Channel-Coded Physical-Layer Network Coding With OFDM Modulation

摘要: This paper addresses the carrier frequency offset (CFO) problem in OFDM modulated physical-layer network coding (PNC) operated a two-way relay channel (TWRC). CFO, caused by node-motion induced Doppler shifts and/or asynchronous oscillators, induces inter-carrier interference (ICI) between subcarriers and hence, degrades PNC performance. To mitigate CFO/ICI effect PNC, this considers channel-coded focuses on receiver design at relay. CFO compensation, signal detection, decoding are three basic processing blocks node. For latter two, we consider both joint separate design. design, construct factor graph to integrate with ICI, then, propose scheme based belief propagation. two low-complexity schemes differing proposed. Our simulation results, using repeat-accumulate codes, reveal that (1) compensation approach amounts positioning relay’s oscillator middle of received frequencies from end nodes is bit error rate (BER)-optimal for all schemes; (2) superior low SNR high levels; (3) more importantly, low-to-medium levels, BER comparable traditional point-to-point communications without thus manifesting itself as promising technique TWRC practical constraints.