Nonlinear Companding Technique in OFDM System with Different Modulation Scheme

I KoilPandi, N Vignesh Ram

Abstract


The major drawback found in OFDM is high PAPR (Peak to Average Power Ratio). The various methods that are used to reduce the high PAPR are: Coding, Clipping, m- Law, Selective Mapping (SLM), Partial Transmit Sequence (PTS) and Exponential Companding (EC) etc. However these PAPR reduction techniques have some disadvantages, such as Higher Modulation Order, Degradation of the BER and SNR performance, increasing of Average Power etc. A new Nonlinear Companding technique is proposed which aim at compressing the large amplitude signals and at the same time maintaining the average power constant. The proposed scheme is to be implemented for different modulation scheme (BPSK, DPSK, QAM etc). The BER performance is to be evaluated and compared by implementing the Nonlinear Companding technique in the basic OFDM system.

Keywords


Orthogonal Frequency Division Multiplexing (OFDM), Peak to average Power Ratio (PAPR), Selective Mapping (SLM), Partial Transmit Sequence (PTS) , Exponential Companding (EC), Bit Error Rate (BER).

References


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