Algorithm for Optimizing Packet Size in Mobile Ad Hoc Networks

This thesis proposes an algorithm to optimize packet size in mobile ad hoc networks (MANET). In this thesis, the packet size is adapted to maximize the communication performance through the automatic repeat request (ARQ) protocol. The optimal packet size is chosen by an algorithm based on the estimation of the channel from the number of retransmission requests and the link statistics obtained from the mobility pattern. By adapting the non-uniform distribution of the bit error rate (BER) obtained from the mobility pattern analysis, it is possible to estimate channel conditions more accurately from the number of retransmission requests and to improve the system performance. It was found that the distribution of the link distance among mobile nodes following the Gauss-Markov mobility pattern in a circularly shaped area well fits the Beta distribution function. From the simulation results it is observed that when the interference increases, or the path loss exponent increases, or when the size of history decreases, the throughput and efficiency performance will decrease. Based on an analysis in various wireless environments, the algorithm proposed in this thesis shows almost an optimal throughput efficiency performance, and it gives better performance than the algorithm in [6], which uses an uniform distribution function for the estimation of the channel condition. By adapting the Beta distribution of the BER obtained from the mobility pattern, it is possible to estimate the channel conditions more accurately from the number of retransmission requests and to improve the throughput and utilization performance of MANET communication systems.School of Electrical & Computer Engineerin