Cubic metric reduction in OFDM systems by using convex optimization

Orthogonal frequency division multiplexing (OFDM) has been adopted by several communication standards. A major disadvantage of OFDM is the large envelope fluctuations which cause the degradation of system performance. Peak-to-average power ratio (PAPR) is a well-known measure for the envelope fluctuations. However, recently, another metric, known as cubic metric (CM), has been attracting increasing attention since it can predict the power de-rating of power amplifier more accurately. In this paper, our analysis shows that minimizing CM, subject to the in-band distortion and out-of-band radiation, can be formulated as a convex optimization problem. By solving this convex problem, the minimum CM satisfying the given requirements can be obtained. Simulation results verify the effectiveness of the proposed method.