Uncoordinated cooperative truncated ARQ schemes in wireless systems

In this paper, we propose two uncoordinated cooperative truncated ARQ schemes based on node position or local SNR information. If the original transmission between a source and a destination fails, the source and all the potential relays that have correctly received the data packet will contend for the channel to retransmit the packet without coordination. The competition for the channel access is governed by the retransmission probability which is computed in a distributed fashion using the stochastic geometry theory. Theoretical system success probabilities of both schemes are derived. Compared with the scheme in which only the source retransmits, the uncoordinated schemes are shown to achieve better performance, particularly when the distance between the source and the destination is large.