Optimal constellation distortion for PAR reduction in MIMO-OFDM systems

One of the main problems with orthogonal frequency division multiplexing (OFDM) modulation is the high peak-to-average-ratio (PAR) of the transmitted time-domain signal. Optimally distorting the transmitted constellation for peak reduction in OFDM systems was introduced and shown to be a convex optimization problem. This work advantageously extends this approach to multiple-input multiple-output (MIMO) systems. While the problem is still convex, solving the problem using standard convex optimization techniques quickly becomes computationally prohibitive for a large number of tones and/or antennas. This paper therefore also proposes solving the optimization problem using an interior-point method (IPM) based on the conjugate-gradient (CG) algorithm.