Constellation Mapping for Physical-Layer Network Coding With M-QAM Modulation
The De-Noise-and-Forward (DNF) method of Physical-layer Network Coding (PNC) is a promising approach for wireless relaying networks. In this paper, the authors consider DNF-based PNC with M-ary Quadrature Amplitude Modulation (M-QAM) and propose a mapping scheme that maps the superposed M-QAM signal to coded symbols. The mapping scheme supports both square and non-square M-QAM modulations, with various original constellation mappings (e.g. binary-coded or Gray-coded). Subsequently, they evaluate the symbol error rate and Bit Error Rate (BER) of M-QAM modulated PNC that uses the proposed mapping scheme. Afterwards, as an application, a rate adaptation scheme for the DNF method of PNC is proposed. Simulation results show that the rate-adaptive PNC is advantageous in various scenarios.