Performance of equalizers with dynamic length

In mobile communication systems, an equalizer can be used to counteract the distortion introduced by the channel. Because of the time varying property of the channel, an adaptive algorithm should be adopted at the equalizer. The LMS algorithm is a widely used adaptive algorithm whose performance is determined by the channel conditions, the SNR scenario and the length of the equalizer. The influence of the equalizer´s length on its performance is analysed. The results show that accurate control of the length of the equalizer can improve the performance of the system. An adaptive algorithm based on the LMS algorithm which can adjust the length of the equalizer according to the instantaneous channel conditions is proposed and simulation results show that this method can track even a very fast changing channel.