A Peak Power Reduction Method with Reduced Inter-Signal Interference for OFCDM Signal

A problem with the OFCDM (orthogonal frequency and code division multiplexing) system is that PAPR (peak to average power ratio) of the signal becomes high. In this paper, we propose a novel peak reduction method which suppresses the inter-signal interference caused by peak power limitation for OFCDM signal. In the proposed method, peak power is reduced by adding the peak reducing signal generated with peak components detected by soft-clipping function. At the receiver, the inter-signal interference is compensated by estimating the peak components removed at the transmitter from the received signal. Performance of a total system including modulation, peak-limiter, predistorter, a model of 2 GHz class A/B power amplifier and the receiver is investigated by computer simulation. Computer simulation results show the peak power reduction performance is improved about 1.4 dB as compared with that of the conventional PRSA (peak reducing signal addition) method.