The application of subspace technologies in wireless communication systems.

摘要

Multiuser signal detection and estimation are key techniques for overcoming band-width limitations and combating MAI in wireless systems. In many practical situations, it is difficult for the receiver to know the information of any user other than the desired user at mobile stations. On the other hand, there are also considerable discussions about multiuser transmitter design at base stations to simplify the corresponding multiuser receiver design without sacrificing system performance.; Several new joint multiuser DOA/FOA blind estimators based on LS and TLS estimations are presented. These new joint DOA/FOA blind estimators are based on a space-time data model by extending the classic MUSIC and ESPRIT algorithm structure. Several improvement schemes are also proposed.; Concerning MUD, several one-shot semi-blind/blind detectors with LS estimation, TLS estimation and mixed LS and TLS estimation are presented for synchronous and asynchronous wireless communication systems. These detectors are based on a new semi-blind/blind signature matrix and can detect several consecutive bits at the same time using extended multiple truncated-windows and are expected to provide a better performance in asynchronous CDMA systems.; Interference cancellation is a MUD method for suppressing the effects from MAI and consequently improving the system performance. We introduce several soft interference cancellation schemes, including individually and jointly optimum interference cancellation, direct interference cancellation, MAME interference cancellation and MMSE interference cancellation algorithms.; In addition to multiuser receiver design methodologies, the structure and principles of multiuser transmitter design are reviewed in this dissertation. In addition to multiuser precoding using MMSE criterion, optimum multiuser precoding schemes, individually optimum precoding and jointly optimum precoding, and linear multiuser precoding schemes, decorrelating precoder, AML precoder and MAME precoder, are presented to mitigate MAI in synchronous CDMA systems.; Theoretical analysis and computer simulations will be presented to support the performance of the proposed algorithms.