Peak-to-Average Power Ratio Analysis and Reduction in Transform Domain Communication System

Transform domain communication system (TDCS) is a potential candidate for cognitive radio (CR). It is immune to the interception and has the characteristics of high spectral utilization. Nevertheless, large peak-to-average power ratio (PAPR) of the time domain signal inherently makes TDCS particularly sensitive to nonlinear distortion caused by the high power amplifier (HPA). In this paper, we analyze the statistical distribution of PAPR, derive the complementary cumulative distribution function (CCDF) and put forward an algorithm to reduce PAPR by adding a power controllable signal on the transmit signal in TDCS. This algorithm is acquired by modifying the tone reservation (TR) algorithm in orthogonal frequency division multiplexing (OFDM). This algorithm provides an ability to fast respond to the spectrum environment and a lower computation complexity compared with approximation projection onto complex sets (APOCS). Simulation results reveal that the proposed algorithm reduces PAPR effectively without extra loss in bit error rate (BER).