Max-Min Fairness of Multi-beam Multicast Based on MIMO-NOMA

With the help of massive multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA), multicast transmission can accommodate more users on the same spectrum resources and increase the capacity of the system. One limitation is that most studies usually focus on improving the system sum rate. However, because the quality of service of the wireless multicast group depends on the weakest user, it may cause unbearable rate loss to the weakest user. Unlike most existing literature, we focus on the rate of the weakest user to ensure successful communication and fairness of the whole system. This paper focuses on the requirement of ensuring the realizability of weak users and tries to analyze the minimum rate of the system to maximize it, by designing power allocation and digital precoding matrix, using convex optimization research to solve the problem. The simulation results show that the minimum rate of the system can be greatly improved, and the fairness of the system is better than other schemes after the beam digital precoding and power allocation. These results have great implications for our research.