A simple physical-layer network coding with fractional delay

Decode-and-forward physical-layer network coding (PLNC) is one of the promising high-performance techniques for wireless relay networks, but little has been reported on the case of asynchronous scenarios using practical pulse shaping waveform. This paper presents a simple encoding and decoding scheme for asynchronous Two-Way relay network (TWRN). At user terminals, symbol are separately modulated on I/Q channels. At the relay, different from the traditional decoding procedure, where the relay estimates the XOR result of the two source data streams, our scheme uses two outputs of the matched filter, estimates each source data separately using vector resolution, and then perform the XOR operation to improve the performance. BER performance of the proposed scheme under perfect and imperfect pre-coding is analyzed. Simulation validates our analysis and shows the effectiveness of the proposed scheme under a synchronization, especially under fractional delay.