Thesis (M.A.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004. / Includes bibliographical references (leaves 80-81). Also available in electronic version. Access restricted to campus users.

Thesis (M.A.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains vii, 85 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 74-81).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 80-82). Also available via the Internet.

This thesis reports on an investigation into the teletraffic modelling and performance of layered cellular networks that use overflow for new call and handover attempts in order to improve system performance It addresses the important problems how to model and analyse overflow in large cellular networks so that the overall impact across the network can be evaluated, the overflow policies that can be used with new calls and handovers to improve network performance and how these policies perform under a range of conditions. The general problem of modelling overflow in cellular networks is considered at length and from this it is concluded that the use of overflow in existing schemes such as directed retry, reuse partitioning and overlaid cells can also be described by the simple concepts of intra and inter layer overflow Using these concepts the author formulates the problem of overflow in layered networks as a subset of the general problem of overflow with multiple overflow routes and restricted overflow. This leads to the derivation of the mean and variance of the overflow traffic from a cell with multiple handover routes and restricted handover from the two-dimensional birth death model of the system. These expressions for the mean and variance are used in conjunction with the Equivalent Random Theory and splitting formulae in the development of the Splitting Formula Method or SF Method. The accuracy of three splitting formulae and a simple Poisson approximation are investigated and compared with simulation. From this we conclude that the splitting formulae of Akimaru and Takahashi and Wallstrom provide the best overall result. This method is used to solve the general problem of multiple user classes for an example two layer network. This leads to conclusions on the complex relationship between cell capacity, the proportion of uses that can access the microcells and the proportion of users that can overflow from the microcell to the macrocell. The Modified Splitting Formula Method is an extension of the SF Method that includes handovers and overflow for handovers. A user perceived measure of the effect of new call and handover blocking described by the probability of call failure augments the Modified SF method. This is then used to analyse five new call overflow policies for a three layer network under conditions of extended handover, restrictions on handover for calls in cells at the edge of layers and spatial offset between the peak of the traffic demand and the cell layout. The results give new and valuable insight into the behaviour of layered cellular networks with overflow and the trade-offs in performance that exist when designing and operating these networks.

Thesis (M.A.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains v, 45 p. : ill. (some col.), maps. Vita. Includes abstract. Includes bibliographical references (p. 41-42).

published_or_final_version / Business / Doctoral / Doctor of Philosophy

Telecommunication has experienced significant changes over the past few years and its paradigm has moved from wired to wireless communications. The wireless channel constitutes the basic physical link between the transmitter and the receiver antennas. Therefore, complete knowledge of the wireless channel and radio propagation environment is necessary in order to design efficient wireless communication systems. This PhD thesis is devoted to studying the spatial and temporal statistics of the wireless channel in cellular environments based on a geometry-based stochastic physical channel modeling approach. Contributions in this thesis report include the following: ??? A new physical channel model called the eccentro-scattering model is proposed to study the spatial and temporal statistics of the multipath signals in cellular environments. ??? Generic closed-form formulas for the probability density function (pdf) of angle of arrival (AoA) and time of arrival (ToA) of the multipath signals in each cellular environment are derived. These formulas can be helpful for the design and evaluation of modern communication systems. ??? A new Gaussian scattering model is proposed, which consists of two Gaussian functions for the distribution of scatterers around base station (BS) and mobile station (MS) and confines these scatterers within a scattering disc. ??? The effect of mobile motion on the spatial and temporal statistics of the multipath signals in cellular environments is discussed. Three motion scenarios are considered for the possible trajectory of the mobile unit. Furthermore, two different cases are identified when the terrain and clutter of mobile surrounding have additional effect on the temporal spread of the multipath signals during motion. ??? The physical channel model is employed to assess the performance of a RAKE receiver in cellular environments. ??? Comparisons between uniform scattering and Gaussian scattering, which are the two assumptions for the distribution of scatterers usually used in the derivation of the pdf of AoA, are also presented. ??? An overview of earlier physical channel models and comparisons between these models and with the proposed model are presented.

This paper describes the successful implementation of a prototype software application that independently and proactively detects whether a mobile phone is lost or misused. When the mobile phone is detected as being lost or misused, the application takes steps to mitigate the impact of loss and to gather evidence. The goal is to aid in the recovery of the mobile phone. The prototype works regardless of the cellular infrastructure the mobile phone is operating in and makes minimum demands on the owner of the mobile phone. The prototype was developed on Nokia 6600 mobile phones that run Symbian Operating System 7.0s. Development was done using Nokia’s Series 60 Developer’s Platform 2.0. / Singapore-MIT Alliance (SMA)

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): R. Clark Robertson, Tri T. Ha. Includes bibliographical references (p. 83-84). Also available online.