MMSE-DFE Equalizer for Discrete Wavelet Packet Transform Based Wireless Communication System for Channel Equalization

Abstract

Discrete Wavelet Packet Transform (DWPT) based Orthogonal Frequency Division Multiplexing (OFDM) system has been suggested and it has been the area of study for many researchers over the years. The major benefit of using DWPT, it does not require Cyclic Prefix (CP) which improves the spectral efficiency of OFDM based communication systems. In this article, DWPT based OFDM is used and for equalization, Decision Feedback Equalizer (MMSE-DFE) is proposed. Equalization is a key factor in wavelet-based communication systems. Non-linear MMSE-DFE is applied to the system for DWPT based OFDM (WOFDM) and compared with linear Minimum Mean Squared Error (MMSE) and Zero Forcing (ZF) equalizers. The system is simulated for Finite Impulse Response (FIR) channels. The noises are used in simulation are Additive White Gaussian Noise (AWGN) and impulse noise. There is a clear improvement of system’s bit error rate (BER) for MMSE-DFE in comparison with MMSE and ZF equalization techniques in addition of noise while looking at simulation results.