14. Jiaqing (James) Song (jsong@sfu.ca)

Performance Evaluation and Enhancement of the Wireless Local Area Networks

Unlike the large bandwidth can be achieved by the wired networks, the bandwidth of wireless network is much more limited due to the “air”, which is the physical median used to transfer signal by WLAN, is not only error prone but also very “expensive”, so improving the performance of the WLAN is a very important topic to research.

In this project, I will explorer several important issues related to improving the performance of the WLAN from the Link Layer (Media Access Control Protocol) to the Network Layer (Transfer Control Protocol). First, I will implement several kinds of back-off algorithms used in the MAC layer and compare them with the standard back-off algorithm described in the IEEE802.11 reference. Then I will implement a link-layer protocol that is TCP-aware (such as SMART-snoop protocol). Finally, I will analysis the data gathered in the previous two steps to get the conclusion.

OPNET 8.0 is used to do the simulation.

References:

[1] N. Alborz , Lj. Trajkovic, "Implementation of VirtualClock scheduling algorithm in OPNET," OPNETWORK 2001, Washington, DC, Aug. 2001

[2] Frederico Cali, Marco Conti, Enrico Gregori, E. “Dynamic tuning of the IEEE 802.11 protocol to achieve a theoretical throughput limit”, IEEE/ACM Transactions on Networking, Volume: 8 Issue: 6 Dec. 2000

[3] Luciano Bononi , Marco Conti , Lorenzo Donatiello “Design and performance evaluation of a distributed contention control(DCC) mechanism for IEEE 802.11 wireless local area networks” Proceedings of first ACM international workshop on Wireless mobile multimedia October 1998

[4] S. Keshav and S. Morgan. "SMART Retransmission:Performance with Overload and Random Losses" In Proc. Infocom' 97, 1997.

[5] G. Anastasi , L. Lenzini "QoS provided by the IEEE 802.11 wireless LAN to advanced data applications" Wireless Networks March 2000 Volume 6 Issue 2

[6] Cali, F.; Conti, M.; Gregori, E. "IEEE 802.11 protocol: design and performance evaluation of an adaptive backoff mechanism" Selected Areas in Communications, IEEE Journal on , Volume: 18 Issue: 9 , Sept. 2000

[7] Cali, F.; Conti, M.; Gregori, E. "IEEE 802.11 wireless LAN: capacity analysis and protocol enhancement" INFOCOM '98. Seventeenth Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings. IEEE, Volume: 1 , 1998

[8] Song Ci , Hamid Sharif , Guevara Noubir "Improving performance of MAC layer by using congestion control/avoidance methods in wireless network" Proceedings of the 16th ACM SAC2001 symposium on Applied computing March 2001

[9] LAN MAN Standards Committee of the IEEE Computer Society "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications" ANSI/IEEE Std 802.11, 1999 Edition

[10] OPNET technologies, Inc., "Wireless LAN Model Description" http://www.opnet.com/products/library/WLAN_Model_Guide1.pdf