Decision-feedback blind adaptive multiuser detector for synchronous CDMA system

In this paper, we develop a blind adaptive multiuser detector for synchrono us code-division multiple access (CDMA) with a noise-whitening filter. The triangular structure of the noise-whitened model ensures complete resolutio n of detection ambiguities, To further improve the symbol error probability performance, we introduce decision feedback in our detector similar to the decorrelating decision-feedback detector (DDFD), thus forming the decision -feedback blind adaptive multiuser detector (DFBD), Simulations indicate th at the performance of the DFBD is very close to that of the DDFD in additiv e white Gaussian noise (AWGN) channels, In Rician fading channels, the DFBD can track the slowly varying channels well and has symbol error probabilit y performance approaching that of the DDFD, which requires the knowledge of users' energies. The blind adaptive and decision-feedback blind adaptive m ultiuser detectors proposed here do not, however, require that knowledge.