Performance Assessment of Channel Estimation in Wavelet-based OFDM System
In a field of communication, OFDM has turned out as a sterling methodology. The basic system of OFDM comprises fast fourier transform (FFT), which computes the DFT of a source signal more effectively with faster computations. However, the OFDM system with this FFT has several drawbacks like lack of localization, higher error rates during high speed data rates and minimal spectral efficiency. To address these problems, wavelet based OFDM came into existence to replace the FFT with discrete wavelet transform (DWT). In this, an enhanced DWT-OFDM system with channel estimation is implemented to mitigate the execution of bit error rate (BER) values compared to that of FFT-OFDM. In addition, an equalization of channel also proposed under the environment of fading conditions like Rayleigh, Rician and additive white gaussian noise (AWGN). Moreover, it is essential to estimate a channel with more efficacy and sturdy against the scenario of time varying fading channel conditions. Extensive analysis of simulation experiments disclosed that the proposed system effectiveness over conventional FFT-OFDM system.
Keywords - Orthogonal Frequency Division Multiplexing, Discrete Fourier Transform, Fast Fourier Transform, Discrete Wavelet Transform, Least Mean Square, Recursive Least Square, Normalized Least Mean Square, AWGN, Rayleigh, Rician and Bit Error Rate.