Performance of SLM and TR method based on Efficiency for PAPR reduction in OFDM systems Gaurav M Dabade Research Scholar, Department of Electronics & Telecommunication, Dr. D.Y. Patil College of Engineering & Technology, Kasaba Bawada, Kolhapur, Maharashtra, India. Dr. A.N. Jadhav Professor & Head of Department, Department of Electronics & Telecommunication, Dr. D.Y. Patil College of Engineering & Technology, Kasaba Bawada, Kolhapur, Maharashtra, India. Abstract In this paper, we are focusing on the basic OFDM system performance w.r.t Signal-to- Noise Ratio (SNR), Bit Error Rate (BER) and throughput. Further, we have simulated the Peak-to-Average Power Ratio (PAPR), which is severe drawback of OFDM, with PAPR reduction methods such as Selected Mapping (SLM) and Tone Reservation (TR) [1]. We have compared SLM and TR methods on the basis of CCDF and Transmitted Power Efficiency. The simulation results are based on Cumulative Complementary Distribution Function (CCDF) parameter along with the transmitted power efficiency [2]. From the simulation results we can say that the reduction in PAPR through SLM is better than TR as well as the SLM shows outstanding efficiency during this simulation. Keywords: OFDM, BER, PAPR, Tone Reservation, Selected Mapping, Transmission Efficiency. Introduction Orthogonal frequency division multiplexing (OFDM) is becoming the chosen modulation technique for wireless communications. OFDM can provide large data rates with sufficient robustness to radio channel impairments. The separation of the subcarriers is theoretically minimal such that there is a very compact spectral utilization. Multipath generates two effects: frequency selective fading and inter- symbol interference (ISI). The most important disadvantage of OFDM systems is that highly linear RF amplifiers are needed. When N signals are added with the same phase, they produce a peak power that is N times the average power. In order to avoid nonlinear distortion, highly linear amplifiers are required which cause a severe reduction in power efficiency [1]. In order to reduce PAPR, we have proposed Selected Mapping (SLM) [3] and Tone Reservation (TR) [4][5] methods. Throughput Performance of OFDM System The OFDM throughput simulation is shown in Fig.1. We can see that throughput of QPSK is having overall higher throughput. By observing the simulation results of higher modulation schemes, we have considered QPSK modulation method for the further simulation. Figure 1: Throughput Performance of OFDM Schemes Peak-to-Average Power Ratio The Peak-to-Average Power Ratio is the result of the variations of high peaks of the sub-carriers in OFDM spectrum. A large PAPR increases the complexity of the analog–to–digital and digital–to–analog converter and reduces the efficiency of the radio – frequency (RF) power amplifier. Presence of large number of independently modulated sub- carriers in an OFDM system the peak value of the system can be very high as compared to the average of the whole system [1]. International Journal of Engineering Research and Technology. ISSN 0974-3154 Volume 10, Number 1 (2017) © International Research Publication House http://www.irphouse.com 838