Enhancing System Spectral Efficiency in Cellular Networks via Full-Duplex D2D Communications

In this paper, we investigate the benefits of integrating underlaid device-to-device (D2D) communications in cellular networks in terms of spectral efficiency gain with D2D users operating in half-duplex (HD) and full-duplex (FD) under the presence of residual self-interference. Based on stochastic-geometry, we develop analytical expressions for the sum-rates of D2D links in order to characterize their behaviors under the effects of various system parameters. Numerical results are provided to illustrate such behaviors. It is shown that, with a sufficient self-interference cancellation level, FD D2D can provide substantial spectral efficiency improvement over the HD counterpart. Underlaid D2D communications in cellular network also offers a significant spectral efficiency gain over the pure cellular networks, especially in dense D2D deployment.