A Modified ABC-PTS with Non-Uniform Phase Factor for OFDM Signal.

Time-domain OFDM (Orthogonal Frequency Division Multiplexing) signal has various different levels from many subcarriers in one frame which are fatal effect in the non-linear OFDM channel. Because of the signal distortion occurring at the output of non-linear power amplifier, the performance of system has failure. This issue is called that Peak to Average Power Ratio or PAPR which is the main issue of concern for OFDM system. One of the effective PAPR reduction technique known as partial transmit sequence (PTS) with non-uniform phase factors investigating between 0 and 2π was proposed to solve this issue which can suppress the PAPR value competently by clustering their data subcarriers in frequency-domain and multiplying data subcarriers in each cluster by non-uniform phase factors in time-domain after IFFT (inverse fast Fourier transform). However the computational complexity is increased in proportion to the increasing of cluster numbers. By carefully reducing the PAPR of time-domain OFDM signal with small computational complexity, this paper proposes a modified ABC (Artificial Bee Colony) with PTS (ABC-PTS) scheme which can reduce the PAPR of time-domain OFDM signal by applying non-uniform phase factor in the weighting factor sequences with small computational complexity of PAPR reduction process by performing the modified ABC algorithm. The simulation results in this paper can demonstrate that the proposed scheme outperforms approximate 0.4dB and 0.8dB over the original PTS for adjacent and interleaved respectively and approximate 3.2dB over the conventional OFDM at CCDF=10^-2 (Complementary Cumulative Distribution Function) with smaller computational complexity which is 19.14% approximately as compared with the original PTS. Moreover, the radix-2, radix-4 and split-radix DIF-IFFT (Decimation-in-Frequency IFFT) algorithms are employed to reduce the computational complexity which are approximate 50%, 62.5% and 66.67% for PAPR reduction process without affecting the optimum PAPR performance. [ABSTRACT FROM AUTHOR]