An Optimum Segmentation Algorithm for Air Force Packet-DAMA

A large community of bursty users can share a small number of satellite channels by employing a highly disciplined demand assignment multiple access (DAMA) protocol. One candidate DAMA design under consideration by the Air Force uses packet-switching techniques originally developed for large computer networks. This "packet-DAMA" approach divides the satellite time into periodic structures called frames. Within each frame are a control subframe and an information subframe. In this paper, an exact expression for the optimum packet size is derived. This optimum packet size depends only on the amount of packet overhead and the net bit error rate (BER) of the channel. Since BER can be estimated by decoders in many instances, this suggests the possibility of dynamic packet size determination. Also addressed in this paper is the penalty for using suboptimum packets. This issue is unique to packet-DAMA, where the frame structure may prevent the use of optimum packets.