MULTI-USER DETECTION TO ENHANCE THE CAPACITY OF W-CDMA BASED ON THE CONJUGATE GRADIENT METHOD

摘要

Multiple users communicate with individually-assigned codes on a single radio carrier frequency in a DS-CDMA system. Mutual interference among codes limits the capacity of the system. Conventional detectors of receivers are designed for a single-user neglecting the mutual interference. Multi-user detection is expected to enhance the capacity by removing the interference factors. In this paper, a new scheme is proposed corresponding to solving a huge matrix equation under multiple access interference (MAI) environments. This scheme is obtained by the mathematical approach to solve a huge matrix equation. The modeling of multiuser detection is shown, and the algorithm is given based on mathematical approach: the Conjugate Gradient Method (CGM). The characteristics of the proposed scheme are evaluated with comparison to the conventional single-user detector. The proposed scheme has been shown to be three times in capacity against single user detection with reduced complexity comparing conventional technologies based on serial and parallel configurations.