A Low Complexity Iterative SLM-OFDM for SHF band applications

Abstract The transmitted Orthogonal Frequency Division Multiplexing signal in systems such as Wireless LAN, Mobile WiMAX, Digital Video Broadcasting (DVB) operating in the Super High Frequency (SHF) band suffers from high Peak to Average Power Ratio. This is reduced in Selective Level Mapping (SLM)approach but at the expense of increased complexity. In this paper, we propose iterative selective level mapping based on an orthogonal phase sequence set for PAPR reduction with reduced computation complexity. The Golay Complementary pair is used as basis to generate the phase sequence set. Analysis of the aperiodic properties of individual phase sequence and the entire phase sequence set is carried out. It is suggested that mean-square value of auto correlation be an additional measure to choose phase sequence set. Simulations are carried out to assess the PAPR and complexity reduction achieved. The proposed phase sequence set achieves a 1.2 dB and 2.4 dB PAPR improvement over conventional SLM and OFDM respectively for maximum of 16 candidate signals at iterative threshold of 6 dB. The computational complexity reduction achieved is 59%.