Delay estimation and data detection in long-code DS-CDMA system

In this paper, we aim at solving the problem of joint delay estimation and data detection of the orthogonal modulated signals in the asynchronous DS-CDMA system employing aperiodic long spreading codes over fading channels. The general system requirement of low error rate in data demodulation necessitates the reliable synchronization mechanisms. Synchronization of CDMA signals with long spreading codes is a more challenging task than that of CDMA signals with short spreading codes. In this work, two algorithms are introduced to perform acquisition and tracking of orthogonal modulated signals with long spreading codes, followed by data detection. The numerical results show that when applying to the asynchronous system with random propagation delays, the proposed algorithms approximate the performance that is attainable in the synchronized and chip-aligned system.