為了提供寬頻的個人行動通訊無線上網，行動通訊由迴路切換（circuit switching）演進到封包切換（packet switching），明顯的例子是全球式行動通訊系統（GSM）到一般封包式無線電服務（GPRS）的演進，而廣域發展加強型傳輸(EDGE)的機制更是因為為了提供更大的無線網路頻寬在被利用，因此第三代無線網路應聲的被提出。
由於無線網路上的干擾問題一直是影響無線傳輸品質的主要因素，而干擾的發生，會因為手機的位置在遭受不同干擾的程度，此外，當手機對某一個頻道產生干擾時，其他的手機對於這一個頻道可能因為沒有干擾而得以利用這個頻道來增加頻道的使用率，因此，我們針對這個干擾的問題來提出我們的解決方案，為了讓無線網路的使用更有效率，我們勢必要將傳送的資料給予分類，以應當手機遭受干擾時，能有不同的處理機制，由歐洲電信標準協會（ETSI）所提出的四種資料類別：(1) 通話類別(conversational class) (2) 資料流類別(streaming class) (3) 互動型類別(interactive class) (4) 背景執行類別(background class)，做為我們對資料方類的依據，我們認為在傳輸的重要性方面，通話類別和資料流類別因為需要即時性的傳輸，因為具有比較高的權力（priority）去使用頻道（channel），而互動型類別和背景執行類別可以利用有干擾的頻道去傳送資料。

在這一篇論文中，我們提出了一些讓系統頻道更有效率的被利用，由實驗的模擬同樣的得到了數據上的驗證。

The state-of-the-art cellular networks such as General Packet Radio Service system (GPRS) with Enhanced Data rates for Global Evolution (EDGE) air interfaces can support a wide variety of applications, e.g., web browsing and video conferencing. The desired quality of communication channels, however, for such wireless networks depends on the interferences contributed by the location errors and the signal strength elapsed. To accommodate different Quality-of-Service (QoS) classes for such widely received applications, an efficient scheduling for air interfaces must be essentially supported. In this study, we propose a dynamical scheduling algorithm by together taking the interferences and varying QoS requirements into considerations for GPRS with EDGE air interfaces. Conceptually, the proposed scheme assigns priority orderly to the conversational, streaming, interactive and background traffic classes defined by ETSI. Each channel is equipped with an A-buffer to gather the acknowledge messages of the successfully transmitted packets to measure the utilization of the associated channel. A global monitor device tracks the state of each mobile station. Based on the measured channel utilizations and the states of mobile stations, the proposed scheduling dynamically assigns channels to the ongoing traffics. From the event-driven simulations, the scheme can significantly outperform the scheme without any support of dynamically channel assignments especially for the interactive and background traffic classes.

[1] D. Calin, S. Malik and D. Zeghlache,“ Traffic Scheduling and Fairness for GPRS Air Interface,” in Proc. of Vehicular Technology Conference, vol. 2, pp. 834 –838, Fall 1999.
[2] C. Johansson, L. D. Verdier and F. Khan,“ Performance of Different Scheduling Strategies in a Packet Radio System,” in Proc. of International Conference on Universal Personal Communications, vol. 1, pp. 267 –271, 1998.
[3] P. Bhagwat, P. Bhattacharya, A. Krishna and S.K. Tripathi,“ Enhancing throughput over wireless LANs using channel state dependent packet scheduling,” in Proc. of IEEE INFOCOM 1996, vol. 3, pp. 1130-1140, 1996.
[4] X. Qiu, K. Chawla, L. F. Chang, J. Chuang, N. Sollenberger and J. Whitehead,” RLC/MAC Design Alternatives for Supporting Services over EGPRS,” IEEE Personal Communications, vol. 7 2, pp. 20-33, April 2000.
[5] G. Priggouris, S. Hadjiefthymiades and L. Merakos,” Supporting IP QoS in the General Packet Radio Service,” IEEE Network, vol. 14 5, pp. 8-17, September/October 2000.
[6] D. A. Eckhardt and P. Steenkiste,” Effort – limited Fair (ELF) Scheduling for Wireless Networks,”in Proc. of IEEE INFOCOM 2000, vol. 3, pp.1097-1106, 2000.
[7] T. Uehara, T. Seto and Y. Akaiwa,” A Dynamic Channel Assignment Method for Voice Packet Transmission Cellular System,” in Proc. of Vehicular Technology Conference, vol. 3, pp. 2500-2504, 1999.
[8] Special Issue on “The Evolution of TDMA to 3G,” IEEE Personal Communications, Vol. 6, no. 3, June 1999.
[9] ETSI GSM 03.60 v.7.1.0, “Digital Cellular Telecommunications System (Phase 2+); General Packet Radio Service (GPRS); Service Description; Stage2,” 1998.
[10] A. Furuskar, “EDGE: Enhanced Data Rates for GSM and TDMA/136 Evolution,” IEEE Personal Communications, vol. 6 3, pp. 56-66, June 1999.
[11] X. Wu, K. L. Yeung and J. Hu, “Efficient Channel Borrowing Strategy for Real-Time Services in Multimedia Wireless Networks,” IEEE Transactions on Vehicular Technology, vol. 49, no. 4, pp. 1273 –1284, July 2000.
[12] D. J. Goodman and S. X. Wei,“ Efficiency of Packet Reservation Multiple Access,” IEEE Transactions on Vehicular Technology, vol. 40, no. 1, pp170-176, February 1991.
[13] J. Ho, Y. Zhu and S. Madhavapeddy,“ Throughput and Buffer Analysis for GSM General Packet Radio Service (GPRS),” in Proc. of Wireless Communications and Networking Conference, vol.3, pp. 1427 –1431, 1999.
[14] Q. Pang, A. Bigloo, V. C. M. Leung and C. Scholefield, “Service Scheduling for General Packet Radio Service Classes,” in Proc. of Wireless Communications and Networking Conference, vol. 3, pp. 1229 –1233, 1999.
[15] J. S. Swarts and H. C. Ferreira,“ On The Evaluation and Application of Markov Channel Models in Wireless Communications,” in Proc. of Vehicular Technology Conference, vol. 1, pp.117 –121, Fall 1999.
[16] J. E. Wieselthier and A. Ephremides, “Fixed- and movable-boundary channel-access schemes for integrated voice/data wireless networks,” IEEE Transactions on Communications, vol. 43, pp.64-74, January 1995.
[17] M. Elaoud and P. Ramanathan,“ Adaptive allocation of CDMA resources for Network-level QoS Assurances,” in Proc. of International Conference on Mobile Computing and Networking, pp.191-199, 2000.
[18] L. Chen, S. Yoshida and H. Murata, “A Dynamic Channel Assignment Algorithm for voice and data integrated TDMA mobile radio,” in Proc. of Personal, Indoor and Mobile Radio Communications, vol. 1, pp.213-217, 1996.
[19] M. Inoue, G. Wu and Y. Hase,” Resource Scheduling with Channel State Information for Wireless Message,” in Proc. of International Conference on Universal Personal Communications, vol. 1, pp. 249-253, 1998.
[20] J. E. Wieselthier and A.Ephremides,“ Fixed and movable-boundary channel-access schemes for integrated voice/data wireless networks,” IEEE Transactions on Communications, vol. 43, pp.64-74, January 1995.
[21] Z. Jiang, L. F. Chang and N. K. Shankaranarayanan, “Providing Multiple Service Classes for Bursty Data Traffic in Cellular Networks,”in Proc. of IEEE INFOCOM 2000, vol. 3, pp.1087-1096, 2000.
[22] K. Oosaki and Y. Akaiwa,“ A Dynamic Radio Channel Assignment Considering Data Packet Length and Channel Quality,” in Proc. of Vehicular Technology Conference, vol. 2, pp.1333-1337, Spring 2000.
[23] J. E. Wieselthier and A. E.phremides, “Fixed- and Movable-Boundary Channel-Access Schemes for Integrated Voice/Data Wireless Networks,” IEEE Transactions on Communications, vol. 43, pp. 64 -74, January 1995.
[24] http://ita.ee.lbl.gov/html/contrib/EPA-HTTP.html