Physical layer network coding with channel and delay estimation

Decode-and-forward physical layer network coding (PLNC) is one of the promising high-performance techniques for wireless relay networks. This study presents a channel and delay estimation algorithm along with a detection scheme for time-domain two-way relay network in Rayleigh block fading channels. Preambles are attached for frame-based synchronisation and channel estimation. Moreover, to achieve low-complexity estimation, the preambles are designed in Alamouti code structure. The Cramer-Rao bound (CRB) of the channel estimation is given, and simulations show that the mean-square error of channel estimation of the proposed scheme could reach the CRB. Compared with the traditional approach, the newly proposed combined scheme can achieve almost the same performance, but with significant improvement in computational complexity. At last, bit-error-rate performances analysis is given. Simulation validates the authors´ analysis, and shows the upper bound and lower bound are tight.