Modified PTS based on Superimposed Training Sequence Method for PAPR Reduction of OFDM Signals with Different Subblocks

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is regarded as a promising technique for achieving high capacity in frequency selective fading channels. It is well known that OFDM signals have high peak-to-average power ratio (PAPR) and are thus not power efficient. High PAPR is caused by the large envelope fluctuations of the OFDM signal. High PAPR values lead to serious problems such as severe power penalty at the transmitter, which is not affordable in portable wireless systems where terminals are battery powered. Hence, Partial transmit sequence (PTS) scheme is an attractive solution to reduce PAPR without any distortion of transmitted signals. In the PTS scheme, one OFDM symbol is partitioned into disjoint subblocks, and each subblock is multiplied by a phase factor to generate OFDM signals with low PAPR. In the ordinary PTS scheme, the computational complexity increases extensively with the number of subblocks. In this paper, modified PTS based on superimposed training sequence method reduces the PAPR of OFDM signals, by different subblocks and it has low computational complexity has been presented. Simulation results demonstrate that all the training sequences in the proposed scheme have superior performance with different subblocks in the OFDM system.