Thesis (M.A.)--Indiana University, 2007. / Title from screen (viewed on June 27, 2007) Department of Communication Studies, Indiana University-Purdue University Indianapolis (IUPUI) Includes vita. Includes bibliographical references (leaves 160-167)

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

This paper architecturally describes the switching portion of a digital communications system that is dedicated to conferencing. The basic ideas and methods of circuit switching and packet switching are introduced. The conferencing function is described, and some resulting design considerations are discussed. The architecture of the switch is then presented. Circuit switching techniques are used throughout the architecture of the switch, coupled with arithmetic processing to accomplish the conferencing function. The architecture is developed in such a way that it is expandable in all directions to meet a given set of requirements. The requirements include the number of users the system supports and the number of conference channels provided. The processing stages of the switch can be sized based on these requirements and the chosen component speeds. The basic timing of each stage is given to describe its operation and establish the critical delay paths. The resulting switching methods first introduced. The switch is also tested to see if it fits the criteria for being a distributed processing system. It is concluded that if the provision for dynamic reconfiguration is added, the switch fits the criteria. Finally, further topics of study are suggested.

Universal service is the focal point of the economic dilemma faced by the telecommunications industry. The advent of competition spurred by several regulatory rulings is forcing rates towards economic costs. It is feared that this movement or the erosion of the toll-to-local subsidy with concomitant increases in local prices severely threatens the concept of universal service. To adequately address these fears, accurate elasticity of demand estimates for telephone access are required. This thesis develops estimates of these demand elasticities for access. These estimates are derived consistently from an underlying theory of demand for access. Furthermore, the simultaneous access and class-of-service choice problems are addressed similarly. This consistent development facilitates model usage and interpretation. For example, the model provides the best available estimate for the size of the network externality. Taking into account the underlying demand theory and acknowledging the problems associated with the aggregated nature of the data set (census tract data from 1980 Census), a modified probit technique is developed to estimate the demand model. The estimation methodology is implemented using an iterative least square procedure. To analyze the reasonableness of the algorithm and procedure, a Monte Carlo study is performed. In addition, a jackknife technique is employed to estimate variances of coefficients when the standard measures are unavailable. The model results are used to analyze the effect of current policy decisions. For example, for a proposed doubling of access prices the demand for access elasticity is found to be quite small, about -.04. A welfare analysis is performed to discuss the costs and benefits associated with moving to cost-based rates. This analysis also provides the basis for rate recommendations to facilitate the transition to competition while attempting to preserve the concept of universal service.

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 (Ph. D.)--University of Hong Kong, 1992. / Also available in print.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xiii, 274 p.; also includes graphics (some col). Includes abstract and vita. Advisor: Douglas N. Jones, Dept. of Public Policy and Management. Includes bibliographical references (p. 275-317).

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