Browsing by Author "Chakraborty, Sandip"

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    Capacity Enhancement, QoS and Rate Adaptation in IEEE 802.11s: A Performance Improvement Perspective
    (2014) Chakraborty, Sandip
    Current deployment of wireless community and municipal area networks provide ubiquitous connectivity to end users through wireless mesh backbone, that aims at replacing wired infrastructure through wireless multi-hop connectivity. IEEE 802.11s standard is published recently to support the mesh connectivity over well-deployed IEEE 802.11 architecture based on Wireless Fidelity (WiFi) access network. This thesis explores a number of research directions to optimize the mesh peering, channel access, scheduling and mesh path selection protocols for IEEE 802.11s mesh network. The standard provides three major protocols to support mesh functionality - Mesh Peer Management Protocol (MPM) to establish mesh connectivity and for topology management, Mesh Coordinated Channel Access (MCCA) for channel access and scheduling, and Hybrid Wireless Mesh Protocol (HWMP) to support mesh path establishment based on link layer characteristics. The objective of this thesis is to augment the existing protocols for better connectivity and e cient usage of the resources. In a mesh network, the e ciency of the backbone network can be improved through directional communication by exploring spatial reuse capability. However, uses of directional antennas impose several new research challenges that are explored in this thesis. The rst contribution of this thesis enhances the functionality of the mesh channel access and path selection protocols to support directional communication over an IEEE 802.11s mesh backbone. Though MCCA provides reservation based channel access, the standard does not implement any speci c mechanism for multi-class tra c services to improve the Quality of Service (QoS) for the end-users. The next contribution in this direction is to provide QoS support and service di erentiation for MCCA based channel access mechanism over the multi-interface communication paradigm. Modern wireless hardwares are capable of providing multiple data rate supports depending on wireless channel dynamics. As a consequence, the MPM protocol has been augmented to support multi-rate adaptation over IEEE 802.11s protocol elements.