Constructive Interference based Co-operative NOMA Full Duplex Downlink System

Non-orthogonal multiple access (NOMA) is the promising candidate to improve the spectral efficiency and system throughput in fifth-generation (5G) mobile communication networks. In this paper, we consider a co-operative non-orthogonal multiple access (CR-NOMA) system with dual users. The user closer to the base station (BS) acts as a full-duplex (FD) relay to assist the information transmission to the cell edge user. Instead of mitigating self-interference in FD systems, we propose to use the knowledge of Data information (DI) and the channel state information (CSI) at the BS to exploit the self-interference constructively rather than to suppress it. For Constructive interference based (CI) FD NOMA system, we derive an exact analytical expression for the outage probability of both users and system throughput. Numerical results are carried out to investigate the proposed CI FD-NOMA system and compared with the state of art HD and FD NOMA scenarios. It is observed that the proposed system performs better than the conventional HD/FD NOMA system.