Four-node Relay Network with Bi-directional Traffic Employing Wireless   Network Coding with Pre-cancellation
  Network coding has the potential to improve the overall throughput of a network by combining different streams of data and forwarding them. In wireless networks, the wireless channel provide an excellent medium for physical layer network coding as signals from different transmitters are combined automatically by the wireless channel. In such scenarios, it would be interesting to investigate protocols and algorithms which can optimally relay information. In this paper, we look at a four-node two-way or bidirectional relay network, and propose a relay protocol which can relay information efficiently in this network. 
Su Kiang Kuek, Chau Yuen, Woon Hau Chin