Two-way non-coherent Physical-Layer Network Coded differential distributed space-time block coding

In this contribution, we propose a novel differential distributed space-time block coding (DDSTBC) scheme for multirelay assisted two-way cooperative networks. A low-complexity non-coherent Physical-layer Network Coding (PNC) algorithm is first investigated, which allows direct extraction of network coded symbols from the received superimposed signal at the relay node without knowledge of Channel State Information (CSI). We show that, although the DDSTBC codewords are constructed by a group of single antenna aided cooperating nodes, the proposed scheme is still capable of attaining full transmit diversity order. The negative effect of error propagation suffered at the relay-to-destination link is addressed using a simple CRC-based selective relaying protocol. In addition, the employment of differential PNC at the intermediate relay node significantly improves the overall network throughput by exchanging information between two users simultaneously.