Transformed Domain Linear Equalisers using Discrete Gabor Transform

The concept of transform domain adaptive equalizer is introduced in this paper. An ideal equalizer should offer minimum synchronization time. This can be achieved if the equalizer takes minimum sampling or training. This objective can be achieved if the transformed domain equalizer is used instead of the time domain one. In the present investigation discrete Gabor transform (DGT) is selected to be used in the front end of the transformed domain equalizer. Its convergence performance and minimum mean square error are obtained through simulation and is compared with those of LMS and DFT based equalizers. It is observed that the new transformed domain equalizer provides superior performance compared to the time domain one however the performance is equivalent to that of other orthogonal transformed based equalizers. The British broadcasting channel is taken for experiment. The SNR is set at 20dB and 15 dB in first and second case. The MSE was obtained (plotted) after averaging 500 independent runs each consisting 3000 iterations. Six different channels were studied. The best performance was obtained in case of Gabor transform domain equalizer in channel 6 and 3. The SNR is considered as 15 dB. . It gave better convergence rate and lower MSE floor. For lower noise level at SNR 20 dB the same result was obtained