A Unique Wavelet-based Multicarrier System with and without MIMO over Multipath Channels with AWGN

Abstract

Recent studies suggest that multicarrier systems using wavelets outperform conventional OFDM systems using the FFT, in that they have well-contained side lobes, improved spectral efficiency and BER performance, and they do not require a cyclic prefix. Here we study the wavelet packet and discrete wavelet transforms, comparing the BER performance of wavelet transform-based multicarrier systems and Fourier based OFDM systems, for multipath Rayleigh channels with AWGN. In the proposed system zero-forcing channel estimation in the frequency domain has been used. Results confirm that discrete wavelet-based systems using Daubechies wavelets outperform both wavelet packet transform-based systems and FFT-OFDM systems in terms of BER. Finally, Alamouti coding and maximal ratio combining schemes were employed in MIMO environments, where results show that the effects of multipath fading were greatly reduced by the antenna diversity.

Effects of Transmit Diversity on a Discrete Wavelet Transform and Wavelet Packet Transform-based Multicarrier Systems

“…Any orthogonal wavelets (e.g. Daubechies, Symlet, Coiflet) will show the same performance in AWGN and Rayleigh channels [23]. The answer to the question of the effect of filter order in orthogonal wavelets is addressed later in the discussion.…”

“…Figure 12 shows a comparison between three different orthogonal wavelet families. It has been suggested in [23] that all orthogonal wavelets perform alike which is true in the case of BER performance both with and without beam-forming but the system processing time considerably varies between them. In this study, it was noticed that the processing time of the Daubechies wavelet filters of order 8 had the fastest processing followed by the Symlet filters of order 8 and the Coiflet filters of order 5 had the slowest processing.…”

MIMO Wavelet Transform using Optimized Successive Interference Cancellation

“…Wavelet-based systems can provide all the conventional advantages of OFDM systems and can help improve the PAPR, sensitivity to carrier frequency timing offset and overall Bit Error Rate (BER) performance of the system [3]. The ISI produced in the wavelet-based multi carrier system (MCS) can be divided among different wavelet symbols, thus becoming easily correctible at the receiver.…”