Chen Liao

Graduation Semester and Year




Document Type


Degree Name

Doctor of Philosophy in Electrical Engineering


Electrical Engineering

First Advisor

Vasant Prabhu


In this dissertation, performance and design of space-time codes have been studied. The main objective of this dissertation has been to improve the performance of space-time codes. This dissertation covers a wide range of topics in space-time codes. It involves theoretical analysis, design, and implementation for space-time trellis codes, space-time turbo codes, and orthogonal space-time codes. We begin with the study of performance analysis of upper bound of pair-wise error probability (PEP) and exact PEP. The exact PEP is derived using a straightforward method. The exact PEP provides a better understanding of the performance behavior to the other range of SNR. Improved design criteria for space-time trellis codes in both slow and fast fading channel using the union bound analysis are proposed. The improved design criteria depend on PEP and distance spectrum analysis. We have applied the criteria in designing codes. The effectiveness of using the distance spectrum as an evaluation tool in evaluating coding gain performance has been demonstrated. With the criteria, optimal codes were searched through coding gain performance in consideration of the distance spectrum. The resulted codes were compared with so-called optimal codes and better performance was obtained. Orthogonal space-time trellis codes have been proposed. The orthogonal space-time trellis codes take advantage of the benefits of the orthogonal design of space-time block codes and maintain the symbol Hamming distance in the meanwhile. The novelty to the approach is that the diversity gain is improved, in comparison to the super-orthogonal space-trellis codes where coding gain is improved. We show that this fundamental difference in properties gives the hopes of achieving remarkable improvement in performance. Turbo-based codes are very promising to significantly improve performance. We proposed a new space-time turbo code, which can reduce the impact of the rank deficient on performance with low design complexity. This is achieved by reducing the number of the rank deficient codeword distance matrix. The proposed codes could achieve significant improvement on FER performance over quasi-static flat fading channel for the small diversity gain.


Electrical and Computer Engineering | Engineering


Degree granted by The University of Texas at Arlington