Power Minimization for Two-Cell IRS-Aided NOMA Systems with Joint Detection

Intelligent reflecting surface (IRS) is a revolutionizing technology to boost the energy and spectrum efficiency by reconfiguring wireless propagation environment. In this letter, IRS is leveraged to improve the performance of the cell-edge user as well as the coordinated multi-point transmission (CoMP). Particularly, an uplink power minimization problem is formulated to jointly optimize the power allocation and the phase shifts in a two-cell IRS-aided non-orthogonal multiple access (NOMA) system with joint detection. To render the original problem tractable, the joint optimization problem of power allocation and phase shift is converted into a pure phase shift determination problem. Furthermore, a low-complexity method with closed-form solution is developed to address the transformed problem. It is shown by simulation that the power consumption of the proposed scheme is quite close to the lower bound and is less than those of various benchmarking schemes.