A new efficient selective repeat protocol for point-to-multipoint communication

Selective repeat automatic-repeat-request (ARQ) protocols for use in a point-to-multipoint communication over broadcast links are considered. In this context, a new approach called XOR strategy, based on the selective repeat strategy for capacity enhancement of a communication channel, is suggested. The idea of the XOR selective repeat strategy is to physically combine several blocks negatively acknowledged (NACKed) by different receivers by XORing (i.e., modulo 2 addition) to minimize the number of retransmissions and to increase throughput. Five different implementations of the XOR strategy and the pure selective repeat strategy are compared in terms of throughput. The XOR protocols differ in the applied algorithms for the XORing of NACKed data blocks. The analytical and simulative results show that, in terms of throughput, all five XOR strategies yield remarkably better results than the pure selective repeat