Energy Efficiency Maximization for MISO Systems with Total and Per-antenna Power Constraints

In wireless communications, the power of each antenna is typically constrained similar to the total power. In this paper, we consider a maximization problem of energy efficiency (EE) for multiple-input single-output (MISO) systems in the presence of both total and per-antenna power constraints. To solve this global non-concave optimization problem, we propose an iterative antenna selection and power allocation (IASPA) algorithm with two steps. In the first step, a set of optimal antennas are selected based on their channel gains. In the second step, by proving the concavity of this maximization problem of energy efficiency for fixed active antennas with respect to total power for transmission, we solve the power allocation by bidirectional search approach. Numerical results suggest that the proposed IASPA algorithm achieves the same performance as brute-force search and requires low computational burden.