Peak-to-Average Power Ratio Reduction of OFDM signals Using Improved PTS Scheme with Low Computational Complexity

Abstract

In wireless communication, parallel transmission of symbols using multi carriers is applied to achieve high efficiency in terms of throughput and better transmission quality. Orthogonal Frequency Division Multiplexing (OFDM) is one of the techniques for parallel transmission. It effectively mitigates the effect on performance due to Intersymbol Interference and delay spread caused by wireless medium. However high peak to average power ratio (PAPR) is a major demerit of OFDM system. High PAPR leads to increased complexity of circuit and reduced efficiency of RF amplifier. Partial Transmit Sequence (PTS) is one of the most promising techniques for PAPR reduction. In conventional PTS scheme the computation of optimal phase factors necessitates exhaustive searching of all possible and allowable phase factors, this leads to exponential increase of computation complexity in terms of complex additions and multiplications as number of subblock increases. In this paper by exploiting correlation among various candidate phase factors a novel scheme is proposed here which reduces the computation complexity by tremendous margin and at the same time maintaining same PAPR reduction as conventional PTS scheme. OFDM signal Implemented here complies with IEEE 802.11 a standard.