Globally optimal tradeoff curves for OFDM PAR reduction [peak-to-average power ratio]

Abstract

This paper describes an efficient convex optimization technique for computing the globally optimal tradeoff curves between OFDM peak-to-average power ratio (PAR), constellation error, and free carrier power. The OFDM system designer can select a suitable PAR reduction method by comparing the achieved performance of various algorithms with these optimal tradeoff curves. Simulation results are presented for the 802.11a/g WLAN standard. The power wasted in the free carriers can be substantially reduced by taking advantage of the allowed constellation error and by backing off 1 dB from the globally minimum PAR. A convex interior-point method reaches the desired tradeoff point within two iterations for both QPSK and 64-QAM.