This thesis presents the blind adaptive decorrelating decision-feedback detector (BADF) that uses the blind adaptive algorithm for reducing the complexity of the decorrelating decision-feedback detector (DDFB). The BADF has been used to eliminate multiple access interference (MAI) at the base station in the tri-rate CDMA system. Bootstrap algorithm was used at feed forward filter to eliminate some interferences from high-rate and medium-rate users, and the bootstrap algorithm was used to cancel the remaining MAI at the feedback filter. A transmitting synchronous system is considered over an AWGN channel. The blind adaptation does not have to send the training sequence, so the bandwidth utilization is good. From the simulation result, the BADF can reduce time delay for high-rate users and keep the good performance for low-rate users. Moveover, the BADF does not find the inverse cross-correlation matrix of the code, so it can reduce the complexity of the receiver.
