An Adaptive Duplex Switching Scheme That Exploits Interference Statistics for Hybrid-Duplex Cellular Networks

The full duplex (FD) technique allows transmission and reception in the same frequency band and at the same time. It can potentially improve the spectral efficiency. However, in a cellular network, FD communication results in increased interference which may diminish the gain. It has been shown that hybrid designs with proper selection between the FD and the half duplex (HD) modes can reach a performance better than that of the pure FD and pure HD systems. The optimal mode selection requires accurate channel information within a cell and between cells which incur a significant amount of signaling overhead and the computation is highly complex. In this paper, we propose a duplex switching method based on only the instantaneous channel information within a cell and the statistics of the other-cell interference to avoid extensive information exchange and complex computation. The other-cell interference depends on the portions of the links in the other cells adopting the FD or HD mode, which again depend on the other-cell interference these links see. Due to this recursion or interaction between cells, the interference statistics are difficult to derive. Using stochastic geometry, we propose an approximation approach to obtain the probability of other cells adopting the FD mode, and use this probability to approximate the other-cell interference which is then exploited for duplex mode switching in a cell. Simulation results show that the proposed design outperforms the pure FD, pure HD, and an existing duplex switching system. Surprisingly, it also outperforms a system with mode selection based on the actual instantaneous other-cell interference.