臺灣博碩士論文加值系統

B3G 網路結合了傳統電信網路(PSTN)、無線通訊(UMTS/GPRS)、網際網路(Internet)，以及佈建方便成本低廉的無線區域網路(WLAN)。其中WLAN 有著高頻寬及低成本的優勢，即使未能取代3G 的地位，仍具備了相當的互補性。本篇論文主要針對WLAN Telephony 網路，根據3GPP 所制定WLAN 的架構，探討Mobile Host (MH)做terminal mobility 的技術。對real-time 的service 而言，SIPMobility 是相當被看好的一個terminal mobility mechanism，但這需要MH 本身支援SIP Mobility，且SIP Mobility 在handover 的時間對real-time service 仍嫌太長，為此本論文參考CAMEL 的技術，從網路端偵測E2E Tunnel state 的變化，直接從網路端去觸發terminal mobility，並在VoWLAN 的架構中新增Mobility Server(MS)，以Third Party Call Control (3PCC)的方式從網路端直接重建session。使用這種方式不僅能使重建session 的時間提早，重建session 的流程也能簡化，MH也不需要做任何修改。為了讓Mobility Server 提供terminal mobility 的服務，在通話建立之時就要觸發Mobility Server，3GPP 提出了以iFC(initial Filter Criteria)的方式觸發SIP Application Server，但這也就是在通話尚未建立之時就要以Invite request 去觸發Mobility Server，而這也可能造成通話未建立的情形就讓Mobility Server 去提供terminal mobility service。為此我們提出rFC (response Filter Criteria)的作法，在回覆200 OK 時才去觸發Mobility Server，就能避免啟動不必要的服務。另外，用戶在通訊時移動可能發生換手交遞信息漏失問題(Handover MissingProblem)。Simultaneous Mobility Problem 是Handover Missing Problem 的一種特例，這會導致session 重建時間延長，為此我們透過Mobility Server 的協助，使遺失的message 能主動送給MH，Handover Missing Problem 就能解決。

B3G (beyond 3G) network is an integration of heterogeneous networks such as PSTN, UMTS/GPRS, Internet, and Wireless LAN (WLAN). Among these networks, WLAN provides the advantages of high bandwidth and low cost. Although WLAN can not fully replace 3G network, it's still quite complementary. This thesis focuses on WLAN Telephony networks based on 3GPP-WLAN interworking architecture and discusses the terminal mobility mechanisms on it. As for real-time service, SIP Mobility is an appropriate mechanism for terminal mobility, however, Mobile Host (MH) supporting SIP Mobility is needed, and the handover delay is too long. On account of these problems, this thesis refers to CAMEL concept to trigger terminal mobility service from network side by detecting E2E Tunnel state. We add Mobility Server (MS) in VoWLAN to re-establish session with 3PCC. Our mechanism can not only advance the time to re-establish session but also simplify the session re-establishing process. Furthermore, MH needs no modification to support our mechanism. In order to activate terminal mobility service, Mobility Server must be triggered during session setup. 3GPP proposes initial Filter Criteria (iFC) mechanism to trigger SIP Application Server (AS) by an initial request, but Mobility Server might be triggered while the session setup is not totally complete, and Mobility Server might provide terminal mobility service even when the session is not established. For this problem, we propose response Filter Criteria (rFC) mechanism to trigger Mobility Server by a 200 OK response, and this can prevent Mobility Server from activating unnecessary service. Besides, Handover Missing Problem might happen when MH moves under communication. Simultaneous Mobility Problem is a special case of Handover Missing Problem and the disruption caused by Simultaneous Mobility Problem goes beyond the typical disruption. Hence we re-send the lost message with the help of Mobility Server, and Handover Missing Problem is therefore solved.

1 Introduction 1
2 Preliminary 4
2.1 SIP Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1 SIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.2 SIP Pre-Call Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.3 SIP Mid-Call Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Mobile IP (MIP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3 UMTS/GPRS Mobility Management . . . . . . . . . . . . . . . . . . . . . . 8
2.4 CAMEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4.2 PDP Context State Model for GPRS . . . . . . . . . . . . . . . . . . 11
2.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3 3GPP VoWLAN Architecture 15
3.1 3GPP B3G Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 Key Components in 3GPP VoWLAN . . . . . . . . . . . . . . . . . . . . . . 17
3.2.1 Tunnel Establishment Flows . . . . . . . . . . . . . . . . . . . . . . . 18
3.3 IP Multimedia Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.3.2 Key Components in IMS . . . . . . . . . . . . . . . . . . . . . . . . . 22
4 Terminal Mobility in VoWLAN 25
4.1 Intra-PDG Terminal Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2 Inter-PDG Terminal Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.2.1 SIP Mobility in VoWLAN . . . . . . . . . . . . . . . . . . . . . . . . 27
4.2.2 Network-based Triggering Mechanism . . . . . . . . . . . . . . . . . . 27
5 Simultaneous Mobility Problem in VoWLAN 40
5.1 MH-Triggering Mechanism for Simultaneous Mobility Problem . . . . . . . . 40
5.2 Network-based Triggering Mechanism for Simultaneous Mobility Problem . . 41
6 Performance Analysis 46
6.1 Handover Delay Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
6.2 Handover Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
6.3 Effect of Simultaneous Mobility Problem to Handover . . . . . . . . . . . . . 50
7 Conclusion and Future Work 52
References 54

[1] Y.-B. Lin and I. Chlamtac, Wireless and Mobile Network Architectures. New York: Wiley, 2001.
[2] J.-C. Chen and T. Zhang, IP-Based Next-Generation Wireless Networks: Systems, Architectures, and Protocols. New York: Wiley, 2004.
[3] J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, and E. Schooler, “Sip: Session initiation protocol,” in IETF RFC 3261, June 2002.
[4] H. Schulzrinne and E. Wedlund, “Application layer mobility using sip,” IEEE Service Portability and Virtual Customer Environments, pp. 29–36, December 2000.
[5] Q. Wang, M. A. Abu-Rgheff, and A. Akram, “Design and evaluation of an integrated mobile ip and sip framework for advanced handoff management,” Proc. IEEE International Conference on Communications 2004, p. June, 2004.
[6] 3GPP TS22.234 v6.1.0, Requirements on 3GPP System to Wireless Local Area Network (WLAN) Interworking (Release 6), June 2004.
[7] 3GPP TS23.234 v6.1.0, 3GPP System to Wireless Local Area Network (WLAN) Interworking; System Description (Release 6), June 2004.
[8] 3GPP TR22.934 v6.2.0, Feasibility Study on 3GPP System to Wireless Local Area Network (WLAN) Interworking (Release 6), September 2003.
[9] M. Mouly and M. Pautet, The GSM System for Mobile Communications. Published by the authors, 1992.
[10] M. Rahnema, “Overview of the gsm system and protocol architecture,” IEEE Communications Magazine, vol. 31, pp. 92–100, April 1993.
[11] 3GPP TR23.060 v6.5.0, General Packet Radio Service (GPRS); Service Description; Stage 2 (Release 6), June 2004.
[12] C. Perkins, “Mobile ip,” IEEE Communications Magazine, vol. 40, pp. 66–82, 2002.
[13] 3GPP TS 23.278 v5.6.0, Customised Applications for Mobile network Enhanced Logic (CAMEL) Phase 4 - Stage 2 (Release 5), September 2004.
[14] J. Zuidweg, Next Generation Intelligent Networks. Artech House, 2002.
[15] K. Wong, A. Dutta, K. Young, and H. Schulzrinne, “Managing simultaneous mobility of ip hosts,” Military Communications Conference, 2003.
[16] “Evolute architecture specification,” EVOLUTE IST-2001-32449 D2.1, 2002.
[17] “Operational aspects of the federated service platform,” D2.3-D3.5-D4.5 version 1.0, December 2002.
[18] 3GPP TS23.228 v6.9.0, IP Multimedia Subsystem (IMS); Stage 2 (Release 6), March 2005.
[19] J. Rosenberg, J. Peterson, H. Schulzrinne, and G. Camarillo, “Best current practices for third party call control (3pcc) in the session initiation protocol (sip),” in IETF RFC 3725, April 2004.
[20] J. F. Rodriguez, “Mobility support for the vocal sip architecture,” 2004.
[21] 3GPP TS23.218 v6.3.0, IP Multimedia (IM) Session Handling; IM Call Model; Stage 2 (Release 6), March 2005.
[22] A. Niemi and Ed., “Session initiation protocol (sip) extension for event state publication,” in IETF RFC 3903, October 2004.
[23] H. Sugano, S. Fujimoto, G. Klyne, A. Bateman, W. Carr, and J. Peterson, “Presence information data format (pidf),” in IETF RFC 3863, Auguest 2004.
[24] T. T. Kwon, M. Gerla, and S. Das, “Mobility management for voip service: Mobile ip vs. sip,” IEEE Wireless Communications, vol. 9, pp. 66–75, October 2002.
[25] M. Georgiades, N. Akhtar, C. Politis, and R. Tafazolli, “Aaa context transfer for seamless and secure multimedia services over all-ip networks,” 5th European Wireless Conference (EW’04), February 2004.
[26] A. Dutta, F. Vakil, J. C. Chen, M. Tauil, S. Baba, N. Nakajima, and H. Schulzrinne, “Application layer mobility management scheme for wireless internet,” IEEE 3GWireless01, May 2001.
[27] N. Nakajima, A. Dutta, S. Das, and H. Schulzrinne, “Handoff delay analysis and measurement for sip based mobility in ipv6,” ICC 2003 - IEEE International Conference on Communications, May 2003.