Blind Adaptive Space–Time Multiuser Detection With Multiple Transmitter and Receiver Antennas

The demand for performance and capacity in cellular systems has generated a great deal of interest in the development of advanced signal processing techniques to optimize the use of system resources. In particular, much recent work has been done on space–time processing in which multiple transmit/receive antennas are used in conjunction with coding to exploit spatial diversity. In this paper, we consider space–time multiuser detection using multiple transmit and receive antennas for code-division multiple-access (CDMA) communications. We compare, via analytical bit-error-probability calculations, user capacity, and complexity, two linear receiver structures for different antenna configurations. Motivated by its appearance in a number of thirdgenaeration (3G) wideband CDMA standards, we use the Alamouti space–time block code for two-transmit-antenna configurations. We also develop blind adaptive implementations for the two transmit/two receive antenna case for synchronous CDMA in flatfading channels and for asynchronous CDMA in fading multipath channels. Finally, we present simulation results for the blind adaptive implementations.