GSIC for Uplink NOMA With Multiple Intelligent Reflecting Surfaces

Abstract

Intelligent reflecting surface (IRS) is treated as a cutting-edge technology to boost spectrum and energy efficiency for future wireless communications. In this letter, multiple IRSs are deployed to obtain better performance of cell-edge users and group-level successive interference cancellation (GSIC) is conceived to distinguish the users' signals of different groups. In order to get the minimum overall transmission power for IRS-assisted uplink multi-antenna non-orthogonal multiple access (NOMA) systems, all user's transmission power and the IRSs' phase shifts are jointly devised to achieve this goal. Particularly, a sequential rotation method is applied to optimize phase shifts effectively. It is clearly illustrated from simulation results that our proposed scheme can dramatically decrease total transmit power in comparison with a variety of benchmarking methods.