Simulation of Adaptive Blind Multiuser Detector in DS-CDMA Wireless Communication

Abstract

Multiuser detection is the demodulation of signals of different users interfering with each other. This phenomena known as multiple access interference occurs mostly in code division multiple access (CDMA) systems. In this paper the study and analysis of the blind adaptive multiuser detection algorithm is achieved for directsequence code division multiple access (DS-CDMA) communication systems. The goal is to obtain multiuser detectors that require only knowledge of the signature waveform and timing of the desired user. Comparison is performed of the blind adaptive technique with the conventional detector (matched filter detector) or (M.F.D) in perfect power control and in the presence of the near-far effect. In the present simulation, the blind adaptive multiuser detection showed an excellent bit error rate as compared to the conventional detection with the same requirements. Also the blind detector showed an immunity towards the near-far problem. In this simulation the use of adaptive variable step size is used in contrast to the constant step size shows improvement in speed convergence and stability of the algorithm adapte