Implementation of a Single IFFT Block based Partial Transmit Sequence Technique for PAPR Reduction in OFDM

Abstract

The current trends in wireless industry like IEEE 802.11a/g/n, IEEE 802.16e are based on OFDM which is highly promising in terms of higher data rates & better immunity to frequency selective fading. However OFDM is limited by high PAPR. High PAPR causes nonlinear distortion in the signal & hence results in intercarrier interference & out-of-band radiation. To combat the effect of high PAPR several PAPR reduction techniques have been devised. All these techniques have to strike a tradeoff among computational complexity, PAPR reduction performance, BER performance & redundancy. PTS technique provides a very effective PAPR reduction with no limit on the maximum number of subcarriers. But the technique suffers from very high computational complexity. Hence authors have tried to modify the technique so that the complexity is reduced significantly without affecting PAPR reduction performance. This dissertation is extensively based on PTS & in this course limns a novel approach which offers better PAPR reduction & significantly reduces the algorithmic complexity with respect to the original technique. The multiple numbers of IFFT blocks has been replaced by a single block; the parallel processing has been replaced by serial processing. The complexities & PAPR reduction performance of the modified & the original techniques have been compared.Furthermore the proposed technique has been emulated in a memory & power constrained environment on C6713DSK with TMS320C6713 processor using real signal input. The emulation results have been analyzed & it has been observed that the emulated PAPR values are at par with simulated ones. To check the SER performance of the technique, the receiver has been simulated as well. The transceiver channel model has been simulated & the SER performance of OFDM system with Single IFFT block PTS has been compared with that of OFDM without any reduction technique. The results show that the PAPR reduction technique does not affect the SER performance.