A new adaptive interference cancellation receiver
A new kind of linear adaptive parallel interference cancellation receiver for coherent demodulation in asynchronous code division multiple access (CDMA) systems is considered. The proposed linear adaptive receiver is a little more complex than the standard single-user receiver consisting of filter banks with constant coefficients, but achieves essential advantages with respect to multiple access interference (MAI) and near/far effect. It need no more knowledge of users than the conventional receiver, and the receiver is trained by a known training sequence prior to data transmission and continuously adjusted by an adaptive algorithm during data transmission. The computational complexity of the receiver increases linearly with the number of users. The structure of the receiver is all feedforward and the system is more stable. The receiver can also be combined with the smart antenna and obtain better performance. The proposed receiver is tested by simulations over a channel with multiple access interference and additive white Gaussian noise.