Symbol-Based Physical-Layer Network Coding with MPSK Modulation

Abstract--- In this paper, the application of MPSK modulation to physical-layer network coding (PNC) with multiple antennas scheme is investigated. A linear complexity scheme with the capacity of achieving diversity is proposed assuming symbol- level synchronization only. In the proposed scheme, called symbol-based PNC, the constant amplitude of MPSK modulation symbols is exploited and the product of two end transmitted symbols, which is actually related to another modulation symbol, is considered as network code. The autocorrelation of received signal is calculated in the relay node equipped with multiple antennas, which contributes to compact the search space for the intended network code. Two detectors are designed for achieving diversity at the cost of linear complexity. We also investigate the power allocation for symbol-based PNC. The advantages of symbol- based PNC can be summarized as two points. First, it requires symbol-level time synchronization only rather than stringent carrier-phase synchronization. Second, it is linear in complexity with respect to the constellation size. Simulations show that symbol- based PNC can achieve diversity gain.