Energy-Efficient Power Control for TDD MISO Systems

This paper addresses energy-efficient power control for time-division-duplexing (TDD) multiple-input-single-output (MISO) systems. Assuming ideal channel reciprocity, the beamforming at the transmitter (TX) is based on the estimated channel state information (CSI) obtained from the pilot signal of the receiver (RX). We define the energy efficiencies of the TX and the RX separately and study their energy efficiency region. In addition, we seek a power control scheme that can achieve all the points on the Pareto boundary of the energy efficiency region. We propose to maximize the weighted system energy efficiency, which is the data rate divided by the weighted sum of the power consumption at the TX and the RX. A method based on the quasi-concavity of the weighted system energy efficiency is developed to solve the problem. Simulation results show that the proposed power control can achieve all the points on the Pareto boundary of the energy-efficiency region by varying the weight.