Performance analysis and optimization of ergodic secrecy rates for downlink data transmission in massive MIMO-NOMA networks

In this paper, we investigate the secrecy performance of a massive MIMO NOMA network. Specifically, we demonstrate a detailed training process in the network and derive downlink ergodic secrecy rates of legitimate users. In order to gain system’s insights, discussions on secrecy performance of the network in two special cases, i.e., large number of antennas and high transmit power at the BS, are provided. Furthermore, from the analysis, an optimization to maximize the users’ minimum secrecy rate in each NOMA cluster is proposed to aid the weak users’ secrecy performance. The correctness of our analysis and the efficiency of the proposed are confirmed through computer simulations.