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Title: Cyclic Prefix-Free MC-CDMA Arrayed MIMO Communication Systems
Author: Peh, Ho Huat
ISNI:       0000 0004 2678 1570
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2009
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The objective of this thesis is to investigate MC-CDMA MIMO systems where the antenna array geometry is taken into consideration. In most MC-CDMA systems, cyclic prefixes, which reduce the spectral efficiency, are used. In order to improve the spectral efficiency, this research study is focused on cyclic prefix-free MC-CDMA MIMO architectures. Initially, space-time wireless channel models are developed by considering the spatio-temporal mechanisms of the radio channel, such as multipath propagation. The spatio-temporal channel models are based on the concept of the array manifold vector, which enables the parametric modelling of the channel. The array manifold vector is extended to the multi-carrier space-time array (MC-STAR) manifold matrix which enables the use of spatio-temporal signal processing techniques. Based on the modelling, a new cyclic prefix-free MC-CDMA arrayed MIMO communication system is proposed and its performance is compared with a representative existing system. Furthermore, a MUSIC-type algorithm is then developed for the estimation of the channel parameters of the received signal. This proposed cyclic prefix-free MC-CDMA arrayed MIMO system is then extended to consider the effects of spatial diffusion in the wireless channel. Spatial diffusion is an important channel impairment which is often ignored and the failure to consider such effects leads to less than satisfactory performance. A subspace-based approach is proposed for the estimation of the channel parameters and spatial spread and reception of the desired signal. Finally, the problem of joint optimization of the transmit and receive beam-forming weights in the downlink of a cyclic prefix-free MC-CDMA arrayed MIMO communication system is investigated. A subcarrier-cooperative approach is used for the transmit beam forming so that there is greater flexibility in the allocation of channel symbols. The resulting optimization problem, with a per-antenna transmit power constraint, is solved by the Lagrange multiplier method and an iterative algorithm is proposed.
Supervisor: Manikas, Athanassios ; Constantinides, Anthony ; Wong, Wai-Choong ; Tjhung, Tjeng Thiang Sponsor: Agency for Science, Technology and Research
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral