Space time transceiver design over multipath fading channels

• Main Author: Zhang, Tingting
• Published: Imperial College London 2008
• Subjects: 621.382
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486374

The objective of the study is to develop novel space-time transceivers for OS-COMA (DirectSequence Code Division Multiple Access) arrayed MIMO (Multiple-Input Multiple-Output) systems operating in multiple-access multipath fading channels. The ever increasing demand for performance and capacity in cellular wireless systems has prompted the development of OS-COMA MIMO systems. Unlike other reported research on MIMO systems which often .assumes the use of multiple antennas, in this thesis, arrayed MIMO system frameworks are proposed, which, by harnessing the geometrical information of the antenna arrays and received signals, provide a richer description of the channel characteristics and additional degrees offreedom in designing communication systems. Firstly, the framework of MIMO arrayed system in a OS-COMA system is developed. Subspace type blind channel estimator and receiver based on Doppler Spatial-Temporal Array (Doppler-STAR) are developed for time varying frequency selective fading channels, providing the system with more accurate channel estimation, higher resolution and superior interference cancellation capabilities. Secondly, joint transmitter and receiver optimisation in multipath and multiple access downlink system is studied. The two dimensional Spatio-Temporal Array manifold matrix (STAR matrix) is introduced. An iterative and a closed-form solution are proposed to solve the optimisation problem of minimising the MSE over the entire network. The proposed schemes offer a performance advantage over transmitter only (Tx-beamforming) and receiver only (Rx-beamforming) beamforming techniques under the system framework. Finally, the framework of an OFOM-CDMA arrayed system is developed. With the aid of Circular Spatial-Temporal ARray (C-STAR) manifold vector, two types of receivers (Le. preFFT and post.;FFT) are proposed-to eliminate the effect of multiple access interference (MAl) and inter-symbol interference (lSI) in a comp,letely blind way.