CUHK electronic theses & dissertations collection

Furthermore, we show that geometric retransmission algorithm is intrinsically unstable for large population sizes. On the other hand, exponential backoff algorithm is more robust and scalable. Even for infinity population sizes, the stable throughput and bounded delay region still exists under certain conditions.In the light of the concern, we propose a queueing model of the general CSMA protocol with probability-based backoff scheduling algorithm. The input buffer of each node is modeled as a Geo/G/1 queue, in which the service time distribution of each individual head-of-line (HOL) packet can be described by a Markov chain. By means of this queueing model, we can obtain the characteristic equation of throughput, the packet queueing delay as well as the stable conditions with admissible input traffic. We also specify stable throughput and bounded delay regions with respect to the retransmission factor and input rate.Last but not least, the proposed queueing model can be systematically generalized to investigate various types of MAC protocols, such as ALOHA, CSMA protocols, IEEE 802.11 protocols. Specifically, we illustrate the methodology by full analyses of the non-persistent CSMA and 1-persistent CSMA protocols in this thesis.Medium Access Control (MAC) protocols have been continuously updated to keep up with the emerging new services and QoS requirements. Despite of the rapid changes of MAC protocols, a comprehensive performance analysis of any MAC protocol remains an open issue for over several decades.Most of existing analysis of MAC protocols focused on the network throughput and packet access delay under the assumption that the network is saturated which is not realistic. We know very little about the stability of MAC protocol under the normal network operation for lack of a systematic model that can be adaptively applied to various MAC protocols with different service requirements and backoff scheduling algorithms.Other than the probability-based backoff algorithm, this thesis also includes the study of window-based backoff algorithm. It is shown that the probability-based and window-based backoff algorithms are equivalent to each other. Moreover, we find that the characteristic equation of network throughput is invariant to backoff scheduling algorithms.Wong, Pui King.Adviser: Tony T. Lee.Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: .Thesis (Ph.D.)--Chinese University of Hong Kong, 2011.Includes bibliographical references (leaves 125-133).Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.Abstract also in Chinese