Suppressing Interference and Power Allocation Over the Multi-Cell MIMO-NOMA Networks

Non-orthogonal multiple access (NOMA) can dramatically improves the spectral efficiency, while the cell-edge user's performance will be fiercely degraded due to inter-cell interference in the multi-cell NOMA networks. In this letter, we invoke interference alignment (IA) to resist the performance loss of the cell-edge users and propose a cooperative transmission scheme for the multi-cell NOMA networks. Then, we formulate an optimization problem in terms of joint multi-cell power allocation to seek an optimal transmission scheme. To solve the challenging nonconvex problem, the tight lower bound function and the logarithmic change of the variables are employed to convert the prime problem into a convex optimization problem, consequently obtaining a suboptimal solution through iteratively updating the lower bound. Finally, we demonstrate the efficacy of the proposed scheme through the numerical simulations.