Abstract:
The application of information theory and digital signal processing techniques to digital
communication has resulted in robust methods for reliable high speed data transmission
over noisy channels environments. Among these methods, multicarrier systems have
become a viable solution for exploiting maximum spectral efficiency over both wideband
highly dispersive static and time-varying dynamic channels. However, there remains many
problems in this field to maximize performance and efficiency of such systems. Among
these problems, equalization and synchronization are the major focus of this thesis.
The contribution of this thesis on equalization is to optimize performance of equalizer
from two different aspects: computational complexity and system capacity. A new
fast equalization algorithm is developed to obtain near optimum setting of the equalizer
under minimum mean square error criterion. Furthermore, a mathematical framework for
analysis of maximum capacity equalization is developed. It is shown that the optimum
equalization of multi-carrier system can be viewed as a constrained optimization problem
where the constraint set exhibits identifiable geometric characteristic. Using these properties,
a descent gradient search method for optimum equalization of multi-carrier systems
is proposed.
In synchronization domain, the contribution of this thesis is the development and
statistical analysis of a new class of cyclic based estimators: maximum likelihood and
minimum variance unbiased and moment estimator for both symbol timing error and
carrier frequency offset estimation of multicarrier systems.
