

4

용어용어 정의정의

이동단말MN (Mobile Node), MS (Mobile Station), UT (User Terminal)

기지국또는접속점

AP (Access Point), BS (Base Station)PoA (Point of Attachment)

CoA (Care-of-Address)RCoA (Regional Care-of-Address)LCoA (On-link Care-of-Address)

RouterPAR (Previous Access Router)NAR (New Access Router)MAP (Mobility Anchor Point)MAG (Mobile Access Gateway)LMA (Local Mobility Anchor)

5

2세대 CDMA고속의이동속도에서음성, 간단한데이터서비스제공

3세대WCDMA영상통화와같은대용량서비스제공가능

WLAN고속의데이터를낮은서비스비용으로제공

WiBro이동환경에서WLAN에준하는전송속도제공

- CDMA : Code Division Multiple Access - WCDMA : Wideband CDMA - WLAN : Wireless Local Area Network

국내국내 이동통신이동통신 서비스서비스 현황현황

6

IEEE802.11n

Transmission Rate

2G cellular

km/h

1 10 100

Mob

ility

2G cellular

1000 Mbps

3

100

250

3G cellular

IEEE 802.16e

IEEE 802.11n

3G evolution&

IEEE 802.16mevolution

Next Generation WLAN

이동통신망이동통신망 상호상호 공존공존 요인요인

이동통신망상호공존요인경제적요인

기존통신망의재활용을통한망설치비용절감

서비스특성에따른망선택을통한서비스비용절감

기술적요인

단일통신망으로사용자의요구를만족시키기어려움

높은전송속도, QoS, 고속의이동속도

7

통신망의변경에따른서비스의단절을줄이기위한이동성보장기술필요

핸드오버의핸드오버의 정의정의

IETF (Internet Engineering Task Force)서비스를받고있는단말이 PoA를변경하거나변경을시도하는과정[1]

WINNER (Wireless World Initiative New Radio)접속망에서정의된베어러(bearer) 서비스를제공하기위하여사용중인무선송수신기/시스템모드/무선시스템을변경하는과정[2]

IEEE 802.21 MIH(Media Independent Handover)링크스위치이벤트의발생시MN에서트래픽플로우의특성을유지하기위한과정[3]

8

[1] J. Maner, and M. Kojo,“Mobility related Terminology,“ RFC3753, Jun., 2004[2] WINNER, “D4.1: Identification and definition of cooperation schemes between RANs “, internal deliverable, IST-2003-507581 WINNER, Jun., 2004[3] IEEE P802.21™/D01.00, “IEEE P802.21/D01.00 Draft IEEE Standard for Local and Metropolitan Area Networks: Media Independent Handover

Services,” Mar., 2006

핸드오버핸드오버 기술기술 분류분류

9

Handover classification

Necessity of handover

Network types involved Frequencies engaged

Triggering object User control allowance

Number of connection involved

Handover In

same Network

technology

HandoverIn

different network

technology

Horizontal handover

Verticalhandover

Handover between

access pointoperating on same frequency

Handover between

access pointoperating

on different frequency

Intra-frequency

Inter-frequency

Mobile initiatedBS initiated

Mobile decisionBS decision

Initiation Decision

User sets Preference of

handover decision

User cannot control

handover decision

Proactivehandover

Passivehandover

Handover must be executedin order to

avoid disconnect

Handover may be executed to improve

the quality ofservice

Obligatoryhandover

Voluntaryhandover

Mobile node maintain only one

connection

Mobile node can maintain more than two

connection

Hard Handover

SoftHandover

Mobile node switches

connections In same

access point

SofterHandover

[4]N. Nasser et al, “Handoffs in Fourth Generation Heterogeneous Networks” IEEE Commun. Mag., vol. 44, no. 10, Oct. 2006, pp. 96-103.

핸드오버핸드오버 평가평가 척도척도

10

척도

신뢰성(Reliable)

연결성(Seamless)

간섭회피율(Interference Prevention)

부하제어(Load

Balancing)

핸드오버

수행횟수

정의 필요기술

• 핸드오버 이후 서비스의 품질이 일정하게유지되는정도

• 핸드오버를수행할단말에게제공할수있는서비스품질정보를기반한핸드오버결정기술

• 핸드오버를 수행하는 동안 서비스의품질이일정하게유지되는정도

• 핸드오버의이전에이동단말에관한정보를상호교환하는기술

• 핸드오버 수행 단말의 무선 채널과동일 또는 인접 채널을 사용하는 단말로인한간섭에대한회피정도

• 송신전력을제어하는전력제어기술• 간섭회피기술

• 기지국 또는 접속점의 가용한 자원을균일하게유지하기위한제어

• 기지국간부하제어기술• 셀부하정보를기반으로하는핸드오버결정기술

• 한번의 품질저하 극복 및 서비스 요구를충족시키지위해시행되는핸드오버횟수

• 상대적임계값을이용한핸드오버결정기술

[4]N. Nasser et al, “Handoffs in Fourth Generation Heterogeneous Networks” IEEE Commun. Mag., vol. 44, no. 10, Oct. 2006, pp. 96-103.

계층별계층별 핸드오버핸드오버 기능기능

11

Layer 2

Layer 2.5

Layer 3

Layer 4or upper

22계층계층 이동성이동성 보장보장 기술기술

−−핸드오버핸드오버관련관련정보정보측정측정기술기술 (Scanning)(Scanning)−−트리거트리거 (Initiation)(Initiation)−−핸드오버핸드오버결정결정 (Decision)(Decision)−−핸드오버핸드오버수행수행 (Execution)(Execution)−−상향링크상향링크정보를정보를이용한이용한핸드오버핸드오버

12

22계층계층 이동성이동성 보장보장 기술기술 과정과정

13

Serving cellServing cell Target cellTarget cell

Measurement

Trigger

Trigger threshol

d

Hysteresis

Decision & Execution

핸드오버핸드오버 관련관련 정보정보 측정측정 기술기술

현재통신조건에적합한무선통신망을찾기위한정보의

획득방법

측정정보

물리계층측정정보 : 신호세기 (RSSI), 신호대잡음및간섭비율 (SNR, SINR)

상위계층측정정보 : 셀부하, 사용자선호정보, QoS 제공정도

측정대상

Preamble signal, feedback report, pilot channel

WINNER 프로젝트의측정요구사항

Signal strength, Transmitted power, Quality, Cell load

14- RSSI : Received Signal Strength Indicator - SNR : Signal to Noise Ratio-SINR : Signal to Interference plus Noise Ratio

핸드오버핸드오버 관련관련 정보정보 측정측정 기술기술::LocationLocation--based Vertical Handoverbased Vertical Handover

이종망간핸드오버를용이하게하기위하여WINNER 프로젝트에서제안[5]

1. UT가주기적으로채널정보전송2. BS또는 AP는전송된채널정보와위치정보를 HIS(Hybrid Information System)

DB로저장3. 수직핸드오버의필요시 BS또는 AP에채널정보요청4. BS또는 AP는 UT의예상채널정보를획득하기위하여HIS에위치정보전송5. HIS는전송된위치정보를바탕으로예상채널정보를 UT에전송

15[5] WINNER, “ D4.3: Identification and definition of cooperation schemes between RANs –final deliverable” IST-2003-507581 WINNER, Jun., 2005

핸드오버핸드오버 관련관련 정보정보 측정측정 기술기술::IEEE 802.16eIEEE 802.16e의의 ScanningScanning

핸드오버에적합한인접기지국을결정하기위하여 serving BS와 neighbor BS의신호측정

16

BS #1 (Serving)MS BS #2

(Target)BS #3

(Target)

MOB_NBR-ADV(N_NEIGHBORS =2)

MOB_SCN-REQ(Scan duration = N frames, Interleaving interval = P

frames, Iteration= 2 times)MOB_SCN-RSP

(start frame = M frames, duration = N frames)

Synchronize with BS #2, measure metrics

M frames


Non-scanning interleaving Interval (P frames)



Scanning Interval

duration = N frames

Scanning Interval

duration = N frames

Data Traffic (if any)

Scanning request by MS

Scanning procedure

[6] IEEE Std 802.16e-2005, Part 16: Air Interface for Fixed and Mobile Broad-band Wireless Access Systems, Feb. 2006

핸드오버핸드오버 관련관련 정보정보 측정측정 기술기술::IEEE 802.16eIEEE 802.16e의의 ScanningScanning

Scanning 동안예상기지국과정보교환Ranging parameter(power offset, CDMA code, etc.)과 Basic service capability 정보획득

Association levelLevel 0: Scan / Association without coordination

Contention based ranging Level 1: Association with coordination

Unicast ranging인접기지국에서유효한 CDMA ranging code와 transmission opportunity(Rendezvous time) 전송

Level 2: Network assisted association reportingMulticast ranging인접기지국에게유효한 CDMA ranging code코드만 할당받음Ranging 구간은 serving BS에게부여받음

17

핸드오버핸드오버 관련관련 정보정보 측정측정 기술기술::IEEE 802.16eIEEE 802.16e의의 AssociationAssociation

18

BS #1(Serving)MS BS #2

(Target)BS #3

(Target)

MOB_NBR-ADV (N_NEIGHBORS =2)

MOB_SCN-REQ(duration = N frames, Association level)

MOB_SCN-RSP(start frame = M frames, duration = N frames,

Association parameter)


M frames


Scanning Interval duration

= N frames

RNG-REQ(Association : Initial ranging)

RNG-RSP(Ranging parameter, service level)

Scanning request by MS

RNG-REQ(Association : Initial ranging)

RNG-RSP(Ranging parameter, service level)

Scanning with Association procedure


트리거트리거 (Trigger)(Trigger)

측정된정보를기반으로핸드오버알고리즘에특정한행동을취하도록명령하는것측정된링크품질이임계값이하일경우 스케닝, 핸드오버시작

WINNER 프로젝트의 L2 트리거물리적인정보를기반으로한트리거

신호세기, 간섭수준, BER/PER(Packet Error Rate)서비스측면에서알고리즘에의한트리거

QoS violation, CAC&CF(Connection Admission Control & Connection Forwarding), 위치, 이동속도, 사전정보, 서비스가능유무

19

MOB_BSHO_REQ(Recommended BS=BS#2, BS#3)(BS#2 service level prediction =2)(BS#3 service level prediction =2)

(Resource Remain Type = MS resource retain)

HO-pre-notification(MS identifier, connection parameters,

capabilities, required BW and QoS )

트리거트리거(Trigger):(Trigger):IEEE 802.16eIEEE 802.16e의의 핸드오버핸드오버 초기화초기화 과정과정

20


(Target)BS #3

(Target)

MOB_MSHO_REQ(Recommended BS = BS#2, BS#3)

(Neighbor BS#2 : CINR = v1)(Neighbor BS#3 : CINR = v2)

HO-confirm

HO-pre-notification(MS identifier, connection parameters, capabilities, required BW and QoS )HO-pre-notification-response

(Ack, lower QoS class)HO-pre-notification-response

(Ack, lower QoS class)

MOB_MSHO_RSP(BS_ID = BS#3)


capabilities, required BW and QoS )HO-pre-notification

(MS identifier, connection parameters, capabilities, required BW and QoS )HO-pre-notification-response

(Ack, lower QoS class)HO-pre-notification-response

(Ack, lower QoS class)

Handover initiation

by MS request

Handover initiation

by BS request


핸드오버핸드오버 결정결정 (Decision)(Decision)

핸드오버결정요인수평적핸드오버

신호품질및망내자원상황

수직적핸드오버

망내부하, 서비스가격, 지원가능한통신속도, 보안, 이동속도및전력소모

WINNER 프로젝트의핸드오버결정Handover initiation

Signal strength, cell load, user preference, etc.Handover decision

Signal strength, cell load, user preference, etc.

IEEE 802.16eMS initiated & decision, BS initiated & BS decisionSignal strength, cell load, QoS level

21

MOB_HO_IndicaitonDecision to cancel

handover

핸드오버핸드오버 결정결정::IEEE 802.16eIEEE 802.16e의의 핸드오버핸드오버 결정결정

22


(Target)BS #3

(Target)





HO-confirm

HO-pre-notification(MS identifier, connection parameters, capabilities, required BW and QoS )

HO-pre-notification-response(Ack, lower QoS class)



MOB_HO_Indicaiton(Time=L frames)

Release of MS

Decision to execute handover

Downlink traffic


핸드오버핸드오버 수행수행

Serving BS와의연결을종료하고 target BS와의무선링크를재설정하는과정

Seamless handover끊어짐없는핸드오버를제공하기위해서는서비스별로정의된지연한계이내에핸드오버수행을완료해야함

23

Application

Conversational voice

Video phone

Telemetry

Interactive games

Telnet

One-way delay

<150 msec preferred, <400 msec limit

<150 msec preferred, <400 msec limit

< 250 msec

< 250 msec

< 250 msec

Voice messaging

Video phone

< 1 sec for playback, < 2 sec for record

< 4 sec /page

핸드오버핸드오버 수행수행::IEEE 802.16eIEEE 802.16e의의 핸드오버핸드오버 수행수행

핸드오버수행절차Down link synchronization하향채널동기, preamble detection

DL-MAP/ UL-MAP detection하향링크주파수조정

RangingCID(Connection ID) 할당, 상향링크 frequency/uplink power/time 조정

Ranging 방안물리계층에따라달라짐

Time slot으로구분(OFDM, SC(Single Carrier), SCa PHY)Time slot과 CDMA code로구분 (OFDMA PHY)

접근방안

경쟁기반접근방안

비경쟁기반접근방안24

핸드오버핸드오버 수행수행::IEEE 802.16eIEEE 802.16e의의 핸드오버핸드오버 수행수행

25

MS BS #2(Target)

Fast Ranging_IE(UL_MAP)

RNG-REQ(MS MAC address, Serving BS_ID, Raging Purpose Indication, HMAC/CMAC)

RNG-RSP(MS MAC address, Basic CID, Primary CID, HO Process Optimization, CID Update, CMAC)

Complete Initial Network Entry (after handover)

UL-MAP IE()BR Header

Downlink traffic

UL_MAP : CDMA Allocation IE()

RNG-REQ(MS MAC address, Serving BS_ID, Raging Purpose Indication, HMAC/CMAC)

RNG-RSP(MS MAC address, Basic CID, Primary CID, HO Process Optimization, CID Update, CMAC)


UL-MAP IE() : CDMA Allocation IE()

BR Header

Downlink traffic

CDMA Code for Handover RangingRNG-RSP

(Raging status = Success)

CDMA Code for BR

OFDM PHY

Non-contention based ranging

Using Fast ranging IE() when scanning has done with association

OFDMA PHY

Contention based ranging

Without association


IEEE 802.16eIEEE 802.16e의의 22계층계층 핸드오버핸드오버 과정과정

Initiated by MS request

26


(Target)BS #3

(Target)





HO-confirm

Fast Rainging_IE(UL_MAP)

RNG-REQ

HO-pre-notification(MS identifier, connection parameters, capabilities, required BW and QoS )




MOB_HO_Indicaiton(Time=L frames)

Release of MS

RNG-RSP


Initiation

Decision

Execution


연구배경IEEE 802.16e 와같은 TDD OFDMA 에서는셀내의MS의위치와분포에따라 Uplink와 Downlink의채널품질이다를수있음주기적인 Scanning으로인한통신두절이있음

특징주기적인 Scanning 구간대신핸드오버요청시에만주변기지국의신호를측정

핸드오버결정요인으로 Uplink와 Downlink를모두고려

상향링크상향링크 정보를정보를 이용한이용한 핸드오버핸드오버

MS BS#1(Serving)

BS#2(Target)

BS#3(Target)

Th1 : Uplink 를 고려한핸드오버결정임계값Th2 :AMC 유저를위한핸드오버임계값Th3 : 상향링크를고려한 핸드오버대상기지국결정임계값 (UL hysteresi사용)Th4 :통신을위한최소 Downlink 신호품질임계값Th5 : 하향링크를고려한 핸드오버대상기지국결정임계값 (UL hysteresi사용)Th6 : 통신을위한최소 Upnlink 신호품질임계값

(user ID, resource allocation informatio)

상향링크상향링크 정보를정보를 이용한이용한 핸드오버핸드오버 과정과정

Uplink 신호품질측정

Uplink 신호품질측정결과보고

Downlink 신호품질측정

Downlink 신호품질측정결고보고

Downlink와 Uplink를고려한핸드오버결정

43__ & THPTHPP DL_targetservingULtargetUL >>−

65__ & THPTHPP UL_targetservingDLtargetDL >>−

[7]S. H. Cho et al, “Hard handoff scheme exploiting using uplink and downlink signal in IEEE 802.16e system”, VTC 2006 Fall

2.52.5계층계층 이동성이동성 보장보장 기술기술

−−IEEE 802.21 Media Independent Handover (MIH)IEEE 802.21 Media Independent Handover (MIH)

29

30

IEEE 802.21 MIHIEEE 802.21 MIH

최적화된핸드오버를수행하기위하여필요한망에관련된정보와무선링크의정보의제공

2계층이동성관리기술의정보와상위계층이동성관리기술의연동

MIH 제공서비스Event servicesCommand servicesInformation services

< MIH 프로토콜스택>

[8]IEEE 802.21/D03.00, “Draft IEEE Standard for Local and Metropolitan Area Networks: Media Independent Handover Services”, December 2006

IEEE 802.21 MIH:IEEE 802.21 MIH:Multiple Access Network Reference ModelMultiple Access Network Reference Model

MIH provides convergence of link-layer state information from multiple heterogeneous access technologies

Supported by existing SAP in IEEE 802.xNot exist SAP for MIH in 3GPP/3GPP2

MIH defines MIH_3GLINK_SAP to use MIH for 3GPP/3GPP2

31- LSAP : Link Service Access Point - LLC : Link Layer Control -SAP : Service Access Point -MLME : MAC Layer Management Entity - PLME : Physical Layer Management Entity - CS : Convergence Sublayer

32

IEEE 802.21 MIH: IEEE 802.21 MIH: MIH ServicesMIH Services

Media independent event services하위계층의상태변화를상위계층에알리는역할수행이벤트생성위치에따른분류

Remote event : 다른망요소에서생성된이벤트Local event : 동일한망요소에서생성된이벤트

이벤트 인식위치에따른분류Link event : PHY, MAC MIHMIH event : MIH L3+

이벤트내용에따른분류MAC/PHY 상태변화이벤트

MAC또는 PHY 계층의상태변화링크파라미터이벤트링크계층파라미터의변화

예측이벤트과거와현재의조건을기반으로링크의변화예측정보알림

링크동기이벤트링크계층동작에관한정보알림

링크전송이벤트링크계층에서상위계층 PDU의전송상태알림

33

IEEE 802.21 MIH: IEEE 802.21 MIH: MIH ServicesMIH Services

Media independent command service링크의상태를결정하고다중모드단말을제어명령생성위치에따른분류

Remote command : 다른망요소에서생성된명령Local command : 동일한망요소에서생성된명령

명령인식위치에따른분류MIH event : L3+ MIHLink event : MIH PHY, MAC

Media independent information service핸드오버에필요한정보를획득하기위하여사용됨

Neighbor map, link layer information, availability of service

Type0x0 : Core MIH specific IEs0x2 : Vender specific IEs0x3 : Working group specific IEs


−−Fast Mobile IPv6 (FMIPv6)Fast Mobile IPv6 (FMIPv6)−−Hierarchical MIPv6 (HMIPv6)Hierarchical MIPv6 (HMIPv6)−−Proxy Mobile IPv6 (PMIPv6)Proxy Mobile IPv6 (PMIPv6)

34

Fast Mobile IPv6 (FMIPv6)Fast Mobile IPv6 (FMIPv6)

설계목적경로최적화를통한망효율성향상

핸드오버에의한패킷손실감소

Binding Update에의한핸드오버지연감소

특징new PoA의발견시 old PoA를통한 binding update

L3 핸드오버이전에 old PoA에서미전송된패킷을터널링시킴패킷손실감소

핸드오버동안터널링된패킷수신 핸드오버지연감소

CoA관리를 CN(Corresponding Node)이수행HA(Home Agent)를경유하지않음 경로최적화

MN가현재의 AR에 L2 연결을유지하고있는동안에 L3 핸드오버수행

CoA 등MN에대한정보를미리공유AR 정보교환프로토콜이필요

35[9] R. Koodli,“ Fast Handovers for Mobile IPv6,“ RFC4068, Jul.,2005

Fast Mobile IPv6 (FMIPv6):Fast Mobile IPv6 (FMIPv6):동작동작 절차절차

36

0. Movement 7. Movement

1. RtSolPr

2. PrRtAdv

3. FBU

4. HI

5. HAck

6. FBAck

8. FNA

9. BU

MN MNMN

AP AP

PAR NAR

CN

-RtSolPr : Router Solicitation for Proxy Advertisement -PrRtAdv : Proxy Router Advertisement -FBU : Fast Binding Update- HI : Handover Initiate -Hack : Handover Acknowledge -FBAck : Fast Binding Acknowledgment -FNA : Fast Neighbor Advertisement -BU : Binding Update

Hierarchical MIPv6 (HMIPv6)Hierarchical MIPv6 (HMIPv6)

설계목적MIPv6 에서잦은핸드오버시MN과 HA, CN 사이에발생하는Binding update의부하를줄이기위함

특징망을계층 구조로관리

상위MAP의변경에따른 RCoA의변경필요시에만 HA와 CN에게Binding update

MAP(Mobility Anchor Point)Local HA(Home Agent) 의역할

RCoA (Regional Care-of-Address)최상위층의MAP에따라결정되며 HA에등록되는 CoA

LCoA(On-link Care-of-Address)같은MAP의네트워크안에서구별가능한 CoA

37[10] H. Soliman, C. Castelluccia, K. El Malki and L. Bellier, “Hierarchical Mobile IPv6 Mobility Management (HMIPv6)”, RFC 4140, August 2005

Hierarchical MIPv6 (HMIPv6):Hierarchical MIPv6 (HMIPv6):동작동작 절차절차

38

MAP1

AR2

MAP2

AR3

CN

AR1 AR4

1. Router Advertisements2. Binding Update(RCoA1 RCoA1)(LCoA1 LCoA2)

HA

0. Movement 4. Movement

Care- of-Address(RCoA1)(LCoA1 )

3. Binding Update Acknowledg


5. Router Advertisements


6. Binding Update(RCoA1 RCoA2)(LCoA2 LCoA3)

7. Binding Update Acknowledg

MN

Proxy Mobile IPv6 (PMIPv6)Proxy Mobile IPv6 (PMIPv6)

설계목적IPv6 지원망에서단말이이동관련시그날에관련하지않고이동성을제공하기위함

특징네트워크기반Mobile IPIP mobility 에의한단말의변화없음Tunneling overhead 감소MN과 HA,CN 간의 Binding Update overhead감소Mobile IPv6의재사용실제구현및설치에용의함

위치정보보안강화

MN-HoA(Home-of-Address)를유지하여위치추적이쉽지않음

39[11]S. Gundavelli, K. Leung, V. Devarapalli, K. Chowdhury and B. patil, “Proxy Mobile IPv6”, draft-ietf-netlmm-proxymip6-00.txt, April 8, 2007

Proxy MIPv6 (PMIPv6):Proxy MIPv6 (PMIPv6):동작동작 절차절차

40

MN

MAG2

AAA-server

CN

MAG1

LMA

1. Router Solicitation

0. Movement

2. AAA Query

3. AAA Reply

4. Router Advertisement

IP addressconfiguration

(MN-HoA)

5. Proxy BU

6. Proxy BU ACK

Update Binding cacheEntry for the MN

-Proxy BU : Proxy Binding - Proxy BU ACK : Proxy Binding Acknowledge-AAA : Authentication Authorization Accounting


−−SIPSIP−−Application layer handoverApplication layer handover

41

SIP(Session Initiation Protocol)SIP(Session Initiation Protocol)

IETF에서세션(session)을관리하기위하여정의응용계층프로토콜

Initiation, management, termination of sessions across packet network

re-INVITE를사용한이동성보장기술에참여가능SDP (Session Description Protocol)세션에관련된보다자세한정보를관리

Session name and purposeTimes the session is activeMedia to useInformation where to send and receive mediaContact information

42

<reference>

SIP(Session Initiation Protocol)SIP(Session Initiation Protocol): Session initiation procedure: Session initiation procedure

43

MN MNMN

AP AP

Proxy Server Proxy Server

Location/RedirectServer

Proxy Server User Agent

1. IN

VIT

E

1. INVITE

1. INVITE

1. INVITE

2. 302

(Moved

Temporaril

y)

1. INVITE

3. ACK

2. 302(Moved

Temporarily)

3. ACK 4. 180(Ringing)200(OK)

4. 180(Ringing)

200(OK)

4. 1

80(R

ingi

ng)

200(

OK

)

3. A

CK

3. ACK

3. ACK

5.re-INVITE

5.re

-IN

VIT

E

5.re-INVITE

6. 1

80(R

ingi

ng)

200(

OK

)6.

180

(Rin

ging

)20

0(O

K)

6. ACK

6. ACK

Application layer handoverApplication layer handover

핸드오버지연을최소화시키기위하여망의도움없이다중경로/다중세션기술을사용하여접속망을 변경하는과정

배경Coexistence향후통신서비스는 CDMA2000, UMTS, WiBro, WLAN 등의다양한무선통신망이상호공존할것으로예상됨

Multi-interface support하나의MN이여러개의 RAT를사용함각 RAT는독립된 interface를가짐MN은 multi-homing 기술을지원함

44UMTS : Universal Mobile Telecommunication System

Application layer handover:Application layer handover:Reference ArchitectureReference Architecture

45

Application program/user interface

RTP/RTCP SIP

TCPUDP

IPv4, IPv6, MIP, HIP

MIH

Handover Decision

WINNER UMTS WLAN

Application

Transport

Network

Link

Physical

SDP

①① Handover policy of user(cost

plan, service plan)

② Information of service flows(type, format, transport protocol, IP addresses for send/receiver, port number)

③ Information about active RAT and candidate RAT

④ Sequence information for the TCP service flow

⑤ Time stamp information for the UDP service flow

⑥ Control for the handover service flow during Inter-RAT handover

⑦ Handover management (Handover preparation, Handover execution RAT selection)

②

③④

⑤

⑥

⑦

InformationControl

UDP service flowTCP service flow

46

Application layer handover:Application layer handover:Handover Decision ModuleHandover Decision Module

Handover decision module의기능

Handover decision

Information Management

QoS Management

Sequence Management

Handover Management

From User interfaceHandover policy of user

From MIHAvailable RAT information

User preferenceRAT information

QoS monitoringinformation

Handover control(Measurement, Modem on/off, Link setup, Registration request)

Session Duplicate Request

From SDP,SIPService flow information

Service flow information

Session control(Session generation, termination)

Control

Multi session identifyFlow 1 Flow 2

Concatenated Flow

User

Application layer handover:Application layer handover:Handover Decision ModuleHandover Decision Module의의세부세부기능기능

47

척도

서비스품질

관리

서비스품질

관리

시퀀스관리

핸드오버

관리

세부기능 역할

• 서비스플로우정보관리• 사용자 RAT 선호도관리

• RAT관련정보관리

• SIP, SDP, 서비스클래스를통한세션정보관리

• 사용자가입력한 RAT 선호정보관리

• 사용가능한 RAT의무선정보관리

• 서비스플로우요구자원관리

• 서비스플로우 QoS 파라미터관리

• 서비스 플로우가 요구하는 QoS를 만족시키기 위하여필요한자원을관리

• 현재 설정된 서비스 플로우와 관련된 QoS 파라미터관리

• 핸드오버서비스플로우설정관리• 다중경로서비스플로우결합관리• TCP 서비스플로우시퀀스관리

• UDP 서비스플로우 time stamp 관리

• 다중경로서비스플로우설정을위한동작수행• 다중경로로전송된동일한서비스플로우의인지• TCP시퀀스정보를이용하여서비스플로우결합

• UDP/RTP time stamp정보를 통한 서비스 플로우 결합

• 핸드오버초기화제어• 핸드오버수행접속망선택• 핸드오버완료제어

• RAT선호도/ RAT 관련정보를고려한무선링크설정

• QoS를만족시킬수있는접속망 선택

• 다중경로서비스플로우의해제관리

Application layer handover:Application layer handover:ConceptConcept

48

RAN 1 RAN 2

MN

Signal Qualityfor RAN 1 Signal Quality

for RAN 2

Measurement triggerMIH Handover magt.

GW GW

Service flow

Handover init. triggerMIH Handover magt.

MeasurementLink setup

Handover decision triggerMIH Handover magt.

Session request

Session Request

Service flow

RAN2 modem up

Flow 1Flow 2

Service

수직수직 핸드오버핸드오버 기술기술

−−수직수직핸드오버핸드오버정의정의및및분류분류

−−수직수직핸드오버핸드오버요구요구기술기술

−−Coupling methodCoupling method−−Radio Resource ManagementRadio Resource Management−−WINNER Cooperation mechanismWINNER Cooperation mechanism

49

수직수직 핸드오버핸드오버 정의정의 및및 분류분류

Vertical handoverInter-system handover between two different radio systems on different layers of the overlay structure Two type of vertical handover

Downward vertical handoverHandover to a cell of smaller size

Upward vertical handoverHandover to a cell of larger size

50

수직수직 핸드오버핸드오버 요구요구 기술기술

Coupling Method이종접속망간의결합방안으로다음사항을고려

표준의수정정도

상호연동의끊어짐정도

공통망요소의정도

Tight couplingEach network shares same core network

Loosely couplingEach network has individual core networkConnected by gateway

51

수직수직 핸드오버핸드오버 요구요구 기술기술

Radio Resource Management (RRM)망자원을효과적으로사용하기위하여요구되는기술

Admission control : 혼잡을예방하기위한기술Load/congestion control : 혼잡을해결하기위한기술QoS management : 서비스품질관리기술

Combined RRMResources are allocated centrally for all involved RATs by a single entityEx) Common RRM, Joint RRM

Concurrent RRMResources are allocated within each RAT by a local entity in a distributed manner

52

Coupling MethodCoupling Method

Tight coupling vs. Loosely coupling

53

Tight Coupling Loose Coupling Open Coupling망활용성

운영비용

성능

기술적어려움

별도의 망설치필요없음 별도의망설치필요

망운영비용이저렴 망운영비용증가

수직핸드오버성능증가 수직핸드오버성능감소

새로운망을추가하는것이어려움 새로운망의추가가용이

Radio Resource Management:Radio Resource Management:Common RRMCommon RRM

Proposed by UTRAN and GERAN in 3GPPSupport the cooperation between UMTS and GSM/GPRSTwo component (same layer)

CRRMBe responsible for coordinating a certain number of RRM entities

RRM Be responsible for the allocation inside one radio resource pool

54

Radio Resource Management:Radio Resource Management:Joint RRMJoint RRM

Proposed by TRUST and SCOUTSupport the cooperation between HyperLan2 and UMTSConsist of the mechanism and the architecture for heterogeneous UT in B3G

55

TRUST : Transparently Reconfigurable Ubiquitous TerminalSCOUT : Smart User-Centric Communication Environment

Radio Resource Management:Radio Resource Management:Layered RRMLayered RRM

Proposed by WINNER projectConsider multi-technology / multi-domain concepts

56

57

WINNER Cooperation mechanismWINNER Cooperation mechanism

Partially Centralized Approach Loose coupling or Open couplingExploit the installed base of wireless systemAllow the gradual introduction of WINNER network


CoopRRMPlaced in ACS or ARHave interfaces with other CoopRRM of the same or different operators

Specific RRM (SRRM)Work in a distributed mannerCoordinated by the CoopRRM entity

58

59


Mobility ManagementSupport the inter-system handover for traffic balancing strategy

Decision criteria Coverage criteria, Traffic load, User/operator preference, etc.

Admission ControlEnsure that the admittance of a new flow or handover flow does not violate the service commitments made by the network to already admitted flows

In case of limited resourcesReduce requests for connection/flow in question and/or for lowerpriority flowsResource re-partitioningHandover flows (cell/mode/RAN)

60


Congestion/Load ControlEnsure that the system is in stable stateInteract with the service level controller

In case of limited resourcesReduction of requests for flowsAttainment of more resources by resource re-partitioning in neighbouring cellsHandover of flows to another cell/mode/RAN

QoS ManagementLayered scheduling

The scheduler 2 Coarse scheduler Be located at the CoopRRM entity

The scheduler 1Intelligent schedulerBe placed at the Access Point/RelayTake care of dynamic link adaptation

ReferenceReference

[1] J. Maner, and M. Kojo,“Mobility related Terminology,“ RFC3753, Jun., 2004[2] WINNER, “D4.1: Identification and definition of cooperation schemes between

RANs “, internal deliverable, IST-2003-507581 WINNER, Jun., 2004.[3] IEEE P802.21™/D01.00, “IEEE P802.21/D01.00 Draft IEEE Standard for Local and

Metropolitan Area Networks: Media Independent Handover Services,” Mar., 2006.[4] N. Nasser, A. Hasswa and H. Hassanein, “Handoffs in Fourth Generation

Heterogeneous Networks” IEEE Commun. Mag., vol. 44, no. 10, Oct. 2006, pp. 96-103.

[5] WINNER, “ D4.3: Identification and definition of cooperation schemes between RANs –final deliverable” IST-2003-507581 WINNER, Jun., 2005


[7] S. H. Cho et al, “Hard handoff scheme exploiting using uplink and downlink signal in IEEE 802.16e system”, VTC 2006 Fall

[8] IEEE 802.21/D03.00, “Draft IEEE Standard for Local and Metropolitan Area Networks: Media Independent Handover Services”, December 2006

[9] R. Koodli,“ Fast Handovers for Mobile IPv6,“ RFC4068, Jul.,2005[10] H. Soliman, C. Castelluccia, K. El Malki and L. Bellier, “Hierarchical Mobile IPv6

Mobility Management (HMIPv6)”, RFC 4140, August 2005 [11] S. Gundavelli, K. Leung, V. Devarapalli, K. Chowdhury and B. patil, “Proxy Mobile

IPv6”, draft-ietf-netlmm-proxymip6-00.txt, April 8, 200761

seamless services in vertical handover -...

Documents