Performance Analysis of FFT-OFDM and DWT-OFDMover AWGN Channel under the Effect of CFO

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier based system that is selected to be used in the broadband wireless communication system. However, the main drawback considered for OFDM system is the Carrier Frequency Offset (CFO) which causes the Inter-Carrier Interference (ICI) that degrades the performance of the OFDM system. This paper discusses the performance of the system based on Bit Error Rate (BER) in the presence of CFO. For this, the estimation of CFO is carried over in both Discrete Wavelet Transform (DWT) OFDM and FFT OFDM for five different values of CFO (CFO = 0, 0.05, 0.1, 0.15, 0.2) in AWGN (Additive White Gaussian Noise) channel using the same procedure and their BER performance are simulated using MATLAB software. A comparative analysis on FFT-OFDM and DWT-OFDM systems is offered that shows that the performance given by DWT-based OFDM system is better in comparison to the FFT based OFDM system. BER results are simulated for BPSK, QPSK, 8-PSK, 16-PSK, 32-PSK modulations for both DWT and FFT based OFDM models. The analysis of MATLAB simulation clearly shows that the DWT-OFDM offers an improvement of 5-10 dB for the diverse order of modulations over AWGN channel.