Fractionally Spaced Channel Estimation for Synchronous DS-CDMA Downlink with Aperiodic Spreading Code
非周期扩频的同步CDMA系统下行信道的分数阶间隔信道估计

Synchronous Code-Division Multiple-Access (CDMA) techniques possess intrinsic protection against co-channel interference when orthogonal codes are used. However, in the presence of multipath propagation, the signals lose their orthogonality property, leading to increased cross correlation. In these cases, channel estimation may be needed in order to improve detection. The former algorithms for estimating the channel response of CDMA system are used for signal sampled with chip rate. The received signal sampled in chip rate does not satisfy the Nyquist theory and the channel may be not a minimum-phase system that the former algorithms do not work. An algorithm for fractionally spaced channel estimation of a synchronous CDMA system is proposed that uses aperiodic spreading code. Simulations demonstrate the performance of proposed algorithm.