A Majorization–Minimization Approach for Reducing Out-of-Band Radiations in OFDM Systems

This letter is concerned with the reduction of the out-of-band (OOB) components in spectrum of orthogonal frequency division multiplexing (OFDM) systems. We propose an efficient method to obtain a phase sequence that is required in a phase adjustment algorithm, an algorithm which reduces the OOB components by employing proper phase shifts in OFDM symbols. The proposed method is based on the majorization-minimization technique, and converges to stationary points of an NP-hard design problem (under some mild conditions). Simulation results illustrate that the proposed method outperforms its counterparts in view of the solution quality as well as the computational complexity.