Analysis of a Distributed Queuing Medium Access Control Protocol for Cooperative ARQ

In this paper we analyze the performance of a distributed queuing medium access control (MAC) protocol designed to execute cooperative ARQ (C-ARQ) schemes at the MAC layer. Due to the broadcast nature of the wireless channel, a user that receives a data packet with unrecoverable errors can request retransmission from any of the other users in the transmission range of the transmitter that overheard the original transmission. These users can act as spontaneous relays and provide the communication with cooperative diversity gains. Upon retransmission request, the relays have to contend for the access to the channel. The DQCOOP protocol has been proposed in the literature as a high-performance MAC protocol for this kind of scenario. In this paper we theoretically evaluate its performance. The analytical results are supported by computer-based simulation that show the accuracy of the analysis.