Ds-cdma Frequency-domain Equalization with Rls-based Channel Estimation

Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can provide a better downlink bit error rate (BER) performance of direct sequence code division multiple access (DS-CDMA) than the conventional rake combining in a frequency-selective fading channel. FDE requires accurate channel estimation. Recently, we proposed a pilot-assisted channel estimation based on the minimum mean square error (MMSE) criterion. Using MMSE-CE, the channel estimation accuracy is almost insensitive to the pilot chip sequence, and a good bit error rate (BER) performance is achieved. We also proposed a 2-step maximum likelihood channel estimation (MLCE) to further improve the estimation accuracy. However, the tracking ability is a problem in 2-step MLCE. In this paper, we propose a one-tap RLS-based channel estimation scheme for DS-CDMA with FDE. We evaluate the BER performance using one-tap RLS-based channel estimation in a frequencyselective Rayleigh fading channel by computer simulation. The BER performance using one-tap RLS-based channel estimation is compared with that using 2-step MLCE and pilot-assisted channel estimation with linear interpolation.