On the Study of Network Coding With Diversity

Recently proposed Physical-layer Network Coding (PNC) has demonstrated the promise to significantly improve the throughput of wireless networks whose links can be modeled as Additive White Gaussian Noise (AWGN) channels. However, the extension to multipath channels is problematic, since the technique would then require both amplitude and phase compensation at each transmitter. Phase compensation requires accurate distributed phase tracking, whereas the required amplitude compensation is even more troubling, as it leads to an inefficient system that yields no diversity even in the presence of perfect channel estimates. Here, a system that avoids these limitations is obtained by reaching up one level higher in the network hierarchy and performing distributed relay selection with cognizance of the PNC technique that the authors will employ at the physical layer.