In the dynamic multicast environment, static multicast retransmission modes may lead to congestion and loss of packets due to propagation errors of the wireless network. This paper logically divides the dynamic multicast network into fixed and mobile parts, and focuses on the dynamic wireless environment, where mobile member may enter in non-covered areas. The group is divided into many subgroups of mobile members. Each subgroup has one Designated Receiver (DR), which is responsible of multicast. Simulation studies have been conducted to determine the benefits of integrating an improved Forward Error Control (FEC) codes to a reliable multicast protocol P_Mul in the dynamic environment. Members can leave and join the subgroup based on some distributions. DR can support two modes of FEC, proactive and reactive. The simulation tool using OPNET shows that reactive FEC is better with high rate of leave and low rate of join. However, for proactive FEC, it is the opposite. Also, simulation results show that the number of designated receivers is parabolic with respect to the number of retransmissions. This paper investigates the benefits of an improved FEC mechanism for the reliable dynamic wireless networks.

[1]Araar A. and Khali H., “A Simulation Study for a Dynamic Multicast Protocol Using FEC,” in Proceedings of the IEEE International Conference on Electronics and Circuits Systems (ICECS) , Sharjah, UAE, pp. 523-526, December 2003.

[2] Bilodeau C. and Dumoulin S., “A Simulation of P_Mul,” Technical Reprot, Communication Research Center DRE, Ottawa, June 2000.

[3] Cordeiro C. M., Gossain H., and Agrawal P., “Multicast over Wireless Mobile Ad-Hoc Networks: Present and Future Directions,” IEEE Network , Special Issue on Multicasting: An Enabling Technology , January-February 2003.

[4] Gossain H., Cordeiro C. M., and Agrawal P., “Multicast: Wired to Wireless,” IEEE Communications Magazine , June 2002.

[5] Handley M., Whetten B., Kermode R., Floyd S., Vicisano L., and Luby M., “The Reliable Multicast Design Space for Bulk Data Transfer,” IETF Informational RFC'2887, August 2000.

[6] Lehman L., Garland S., and Tennenhouse D., “Active Reliable Multicast,” in Proceedings of the IEEE INFOCOM , pp. 581-589, 1998.

[7] Lin S. and Costello D. J., Error Control Coding: Fundamentals and Applications , Prentice Hall, 1983.

[8] Matsumoto M. and Nishimura T., “Mersenne Twister MT 19937: A Pseudorandom Number Generator,” http://www.math.keio.ac.jp/matumo to/emt.html.

[9] McAuley A., “Reliable Broadband Communication Using a Burst Erasure Correcting Code,” in Proceedings of the ACM Sigcomm , Philadelphia, 1990.

[10] Obraczka K., “Multicast Transport Protocols: Survey and Taxonomy,” IEEE Communications Magazine , vol. 36, 1997.

[11] OPENT, “OPNET Simulation Tool,” http://www. mil3.com.

[12] “P_Mul: A Protocol for the Reliable Multicast Messaging in Bandwidth Constrained and Delayed Acknowledgement (EMCON) Environment,” Allied Communications Publications, 2001

[13] “Reliable Multicast Transport (RMT) working group,” Http://www.ietf.org/html.charters/rmt- charter.html.

[14] Rizzo L., “Effective Erasure Codes for Reliable Computer Communication Protocols,” ACM Computer Communication Review , vol. 27, no. 2, pp. 24-36, 1997.

[15] Rizzo L. and Vicizano L., “RMDP: An FEC- Based Reliable Multicast Protocol for Wireless Environments,” Mobile Computing and Communication Review , vol. 2, 1998.

[16] Sadok D., Cordeiro C., and Kelner J., “Performance Analysis of a Multicast Protocol for Wireless Environments,” Journal of the Society for Computer Simulation International (JSCS) , Special Issue on Mobile and Wireless Communication and Information Processing , vol. 75, no. 1, July 2000.

[17] Tovirac J. and Zhang W., “A Simulation Study of P_Mul Multicasting Protocol Enhanced by Ideal FEC Code,” in Proceedings of the IASTED International Conference on Wireless and Optical Communications (WOC'2002) , pp. 493- 498, Banff, Canada , July 2002.

[18] Whetten B., and Taskale G., “An overview of Reliable Multicast Transport Protocol II,” IEEE Network , vol. 14, pp. 37-47, 2000.

[19] Xinjie C., “Network Simulation with OPNET,” in Proceedings of the Winter Simulation Conference , 1999. Abdelaziz Araar is an associate professor at the Faculty of Computer Science and Computer Engineering at Ajman University of Science and Technology Network, UAE. He received his BSc in computer science from University of Annaba in 1983, his MSc in computer science in 1986, and then his PhD in 1991 form Case Western Reserve University, Cleveland, Ohio, USA. His area of interest is mainly advanced simulation models for networking, wireless communication, intelligent systems, and other applications. Hakim Khali is an assistant professor at the Faculty of Computer Science and Computer Engineering at Ajman University of Science and Technology Network. He got his BSc in computer engineering from INI, Algeria, in 1989, and his MSc and PhD in 1993 and 2000, respectively, from Ecole Poytechnique of Montreal, Canada. His research interests are hardware-software codesign, VLSI architectures, and FPGA-based designs for neural networks and cryptography. Before joining Ajman University, he worked as a system designer for Mirotech Microsystems on reconfigurable computing systems. He is an IEEE member. 140 The International Arab Journal of Information Technology, Vol. 2, No. 2, April 2005 Riyadh Mehdi is currently an associate professor of computer science at Ajman University of Science and Technology Network since September 2000. He obtained his MSc degree in software engineering in 1988, and his PhD degree in computer science in 1990, both from Liverpool University, UK. His research interests are mainly in fuzzy logic, expert systems, neural networks, and their applications in the area of expert systems, image processing, and intelligent agents.