Distributed power allocation for the downlink of a two-cell MISO-NOMA system

In this paper, we investigate the distributed power allocation algorithm for the downlink of a two-cell multiple input and single output non- orthogonal multiple access (MISO-NOMA) system. The problem targets at minimizing the total power consumption of the base stations (BSs) while taking into consideration each user's data rate requirement. A distributed power control algorithm is devised. During each iteration, the BS updates the transmit power of its attached users according to the link gain vector and the inter-cell interference plus noise value at the users. For some special cases, we show that the proposed algorithm is guaranteed to converge to a unique fixed point that could be an optimal solution based on Yate's power control framework. Furthermore, some modifications are made for the iterative algorithm to enhance the convergence performance of the instances with feasible solutions. Simulation results demonstrate that the designed power allocation strategy can significantly improve system performance over conventional orthogonal multiple access (OMA) counterpart in terms of total transmit power and outage probability.