On rate region analysis of full-duplex cellular system with inter-user interference cancellation

Full-duplex (FD) technology has been regarded as a promising solution to improve the spectral efficiency of the 5th generation (5G) wireless communication system. In this paper, we focus on a small-area radio system, where a FD base-station serves two half-duplex users simultaneously with one in the uplink and the other one in downlink direction. However, the self-interference (SI) and the inter-user interference (IUI) may largely degrade the system performance. Therefore we propose a simple but effective inter-user interference cancellation (IIC) strategy to cope with the IUI. This method is based on the fact that the downlink user observes a multiple access channel (MAC) of two user, the BS and the uplink user, respectively. Hence, the downlink user has an opportunity to remove the IUI according to the transmission rates and its received powers. Therefore, we call this method as multi-access channel IIC (MIIC). Then, we analyze the achievable rate region of the FD system with and without MIIC when taking the SI into consideration. To obtain the rate region, analytic power allocation strategies are derived. Simulation results show that, by applying the proposed power allocation strategies, the performance of FD system with MIIC is as good as the system without IUI under the 3GPP assumptions.