Adaptive Array In The Application Of Code Division Multiple Access (cdma)

In direct sequence code division multiple access (DS-CDMA) communications, blind signal detection and interference cancellation are the important methods to increase system capacities. Using array signal processing and adaptive detection technologies at the base station can efficiently improve the receive? s ability to suppress interference, achieve higher cell capacities and enhance communications quality.The researches in this paper focus on the multiuser detection in code division multiple access (CDMA) and array signal processing. The main contents are as follows:The paper makes some studies on generalized sidelobe canceller (GSC) . A new technique for DS-CDMA signal detection schemes is proposed, by using the structure of generalized sidelobe canceller, fast optimization is achieved based on the minimum-output-energy criterion. By restraining the norm of the weight vector, robust multiuser access interference cancellation is achieved. Furthermore, the RAKE technique is used to improve the performance of the receiver in Rayleigh fading channels.The paper makes some researches on training symbol-assisted least-mean-square (LMS) algorithm. It presents a DS-COMA multiuser interference suppression receiver with a training symbol-assisted coherent adaptive array. Finally, simulations are carried to verify that this receiver has good performances.The paper proposes a DS-CDMA multiuser interference suppression receiver with a blind decision-directed least-mean-square (LMS) algorithm array. It uses two methods based on matched filter and on fast dispreading filter optimization. Simulations are carried to verify these two receiver?s performances.The paper makes some studies on subspace tracking algorithm. It brings up a new DS-CDMA multiuser interference suppression receiver with a subspace tracking adaptive array.