1 Sadaf Nadeem

Sadaf Nadeem, Jammu Kashmir, Manish Sabraj
2018 Manish Sabraj International Journal of Electronics, Electrical and Computational System IJEECS ISSN 2348-117X   unpublished
Communication has got lot of changes regarding the transmission technique and demand of high data rate services as the new technologies are introduced .Single carrier system being switched to multicarrier system for improved transmission technology. Orthogonal frequency division multiplexing (OFDM) is one of the multicarrier systems which form the basis to handle number of subcarrier. Although OFDM has its own one of the disadvantage which degrades the system performance. Peak to average power
more » ... atio is major drawback in OFDM which is introduced due to phase and amplitude distortion among subcarrier. In this paper, a collaborative strategy is proposed to reduce the PAPR by transforming the signal through selective mapping and clipping process due to which the overall system performance is improved. KEYWORDS: Peak to average power ratio (PAPR), Bit error rate (BER), Orthogonal Frequency Division Multiplexing (OFDM), Inverse Fast Fourier Transform (IFFT), SLM INTRODUCTION With the ever growing need of this generation the demand of high speed communication is at utmost priority. Single carrier system is replaced by multicarrier system to avoid the degradation in system performance In single carrier system the whole bandwidth is used while in multicarrier system the available bandwidth is divided into many sub carriers. Various multicarrier systems are introduced like Frequency division multiple access (FDMA),Code division multiple access (CDMA), Time division multiple access (TDMA) which provide high data rate services but suffer from problems like attenuation, inter symbol interference (ISI) and multipath fading. OFDM is one of the multicarrier modulation technique used to provide high data rate services and provide immunity to multipath fading which overcome the limitation of other multicarrier system. In this system, the available frequency range is divided into number of low rate subcarriers. Due to which each sub carrier get smaller bandwidth as compared to carrier in single carrier system. OFDM is the basis of all 4G communications and widely used in many applications like Digital audio broadcasting (DAB), Digital video broadcasting (DVB), Long term evolution (LTE) and much more[3][16]. In OFDM system, time and frequency synchronization, carrier frequency offset (CFO),Peak to average power ratio and channel estimation are the disadvantages. But peak to average power ratio is the main drawback which limits the demand of high data rate services. When all subcarrier are at same phase and amplitude reach to receiver side then the signal envelope is increased that lead to increased peak to average power ratio. So the power amplifier (PA) drives in saturation region which degrades the system efficiency. To overcome the problem various techniques has been proposed, but each technique has its own disadvantage [1][2][9][12]. The remainder of this paper is organised as follows: In background work discussed the literature review about various techniques to reduce the peak to average power ratio in OFDM. The basic principle of OFDM and the