Blind iterative separation of CDMA signals by nonlinear independent component analysis

In this paper we study the use of projection pursuit[12] and independent component analysis[2] in blind demodulation of CDMA signals in the presence of high multiple access interference. The blind single-user receiver is assumed to be unaware of the signals transmitted by co-channel users. Conventionally, linear MMSE receivers have been applied to solve the problem[10]. However, it is well known that linear receivers are suboptimum for the given problem[16]. In this paper we propose a blind nonlinear multiuser receiver, where signal (code and bit) estimates are refined iteratively for the interfering users. This leads to rapid system identification and detection with performance superior to linear MMSE receivers.