Opportunistic cooperative transmission scheme based on network coding in wireless sensor networks

In this paper, we propose an opportunistic cooperative transmission (OCT) scheme combined with bi-directional relaying and physical layer network coding (PNC) in wireless sensor networks (WSNs).This scheme can be switched between PNC based distributed space-time block coding scheme and cooperative network-assisted diversity multiple access scheme to obtain the minimized frame-error-ratio (FER) performance. We analyze the FER performance difference when the two schemes are adopted separately to find the location of the relay where the system should change its cooperative scheme to obtain the smaller FER. Numerical and simulation results demonstrate that lower error rate can be obtained wherever the relay locates in the proposed scheme.