A simple non-coherent Physical-layer Network Coding for transmissions over two-way relay channels

Physical-layer Network Coding (PNC) can effectively improve the overall throughput of a multi-hop cooperative network communicating over two-way relay channels. In this contribution, we present a novel non-coherent/differential PNC scheme, which inherits the advantages provided by conventional PNC. We show that, although the assisting relay node has no access to the Channel State Information (CSI), our proposed non-coherent PNC detector with a low-complexity dual-branch structure is still capable of acquiring the network-coded symbols directly from a linearly superimposed signal. Compared with conventional two-way relay systems employing an inefficient four time-slot scheduling protocol, non-coherent PNC aided bidirectional cooperation scheme is able to double the throughput by elimination of two transmission periods. Therefore, significant improvements in the spectral efficiency and network capacity can be attained by incorporating this novel non-coherent PNC technique in the two-way relaying scenario.