AN EQUALIZATION ALGORITHM FOR WAVELET PACKET BASED MODULATION SCHEMES

Recently, a considerable amount of attention is being given to the use of wavelets for modulation and equalization. In this correspondence, we present an equalization algorithm for a wavelet packet-based, modul ation scheme. A nonideal channel can he divided into a set of bands, w here each band can be approximated as a simple attenuation and delay c hannel, Wavelet packets, being narrowband and orthonormal, are a natur al choice for realizing such bands. Thus, if the data sequence is used to modulate a set of wavelet packets, the equalization problem reduce s to that of determining the delay introduced by the channel for each of the wavelet packets (if the wavelet packets do not overlap in the f requency domain) and possibly a change of sign in the decoded symbols, The attenuation affects the SNR at the output of the demodulator, whi ch in turn affects the correct decoding of the transmitted symbols, A minimum square variance algorithm for adaptively choosing the delay ha s been proposed. The algorithm uses the statistics of the received seq uence to pick the appropriate delay, Simulations have been conducted t o study the performance of the equalization algorithm and compare it w ith that of DFT-based DMT scheme.