An order-adaptive filter for channel estimation in DS-CDMA mobile systems

A novel adaptive filter for channel estimation in DS-CDMA mobile systems is proposed. When the maximum Doppler frequency changes, the method automatically adjusts the length of WMSA channel estimation filter to improve the performance considering both the noise removing property and the fading tracking property. We compare the SNR of the channel estimates and the BER performance between order-fixed WMSA filter and order-adaptive WMSA filter. The simulation results show that the optimal length of the filter is a function of the maximum Doppler frequency, and the BER performance is improved by using our order-adaptive filter compared to the traditional order-fixed WMSA filter.