الفهرس 
Wireless and Mobile Communication SystemsOnly 14 pages are availabe for public view
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Abstract
Multimedia applications such as video-conferencing, telemedicine, etc. have very stringent quality-of-service (QoS) demands and require a connection-oriented service. For these applications, a path satisfying their requirements in terms of bandwidth, delay, buffer, etc. needs to be found. The upcoming gigabit-per-second high-speed networks are expected to support a wide range of communication-intensive real-time multimedia applications. The requirement for timely delivery of digitized audio-visual information raises new challenges for next generation integrated services broadband networks. One of the key issues is QoS routing. It selects network routes with sufficient resources for the requested QoS parameters.
By concerning QoS routing, two major challenges might be existed:
• The optimum routing problem with multiple independent QoS constraints is mostly NP-hard.
• Imprecise QoS information may make routing decision obsolete.
Practically, the QoS routing algorithms have to take these challenges above into consideration. Probing is an effective method to deal with the NP-hardness and the imprecise routing information problem. Probing firstly proposed by Chen and Nahrstedt [CN98b] in their Ticket-based routing (TBR) algorithm.
According to the work in this thesis, an Enhanced Ticket-Based Probing routing (ETBP) algorithm has been proposed to improve the searching ability of tickets by distributing the tickets in different manner to increase the success ratio and decrease the delay such that better paths can be found. Also an enhancement added to the flooding algorithm to improve its performance. Both of these two algorithms are studied from the point of view of delay.
The thesis is divided into six chapters. Chapter 1, survey of wireless networks, categories of the wireless networks and the current wireless systems will be introduced. In chapter 2, overview of the Quality of Service (QoS) routing and the best-effort routing, the difference between them, the importance of QoS routing in the field of networking, their applications and the challenges of QoS and solutions will be introduced. In chapter 3, the routing algorithms in wireless their problems, categories, strategies will be illustrated. In chapter 4, an explanation of the Ticket-Based Probing Algorithms, limitations of Ticket-Based Probing Algorithms and how to overcome these limitations. Also, Enhanced Ticket-Based Probing Algorithms will be introduced including a comparison between them and the original TBP and mixed algorithm. In chapter 5, an enhancement to the flooding algorithm is done and a comparison between it and the original one is made to illustrate its performance. Last, in chapter 6, a final conclusion will be done and also proposed future work will be given.