Peak-to-Average Power Ratio Reduction in OFDM Index Modulation Through Convex Programming

Orthogonal frequency division multiplexing (OFDM) index modulation (IM) is a new multi-carrier modulation where the sub-carriers have two states, active and idle, and the indices of the active sub-carriers carry information. Although showing many advantages over OFDM, OFDM-IM also inherits the high peak-to-average power ratio (PAPR) problem. In this letter, utilizing the signal feature of OFDM-IM, a high-efficient PAPR reduction method is proposed. Concretely, a small dither in the idle sub-carrier is introduced to reduce the PAPR, and the design of the optimal dither signal can be solved by the convex programming. Simulation results show that the proposed method can achieve a large PAPR reduction when a proper amplitude constraint on the dither signal is employed.