OFDM Peak-to-Average Power Ratio Reduction by Time-Frequency Processing

In this paper, we introduce a direct peak-to-average power ratio (PAPR) reduction approach for orthogonal frequency division multiplexing (OFDM) systems, termed time permutation and phase rotation (TPPR), which exploits the additional freedom degrees of time domain symbols in one timeslot to obtain additional PAPR reduction gains. This method divides OFDM symbols in frequency domain into subblocks and rotates each subblock phase with phase factors. Then these subblocks are transformed into time domain sequences by IDFT and permutations are performed among these subblocks in different symbols. For complexity reduction, two suboptimal schemes time shifting (TS-TPPR) and random selecting (RS-TPPR) are proposed. Simulation results show our methods can obtain significant PAPR reduction gains, and compared to multi-symbol SLM, RS-TPPR can provide better performance with the same complexity.