abstract / Computer Science / Doctoral / Doctor of Philosophy

With fast and prosperous development in communication technology, desktop or mobile devices may be equipped with wired and wireless network interfaces. Hence, users need a multihoming technique to help them making use of the network in- terfaces effectively. The Stream Control Transmission Protocol (SCTP) is a new transport protocol approved by the SIGTRAN Working Group of IETF (Internet Engineering Task Force) as RFC 2960 in October 2000 where it includes this useful characteristic. However, this feature may lead to some secure pitfalls. In this thesis, we come up with some approaches to improve SCTP against some existing tough problems raised from multihoming and provide more sufficient protection methods based on cryptography. Finally, a comparison of the existing security solutions is also given to demonstrate our contributions.

Licentiatavhandling Karlstad : Karlstads universitet, 2008.

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Paul D. Amer, Dept. of Computer & Information Sciences Includes bibliographical references.

Several efficient low complexity interference management techniques were developed for improving the performance of multiple-input multiple-output (MIMO) networks. Sub-optimal techniques involving optimal antenna selection-aided stream control were proposed for joint optimization of co-channel MIMO links in a space division multiple access (SDMA) network. Results indicated that the use of the SDMA scheme along with partial channel state information at the transmitters significantly reduces the signaling overhead with minimal loss in throughput performance. Next, a mean squared error (MSE) based antenna selection framework was presented for developing low complexity algorithms for finite complexity receivers. These selection algorithms were shown to provide reasonable bit-error rate performance while keeping the overall system complexity low. Furthermore, some new algebraic properties of linear orthogonal space-time block codes (OSTBCs) were utilized to develop a single-stage and minimum MSE optimal detector for two co-channel users employing unity rate real and derived rate-1/2 complex OSTBCs. A sub-optimal space-time interference cancellation (IC) technique was also developed for a spatial-multiplexing link subjected to Alamouti interference. The performance of proposed interference management techniques and their implications for future research are discussed.

Thesis (M. Sc.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (p. 105-108). Also available via the World Wide Web.

Thesis (M.S.)--University of Delaware, 2005. / Principal faculty adviser: Paul D. Amer, Dept. of Computer & Information Sciences. Includes bibliographical references.

Thesis (M.E.)--University of Canterbury, 2006. / Typescript (photocopy). "December 2006." Includes bibliographical references (p. 83-86). Also available via the World Wide Web.

La presente tesina consiste en el diseño de migración de nodos B aplicado para una RNC caída de una red móvil, con la finalidad de solucionar los problemas que se presenten ante un incidente que afecte los servicios de voz y datos de los usurarios de una red móvil. En el desarrollo de la tesina, se describe el planteamiento del problema, el marco teórico de la tecnología UMTS y posteriormente nos centramos en los elementos principales de esta tecnología. También describimos los equipos importantes a utilizar en desarrollo del proyecto, en este caso nos enfocamos en la descripción de la RNC. Y finalmente describimos el desarrollo del proyecto, el diseño de la solución e implementación de la misma, y en donde se presentan los resultados del diseño. This thesis is the design of migration of nodes B and its a applied when RNC fall for a mobile network, in order to solve the problems that arise before an incident affecting voice and data services from a mobile network. In developing the thesis, we describe the theoretical framework of UMTS technology and then we focus on the main elements of this technology. We also describe the important equipment used in project development; in this case we focus on the description of the RNC. And finally we describe the solution of design and implementation .Also, the results of this project.