無線通訊網路與手機網路這近年來熱門研究，在目前市場上屬較成熟的無線通訊網路技術當推2.5G的GPRS與無線區域網路，為了要讓此兩不同系統網路能相互運作，提出一個能在兩系統中漫遊整合方法，儘可能減低對現有系統的影響，且針對此方法做效能上的研究與探討。
利用閘道器的方法來解決在兩系統中行動管理上的問題，此閘道器置於GPRS與無線網路的連接點上，且遵循IETF制定的Mobile IP來提供行動管理的功能。本論文是針對此閘道器做效能上的分析，分別對訊號和資料庫成本(Signaling and Database Cost)、漫遊延遲時間(Handoff Latency)、閘道器上緩衝區大小(Buffer Size)各提出一套數學模組來代表這三方面效能分析。在訊號和資料庫成本(Signaling and Database Cost)方面，提出一個簡單且快速數學模組來代表每個使用者在GPRS和WLAN系統中所花費的訊號與資料庫成本。由於本方法是整合兩套系統，漫遊延遲時間對業者或使用者是相當關心的，利用排對理論，提出一個可模組送出Mobile IP註冊訊息到收到註冊成功訊息的過程，此模組是使用MMPP(Markov-Modulated Poisson Process)當作使用者資料量(Traffic)，每個使用者都以MMPP方式去傳送資料，每個系統結點(system node)都模組成MMPP/M/1，利用此方法能算出漫遊延遲時間在此兩系統中。最後一部分是分析如何設定閘道器上緩衝區大小，多個使用者的資料量和緩衝區大小表現在所提出的模組中，依據阻礙機率(Blocking Probability)來判斷緩衝區的狀態，且針對阻礙機率來設定出正確的緩衝區大小。此閘道器的方法已經在台灣大哥大和工研院實作出來，本論文提出的模組可供他們對閘道器效能更深入的了解，透過完整模擬的結果，可驗證本論文提出的分析模組。

This paper presents the design and analysis of GPRS-WLAN Mobility Gateway (GWMG) for the integration of GPRS and wireless LANs (WLANs). The proposed architecture leverages
Mobile IP as the mobility management protocol over WLANs. The interworking between GPRS and WLANs is achieved by the GWMG which resides on the border of GPRS and WLAN systems. The design goal is to minimize the modications in GPRS and WLANs as that both systems are widely available in the market already. By deploying the GWMG, users can seamlessly roam among two systems. Both mathematical analysis and simulation are developed to analyze the performance. The analysis models include the cost, handoff latency, and buffer size. The proposed GWMG has also been implemented in a commercial GPRS system. The results show that the GWMG could achieve the design goal to effectively integrate GPRS and WLANs.

[1] 3GPP TR 22.934. Feasibility study on 3GPP system to wireless local area network
(WLAN) interworking, Sept. 2003.

[2] 3GPP TR 23.234. 3GPP system to wireless local area network (WLAN) interworking;
system description, Jan. 2004.

[3] 3GPP TS 23.060. General packet radio service (GPRS); service description; stage 2,
2002.

[4] 3GPP TS 29.060. General packet radio service (GPRS); GPRS tunneling protocol
(GTP) across the G_n and G_p interface, 2002.

[5] 3GPP TS 29.061. Packet domain; interworking between the public land mobile network
(PLMN) supporting packet based services and packet data network (PDN), 2002.

[6] ALA-LAURILA, J., MIKKONEN, J., AND RINNEMAA, J. Wireless LAN access network
architecture for mobile operators. IEEE Communications Magazine (Nov. 2001),
82-89.

[7] AUST, S., PROETEL, D., KONSGEN, A., PAMPU, C., AND GORG, C. Design issues
of mobile IP handoffs between general packet radio service (GPRS) networks and wireless
LAN (WLAN) systems. In Proc. of the 5th International Symposium on Wireless
Personal Multimedia Communications (Hawaii, USA, Oct. 2002), pp. 868-–872.

[8] ETSI TR 101 957. Requirements and architectures for interworking between HIPERLAN/
2 and 3rd generation cellular systems, Aug. 2001.

[9] FISCHER, W., AND MEIER-HELLSTERN, K. The Markov-modulated Poisson process
(MMPP) cookbook. Performance Evaluation 18 (1992), 149-–171.

[10] HEFFES, H., AND LUCANTONI, D. A Markov modulated characterization of packetized
voice and data trafc and related statistical multiplexer performance. IEEE J.
Selected Areas Comm. 4(6), 1986.

[11] JIANG, M.-C., CHEN, J.-C., AND LIU, Y.-W. WLAN-centric authentication in integrated
GPRS-WLAN networks. In Proc. of IEEE Vehicular Technology Conference
(Orlando, FL, USA, Oct. 2003).

[12] LIN, H.-W., CHEN, J.-C., JIANG, M.-C., AND HUANG, C.-Y. Integration of GPRS
and wireless LANs with multimedia applications. Lecture Notes in Computer Science:
Advances in Multimedia Information Processing - PCM 2002, Springer, 2532 (Dec.
2002), 704-–711.

[13] MORAND, L., AND TESSIER, S. Global mobility approach with Mobile IP in all
IP networks. In Proc. of IEEE International Conference on Communications (ICC)
(2002), pp. 2075–2079.

[14] NAOR, P., AND YECHIALI, U. Queueing problems with heterogenous arrivals and
service. Oper. Res. 19, 1971.

[15] NEUTS, M. F. A queue subject to extroneous phase changes. Adv. Appl. Probab. 3,
1971.

[16] NEUTS, M. F. Matrix-Geometric Solutions in Stochastic Modeling: An Algorithmic
Approach. Baltimore, MD:Johns Hopkins University Press, 1981.

[17] SALKINTZIS, A. K., FORS, C., AND PAZHYANNUR, R. WLAN-GPRS integration for
next-generation mobile data networks. IEEE Wireless Communications 9 (Oct. 2002),
112-–124.

[18] TRIVEDI, K. S. Probability and Statistics with Reliability, Queuing and Computer
Science Applications. Wiley, 2002.

[19] YLIANTTILA, M., PANDE, M., M¨AKEL ¨A, J., AND M¨AH ¨ONENI, P. Optimization
scheme for mobile users performing vertical handoffs between IEEE 802.11 and
GPRS/EDGE networks. In Proc. of IEEE GLOBECOM (2001), vol. 6, pp. 3439-3443.