Enhancing Spectral Efficiency for Massive MIMO Systems Using Power Allocation Approaches

Massive Multiple Input Multiple Output (MIMO) is recognized as one of the next-generation technologies of wireless communication which provides a high Spectral Efficiency (SE). Due to the dense distribution of users in the communication cells, supporting massive connectivity, low latency, higher SE and Power Efficiency (PE) have been recognized as the main challenges of the next-generation wireless networks. An appropriate strategy for allocating power to different users is one of the ways to enhance the SE and PE. In this paper, to enhance SE of the massive MIMO system with hybrid precoding and based on the Discrete Fourier Transform (DFT) processing, two methods for allocating power to users are proposed. In the first method, in order to enhance the SE of users with poor channel conditions, we assign a constant power coefficient to each user according to the user’s channel conditions. In the second method, we allocate the optimal power coefficients to users by using the Particle Swarm Optimization (PSO) algorithm. Also, we evaluate the effect of the number of radio frequency (RF) chains, the Signal to Noise Ratio (SNR) and the number of users on the SE of the system. Simulation results show that both proposed power allocation methods improve the total SE of the system.