Computational structures for blind long-code WCDMA receivers

Long-code wideband CDMA receivers are for computational reasons usually based on simple matched-filter techniques, and hence suffer from multiaccess interference. To mitigate this problem, we propose computationally efficient decorrelating RAKE and MMSE receivers for the uplink of long-code CDMA systems. The decorrelating matched filter eliminates multiaccess interference by code matrix inversion. Channel parameters and data symbols are then estimated jointly via rank-one decompositions. The feasibility of the proposed schemes hinges upon their efficient implementation in terms of time-varying state space realizations, with a complexity comparable to that of the conventional RAKE receiver.