Design robust receiver against channel estimation error in MIMO-NOMA system

One of the non-orthogonal access techniques is non-orthogonal multiple access (NOMA) that is known as an access technique with high spectral efficiency. The combination of NOMA technique and MIMO system which is called MIMO-NOMA system has been offered in order to achieve higher capacity and spectral gain for 5G mobile communication. The performance of communication systems especially MIMO-NOMA system, significantly depends on channel estimation accuracy as the system efficiency decrease dramatically in the presence of channel estimation error. In this paper, the channel estimation error effect in downlink MIMO-NOMA system is investigated and a new detector which aims to improve the performance of system is proposed despite the channel estimation error. The proposed detector decreases both the effects of channel estimation error and the interference of user in three steps. Simulation results indicate that the proposed detector decreases the error probability and improves the system performance compared to that of the MMSE detector for far user and MMSE-SIC detector for near user considerably.