Blind channel identification for third-generation wideband CDMA communication systems

Abstract

CDMA communication employing coherent detection with pilot symbol-assisted channel estimation significantly outperforms non-coherent detection. Pilot symbol-assisted channel estimation has been adopted in the development of the third-generation wideband CDMA mobile communication system. However, the performance of the pilot symbol-assisted channel estimation is limited in a fast fading environment because only a few pilot symbols are inserted in each frame of received data in the third-generation wideband CDMA system. In this paper, a blind channel identification method is proposed based upon the Cross-Relation Method of Xu, Liu, Tong, and Kailath, in order to reduce the need for pilot symbols in coherent detection. First, an equivalent time-invariant single-input multi-output system is created for the de-spreaded signals through employing multiple antennas at receiver site. Second, the Cross-Relation Method is applied to the equivalent linear time-invariant single-input multi-output-channel model to blindly identify the channel. Simulations are performed to evaluate the blind channel identification method's applicability to third-generation wideband CDMA.