Adaptive physical layer network coding

In this paper, we propose a new adaptive physical layer network coding (APLNC) protocol for two-way relay channels where bidirectional information flow between two terminals is simultaneously achieved with the help of one or two relays when N relays are available. The adaptive protocol consists of a selection between all possible realizations of the two-way transmission based on a criterion which maximizes the instantaneous achievable sum rate. Outage probability analysis as well as bit error rate performance results obtained by computer simulations show that significant performance improvement is provided by the proposed adaptive protocol compared to the classical straightforward network coding (SNC) and PLNC. Moreover APLNC offers a solution to the poor error performance of the classical cooperative communication protocols at low signal-to-noise ratio (SNR) region.