A new physical layer network coding de-noising mapping based on M-QAM

To overcome the problem of constellation points ambiguity in physical layer network coding (PLNC), this paper proposes a new QAM-based PLNC de-noising mapping scheme. In this scheme, the relay node rearranges the M-QAM constellation mapping, and merges the points of constellation according to a certain rule. Comparing with traditional scheme, this design reduces the number of constellation points nearly a half, which increases the Euclidean distance between adjacent points in the constellation, thus improves the BER performance. In addition, the relay node only needs demodulation - remapping - modulation, which significantly reduces the processing complexity. Simulation results show the effectiveness of our scheme.