Thesis (Ph.D.)--University of Alberta, 2009. / Title from PDF file main screen (viewed on Sept. 8, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Department of Electrical and Computer Engineering, University of Alberta." Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Supervisor: Gustavo de Veciana. Vita. Includes bibliographical references.

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The performance of space-time block codes in providing transmit diversity is severely degraded when strong localized interference is present. This problem is addressed by investigating a recently proposed coherent space-time block code decoding algorithm for unknown interference suppression. The algorithm assumes a Gaussian noise and interference approximation and is based on a cyclic-based maximum-likelihood estimation technique (CML). In this thesis, simulations are done applying CML in a coherent system with unstructured interference to validate previous work. An extension of these results is obtained by examining factors that affect CML performance and modifying CML for use in a noncoherent system. To improve bit error rate performance, a turbo code for channel coding was added to both systems. This addition required the development of reliability metrics for soft-information transfer between the space-time block code detector and the turbo code decoder. Significant coding gains exceeding 8dB at a bit error rate of are achieved for the turbo-coded system when compared to that of an uncoded system.

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A mobile ad hoc network (MANET) is a collection of mobile nodes that form a wireless network without the use of a fixed infrastructure or centralized administration, and every node acts as a host as well as a router. The topology of an ad hoc network changes frequently and unpredictably. The mobile nature and dynamic topology of MANETs make it very difficult to provide Quality-of-Service (QoS) assurance in such networks. Considering the limited bandwidth and battery power, finding routes that satisfy the bandwidth constraint of applications is a significant challenge. Ad hoc on-demand distance vector routing (AODV) is an on-demand routing protocol that only provides best-effort routes. QS-AODV is proposed in this thesis. It is based on AODV and creates routes according to the QoS requirements of the applications. It is shown that QS-AODV provides performance comparable to AODV under light traffic. In heavy traffic, QS-AODV provides higher packet delivery ratios and lower routing overheads, at a cost of slightly longer end-to-end delays as the routes in QS-AODV are not always the shortest. The effects of network size and mobility on the performance of QSAODV are shown.

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