A novel adaptive channel estimation method in WCDMA system based on weighed least squares

Rayleigh fading channel estimation using time multiplexed pilot symbols in WCDMA system is considered. The WCDMA uplink signal model is established. Considering that channel parameter estimation in the pilot symbols which are far away from or near to data symbols have different effects on channel parameter of data symbols, weighted least square method is proposed to estimate channel parameter of data symbols. A novel adaptive channel estimation method based on weighted least squares (AWLS) is presented in this paper to meet simultaneously the needs of high speed, low speed, medium speed and varying-speed and the weighed combination function is introduced to solve this problem. Weight factor is determined by channel changing rate or maximum Doppler frequency. The method of the channel changing rate estimation is proposed in this paper and it has many advantages, such as small calculation and robust characteristic. The simulation results reveal that AWLS can track and estimate channel parameter of data symbol and RAKE receiver with AWLS method can perform well under high speed, medium speed, low mobile speed and varying-speed.