Collaborative ARQ in wireless energy-constrained networks

In this paper we propose a collaborative ARQ protocol that exploits diversity and collaboration between nodes in wireless networks. We show that when M neighboring nodes collaborate using the proposed scheme, they can achieve the BER versus SNR performance of an array of M' antennas provided that M = p/2xM' ~1.57 M', in AWGN channels or M=2M'-1 in Rayleigh channels.These results imply that collaborative ARQ can lead to huge savings in terms of power consumption. For instance, using BPSK in a Rayleigh channel and a target BER of 10-5, the required transmission power will be reduced by a factor of x180 if M=3 nodes collaborate, while the reduction factor is about x1000 for M=5. The proposed scheme does not require any modification of RF hardware, and keeps all the complexity in the firmware that processes the packets.We think that it can be of interest in wireless networks where hardware simplicity and power consumption are major design constraints.