ADAPTIVE DETECTION FOR DS-CDMA

A review of adaptive detection techniques Sor direct-sequence code div ision multiple access (CDMA) signals is given. The goal is to improve CDMA system performance and capacity by reducing interference between users. The techniques consider ed are implementations of multiuser rec eivers, Sor which background material is given. Adaptive algorithms im prove the feasibility of such receivers. Three main forms of receivers are considered. The minimum mean square error(MMSE) receiver is descr ibed and its performance illustrated Numerous adaptive algorithms can be used to implement the MMSE receiver; including blind techniques, wh ich eliminate the need for training sequences. The adaptive decorrelat or can be used to eliminate interference from known interferers, thoug h it is prone to noise enhancement. Multistage and successive interfer ence cancellation techniques reduce interference by cancellation of on e detected signal from another: Practical problems and some open resea rch topics are mentioned. These typically relate to the convergence ra re and tracking performance of the adaptive algorithm.