Please use this identifier to cite or link to this item: http://jadunivdspace.jdvu.ac.in/handle/123456789/20186
Title: Adaptive Call Admission Control Mechanisms for QoS Provisioning in WiMAX Networks
Authors: Saha Misra, Iti
Laishram, Romesh
Keywords: Electronics & Telecommunication Engineering
Issue Date: 2010
Abstract: Emergence of different wireless technologies in recent past has projected wireless as an alternate medium for internet connectivity. Wireless technologies are able to provide mobility and portability that makes it more attractive as compared to wired technologies. Further, increasing requirement to support ubiquitous connectivity with higher data rate for mobile computers and communication devices are fuelling a growing interest in broadband wireless access (BWA) networks. To solve issues related to BWA and frame specifications for it, study group 802.16 was formed under IEEE project 802 to recommend an international standard for Wireless Metropolitan Area Networks (Wireless MAN). Quality of Service (QoS) is one of the added values for IEEE 802.16 standard over other existing wireless standards. WiMAX is defined as Worldwide Interoperability for Microwave Access by the WiMAX Forum, an industrial body formed in June 2001 to promote conformance and interoperability of the IEEE 802.16 standard. The Forum describes WiMAX as a standards-based technology enabling the delivery of wireless broadband as an alternative to cable and DSL. It is being seen as a tool to bridge the Digital Divide by providing applications over the air to sparsely populated regions across the world. Although IEEE 802.16 standard defined the QoS parameters, they do not specify how these QoS parameters are satisfied and it is an open issue for research. This thesis analyses the design of Call Admission Control (CAC) scheme for QoS provisioning in IEEE 802.16 based WiMAX networks. First a bandwidth efficient CAC scheme is propose with bandwidth and delay guarantee that generally operates at the (Medium Access Control) MAC layer. The concept of adaptive bandwidth degradation is introduced to improve the bandwidth utilization of the system. A Markov Chain based analytical model is developed to evaluate the performance of the CAC scheme. The proposed CAC scheme is compared with an existing CAC scheme that uses the concept of fixed step size degradation. Second an adaptive guard channel based CAC scheme is propose considering the Adaptive Modulation and Coding (AMC) that basically operates at the (Physical) PHY layer. With AMC, the modulation type of a user’s connection can be changed dynamically due to worsening of the channel and the ongoing connection might fail due to the change of modulation. Adaptive modulation is a powerful technique to improve the spectral efficiency in wireless transmission over fading channels. Similarly, it is possible to apply the adaptive modulation technique to CAC scheme in order to enhance network performance satisfying QoS requirements.
Description: Full Text
URI: http://dspace.jdvu.ac.in/handle/123456789/20186
Appears in Collections:Electronics & Telecommunication Engineering - Master's Degree Theses

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