A space-time decorrelating rake receiver for DS-CDMA communications over fast fading channels

This paper proposes a new space-time decorrelating RAKE (ST-DRAKE) receiver for CDMA systems in fast fading channels. It is based on the ST-DRAKE receiver previously reported by us (2002), which is a generalization of the DRAKE receiver originally proposed by Liu et al. (1999) for blind CDMA reception over frequency-selective fading channels. The performance of these traditional DRAKE CDMA receivers, which are based on slowly time varying channels, is significantly affected by fast fading channels. The proposed receiver employs a Kalman filter to estimate the impulse response of the fast fading channel so that the transmitted symbols can be estimated after coherent combining. Computer simulations show that the proposed receiver has comparable but slightly inferior performance to the space-time MMSE receiver.