Low complexity receivers for CDMA communications in frequency-selective channels

A number of studies show that multiuser detection in CDMA communications can be performed blindly even in a frequency-selective fading environment. However, the computational cost of these blind approaches is magnitudely higher than that of adaptive MMSE receivers which require knowledge of the desired user´s signature waveform. The problem is alleviated by Tsatsanis and Bora (see IEEE Transactions on Signal Processing, 1997) where a low complexity blind algorithm is proposed at the expense of reception performance. In this paper, we present a totally blind adaptive method which yields near optimum performance with complexity comparable to that of the nonblind MMSE receivers.