Optimal transmit power and antenna selection to achieve energy-efficient and low-complexity in 5G massive MIMO systems

This paper investigates joint antenna selection and optimal transmit power in multi-cell massive multiple-input multiple-output (MIMO) systems. The pilot interference and the number of activated transmit antenna selection plays an essential role in maximizing the energy efficiency (EE). We derived the closed form of maximal EE with complete knowledge of large-scale fading with maximum ratio transmission (MRT) while accounting for channel estimation and eliminated pilot contamination when M→∞. We investigated joint optimal antenna selection and optimal transmit power under minimized reuse of pilot sequences based on a novel iterative low-complexity algorithm for Lagrange multiplier and Newton’s methods. The two scenarios of achievable high data rate and total transmit power allocation are the critical design to the performance maximal EE. To analyze exact power consumption (PC), we propose new PC for each antenna based on the transmit power amplifier and circuit PC. The simulation results show that maximal EE could be achieved using the iterative low-complexity algorithm based on the reasonable maximum transmit power when the noise power was less than the power received pilot. The proposed low-complexity iterative algorithm offers maximum EE by repeating a minimized pilot signal until the optimal antenna selection and transmission power are achieved.