PAPR Reduction in OFDM by using Companding Technique

Abstract

Orthogonal frequency division multiplexing (OFDM) is a method performed in Long Term Evolution (LTE) systems to accommodate various users within a specified bandwidth .one of the advantage of the OFDM is that, it divides a channel into several narrow orthogonal bands and also makes them non interfering with each other. Drawback of the OFDM is PAPR. OFDM signals passes through high power amplifiers there will be some losses that occur which leads to decrease in the efficiency of the system. To overcome the problem of PAPR we have various methods, partial transmit sequence is one such method for reduction of PAPR. Cyclic Shifted Sequence (CSS) is a method which is an extension to the PTS method. in the CSS, shift value selection plays a major role in the proposed method along with the CSS scheme with shift value(SV) selection we add another block called as Companding as a result we get better results.