이기종무선망간 Handover 기술 2007. 2. 5. (v0.8) SK telecom, Access 기술연구원 김현욱 1
I. 이기종무선망 HO 개요 2
종류 은 3GPP, 3GPP2, IEEE 에서 I-WLAN, GAN, VCC, MIH 등 4가지방식이있음 Solution 표준화목적현황주요업체 I-WLAN (Interworking WLAN) 3GPP 3GPP(3GPP2) 와 WLAN 간의 Interworking을위한방안으로고안되었음 과금통합등초기단계는정의되었음 Seamless Handover 등은 GAN 또는IMS 방식과통합되고있음 GAN 3GPP GSM 과 WLAN 간의 Handover 를지원하기위한 UMA solution 을 3GPP 규격에통합한규격임 3GPP R6 에서규격완료됨 GSM/GPRS 용제품은출시되고있으며, WCDMA 제품은출시예상됨 Kineto wireless Alcatel Nokia VCC (with IMS) 3GPP CS domain 과 PS domain 의이동성을보장하기위한 IMS 기반솔루션 3GPP R7 에서규격정의중 ( 08 년이후에나상용화가능예상 ) 초기 VCC 규격으로상용화제품을출시하려는움직임활발함 Nortel, UTStarcom Bridgeport Cicero, FirstHand LongBoard 등 IEEE 802.21 (MIH) IEEE IP 기반의다양한무선기술간의 Seamless Handover를지원하기위한기술로, 하위계층의정보를이용하여효율성및확장성을강화한기술임 IMS 또는 GAN 을보완하는기술 (HO 성능개선 ) 현재 Draft 규격상태이며, 07 년중반규격완료예상 InterDigital Intel Motorola Samsung, ETRI 등 3
3GPP, I-WLAN Network Architecture 3GPP 에서 I-WLAN 은 handover 보다는인증, 과금등 customer management와 관련된사항으로표준화진행중 Intranet / Internet 3GPP Visited Network WLAN UE Ww WLAN Access Network Wn WAG Wa Wg 3GPP AAA Proxy Wf Offline Charging System Wd Wu WLA AN 3GPP IP Ac ccess Wp Packet Data Gateway Wi Wm Wy 3GPP AAA Server Wz Wo OCS 3GPP Home Network Dw D' / Gr' Wf Wx SLF HSS HLR Offline Charging System 4
3GPP2, I-WLAN Network Architecture 3GPP2 에서 I-WLAN 에대하여 high level specification 만정의된상태이고, 특이점은일종의중계시스템 (broker system) 을사용함 cdma2000 System One or more cdma2000 Home Networks that may be administered by the same or different entity cdma2000- Broker Interworking cdma2000 Broker System Broker-WLAN interworking cdma2000-wlan interworking WLAN System One or more WLANs networks One or more Broker networks that serve one or more cdma2000 Systems and one or more WLAN systems. A Broker System enables Inter-System roaming, where the cdma2000/ WLAN Systems are administered i dby different entities. i Mobile Station (MS) 5
Generic Access Network Cellular 망과 UMAN 간 Seamless한서비스제공받을수있도록함 음성 + 데이터세션모두에서셀룰라와고정 IP 망사이의핸드오버가가능 3GPP에채택 ( 05.4, TS43.318), Generic Access to A/Gb Interfaces BT Fusion ( 05.9 ~) 서비스제공, 약 10만가입자확보 ( 07.2월기준 ) 그외 Telia Sonera (Home Free), Telecom Italia (Unica) 등서비스제공 Cellular l Access Network UMA enabled dual mode handset Private Network IP Access Network BSC GANC (UNC) Mobile Core Network Generic Access Network 6
UMA(Unlicensed Mobile Access) Unlicensed Mobile Access (UMA) was originally developed by the UMA Forum founded by Kineto and leading cellular companies http://www.umatechnology.org/ The purpose of UMA is to allow seamless mobility between unlicensed technologies (WLAN, Bluetooth, etc.) and licensed cellular technologies UMA was adopted by 3GPP R6 in April 2005 - In 3GPP, UMA renamed Generic Access Network (GAN) - Initially, GAN only supported WLAN to GSM/GPRS handovers - Lately, CR s have been written to also support WCDMA handovers 7
System Architecture for GAN GSM/GPRS CDMA 8
System Arch. For Voice Call Continuity A/Iu VCC UE Gm VMSC CAP P-CSCF IP Multimedia PLMN/ Networks PSTN gsm SCF V3 ISUP Unspecified interface GMSC CAMEL Service Domain Selection Function Sh VCC Application ISUP CS Adaptation Function Domain Transfer Function Sh HSS Ma Ma ISC ISC ISC MGCF Mg I-CSCF Mw S-CSCF Cx Mw PLMN/ PSTN 3GPP 에서정의하는 VCC 는 CS의 MAP과 PS의 IMS 기반호처리수행 9
CS call origination from the VCC user UE-CS UE-IMS VMSC MGCF I-CSCF S-CSCF gsmscf CAMEL Svc VCC Application CSAF DTF 1. Setup (B-Party DN) 2. IDP ( ) 3.Rerouting to IMS Determination 4. Connect ( IMRN ) 5. IAM ( IMRN ) 6. INVITE ( IMRN ) 7a1. INVITE ( IMRN ) 7b. INVITE ( IMRN ) 7a2. INVITE ( IMRN ) 8.CS-Origingation processing 9.Session Anchoring 10. INVITE ( B-Party DN ) 11. Service Control Logic 10
Signal Path Between VCC UE and IMS UE 11
II. IEEE802.21(MIH) 21(MIH) 기술 12
MIH Positions VCC 3GPP/2 I-WLAN SAE-LTE Inter-working & Handover Signaling IEEE 802.21 802.11r 802.16e IEEE Horizontal Handovers NETLMM MIP SIP DNA HIP IETF FMIP MIPSHOP IP Mobility & Handover Signaling Provides 802 component to other Handover Standards d 13
Standard Services (Entities or APIs) 14
MIH Network and Terminal Architecture Events Events Events Events E/C/I L LC IS/CS/ES 15
MIH Convergence Function 802.21 Users Mobility Policy Mobile IP Other Mobility Protocols 802.21 Events 802.21 Commands 802.21 Information 802.21 Convergence Function (MIHF) Information flow is bi-directional Events flow from lower layers to upper layers Commands flow from upper to lower layers Cellular Link 802.11 Link 802.x Link 16
MIH Scope Handover Handover Handover Initiation Preparation Execution Scope of 802.21 Search New Link Setup New Link Transfer Connection Network Discovery Layer 2 Connectivity it Network Selection IP Connectivity Handover Negotiation Handover Signaling Context Transfer Packet Reception IEEE 802.21 helps with Handover Initiation, Network Selection and Interface Activation 17
Key Functionality for MIH Applications (VoIP/RTP) Connection Handover Management Policy Handover Management Mobility Management Protocols IE ETF Link Layer Triggers State Change Predictive Network Initiated 802.21 MIH Function Smart Handover Information Ti Triggers Messages Service L2 Triggers Handover Information and Events Messages Service WLAN Cellular WMAN IEEE 802.2 1 Handover Commands Client Initiated Network Initiated Vertical Handovers Network Information Available Networks Neighbor Maps Network Services Protocol and Device Hardware 802.2121 uses multiple services to Optimize Vertical Handovers 18
MxN Mixed-Network Client Use Case Operating on 3G WWAN Zone 1 Zone 2 3G WWAN Zone 3 Wakeup Wi-Fi Plug into power jack Wakeup Wi-Fi Continue over Wi-Fi Zone 4 Zone 5 Zone 6 Airport Wi-Fi Link Going Down. Radio State t 3G WWAN Connect to Wi-Fi Continue session on Wi-Fi Home Operator initiated switch to WiMAX Continue session on WiMAX Shutdown Wi-Fi Continue session on 3G WWAN Battery level low Shutdown WiMAX Switch to 3G WWAN Wi-Fi WiMAX GPS Zone 7 WiMAX Zone 8 WiMAX Zone 9 IEEE 21 21 802.21, SIP, IEEE VCC, 802.21 IMS, for for Network Network it it Discovery Selection and Service 802.21, VCC, SIP, SIP, IMS IMS for for Call Service Continuity Continuity (3G (Wi-Fi WWAN WiMAX) Wi-Fi) Continuity across multiple radios (3G WWAN Wi-Fi WiMAX) 19
Ex #1 : Network Detection 20
Ex #2 : HO Initiation and Preparation Home MIH Multi-Mode M Terminal (MMT) WLAN AN WiBro AN POS MIH user L3 (MIP)(DM) MIH (AM) WLAN MAC WiBro MAC AP MIHF (WLAN POA) Old AR MIIS Server RAS MIHF (WiBro POA) New ACR MIH_Handover_Initiate.request MIH_Handover_Initiate REQUEST FRAME MIH_Handover_Initiate RESPONSE FRAME MIH_Handover_Initiate.response MIH_Handover_Prepare REQUEST FRAME MIH_Handover_Prepare RESPONSE FRAME Decision to handover from WLAN to WMAN MIH_Switch.request C-NEM-REQ (ranging) RNG_REQ Handov ver Initiation and P reparation C-NEM-RSP (ranging) M-NEM-REQ (register) RNG_RSP SBC_REQ SBC_RSP Authentication & Key Exchange REG_REQ MIH_Link_UP.indication Link_Up.indication REG_RSPRSP DHCP Link_Handover_Complete. indication MIH_Switch.response DSA_REQ DSA_RSP 21
Ex #3 : Handover Execution Handove Execution r n 22
III. MIH + SIP Approach 23
Protocol Layering for MIH Typical Examples of Mobility Protocols SIP User or session mobility between different terminals Application 7 Presentation 6 Session 5 Mobile IP Terminal mobility across IP networks 802.2121 Cross layer support for terminal mobility when moving across different technologies Transport Network Data Link Physical 4 3 2 1 24
MIH Client and Server WCDMA FA P-CSCF IMS PBNA Node-B RNC SGSN GGSN Dual-Mode Terminal FA BcN MIH Server RAS ACR WiBro Edge Router AAA MIP HA DHCP/ DNS Internet 25
MIH Message Transmission IP Packet UDP Datagram MIH Message (MIHF Frame Format-IEEE 802.21) a newly defined port number Lower layer(l1, L2) : MIH IP layer : Mobile IP 관련 server discovery 과 managing : SIP 26
Authentication Examples Two authenticators belong to the sa me AAA domains The handover can be intra-technol ogy or inter-technology Home AAA domain AAA server MN would need to run EAP all the wa y to the home AAA server Alternatively visited domain s AA A server may yperform authenticati on if it has MN s credentials trans ferred from the home AAA server EAP may performed either proacti vely or reactively Authenticator1 WiFi, WiMAX and/or Cellular AP/ AP/ BS BS AAA domain 2 AAA server MN Authenticator2 WiFi, WiMAX and/or Cellular AP/ BS AP/ BS 27
Handover Failure Case Mobile Node Serving Network Other Network Candidate Network 1 Candidate Network n Other Network UP Entity MIH User MIHF MAC-S MAC-C PoA-S PoS-S MIH User MIIS Server PoA-C1 PoS-C1 MIH User PoA-Cn PoS-Cn MIH User UP Entity Traffic flow between MN and Serving Network Handover decision made and candidate network discovered MIH_Net_HO_Candidate_Query.request MIH_Net_HO_Candidate_Query Request MIH_Net_HO_Candidate_Query.indication MIH_N2N_HO_Query_Resources.request MIH_N2N_HO_Query_Resources Request MIH_N2N_HO_Query_Resources Response MIH_N2N_HO_Query_Resources.confirm MIH_ Net_ HO_ Candidate_ Query.response MIH_Net_HO_Candidate_Query Response (HandoverAck=1: Initiate Handover) MIH_Net_HO_Candidate_Query.confirm MIH_MN_HO_Candidate_Commit.request MIH_MN_HO_Candidate_Commit MN HO C it Request MIH_MN_HO_Candidate_commit.indication MIH_MN_HO_Candidate_Commit.confirm MIH_MN_HO_Candidate_Commit Request MIH_MN_HO_Candidate_Commit Response MIH_MN_HO_Candidate_Commit MN HO Commit Response (HandoverStatus=0: Abort Handover) MIH_MN_HO_Candidate_Commit.confirm Handover failed and intitiate another handover 28
QoS Mapping Between Different Radios QoS Class Applications Data Delivery Services QoS Parameters Scheduling Services Packet Scheduling Discipline/Algorithm Hard QoS -T1/E1 -VoIP without silence suppression UGS - Tolerated jitter - SDU size - Min. reserved traffic rate - Max. latency - Request/Transmission policy - Unsolicited grant interval UGS Round-robin (Periodic/fixed assignment) -VoIP with silence suppression - Streaming Video - Video Phone RT-VR - Maximum latency ertps Round-robin - Min. reserved traffic rate (Periodic/dynamic assignment) - Max. sustained traffic rate - Traffic priority - Request/Transmission policy RT-VR - Unsolicited polling Interval rtps Round-robin (Dynamic assignment with delay constraint) Soft QoS - FTP (Download) NRT-VR - Min. reserved traffic rate - Max. sustained traffic rate - Traffic priority - Request/Transmission policy nrtps Max C/I PF Scheduling - HTTP - Instant Messenger BE - Max. sustained traffic rate - Traffic priority - Request/Transmission policy BE 29