ABSTRACT
To track a desired signal-to-interference-plus-noise ratio (SINR) that allows for higher system throughput and better link quality in an interference-limited wireless communication system, a feedback power controller is designed to obtain optimal SINR tracking control. In this chapter, we propose the multi-objective (MO) H2 /H∞ optimal power control for interference-limited wireless systems to provide quality solutions for both objectives. The considered multi-objective H2 /H∞ power tracking control is complicated in nature, and an equivalent formulation that minimizes the upper bounds of both objectives is proposed. Furthermore, the resulting constraints for the MO H2 /H∞ power control problem are transformed to three linear matrix inequalities, leading to a LMI-constrained MO problem. By combining the LMI toolbox in MATLAB with an evolutionary search algorithm, a set of H2 /H∞ solutions called Pareto optimal solutions can be obtained and a particular solution can be selected based on the tradeoff determined by the system designer. Finally, to illustrate the proposed design procedure, several numerical simulations are provided for a typical interference-limited wireless system, that is, a direct-sequence code division multiple access (DS-CDMA) cellular system. Simulation results demonstrate that the optimal tradeoff can indeed be achieved by the proposed MO H2 /H∞ power control.
