Enhanced link layer handover based on localization

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dc.contributor.advisorVentura, Necoen_ZA
dc.contributor.authorKumbuza, Xolaen_ZA
dc.date.accessioned2014-07-31T10:55:17Z
dc.date.available2014-07-31T10:55:17Z
dc.date.issued2008en_ZA
dc.descriptionIncludes abstract.
dc.descriptionIncludes bibliographical references (leaves 60-63).
dc.description.abstractWireless Technologies over the past years have become cheaper and more available to users. In the Infrastructure Mode of operation, when a mobile node moves from the coverage of one Access Point (AP) to the coverage of another AP, it is said to undergo handoffs. The mobile node has to complete a link layer handoffs together with other tasks associated with handoffs in order to effectively have a new wireless link with the new AP. The link layer handoffs currently specified and practiced in IEEE 802.11 is normally carried out in three time steps. These are; the Scanning Phase; the Authentication Phase and the Association Phase. During the three steps the mobile node is unable to send or receive data meaning that packets are lost or delayed causing real-time applications such as video streaming or VoIP, which can only tolerate an end-to-end delay of 50 ms during handoffs, to suffer. The Scanning phase can be done passively or actively. In passive scanning, the mobile node listens on every bandwidth channel for Beacon Frames from the APs. In active scanning, the mobile node sends Probe Requests frames on every channel expecting to receive Probe Responses from the APs operating on each channel. Localization is the process of a node ending its position in space. Localization methods include the Global Positioning Service (GPS), Cricket, Ultrasonic Location and many more. This study investigates how localization can be used to decrease the latency delay experienced at the link layer during wireless handoffs. In our method, a mobile node is given the ability to have knowledge of the APs through an AP-Table server. The mobile node then uses localization to and the closest APs to it and make faster, smarter handoffs. Our simulations are implemented using the NCTUns network simulator and emulator. The simulations comprise of a mobile node undergoing handoffs between APs in the same subnet and APs in different subnets. Added to that, the direction of the mobile node is monitored and used to further assist the handoffs process to alleviate the number of total handoffs. Our research shows the disadvantages and advantages of the proposed system as it integrates localization and direction into WLAN and mobile communication.en_ZA
dc.identifier.apacitationKumbuza, X. (2008). <i>Enhanced link layer handover based on localization</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering. Retrieved from http://hdl.handle.net/11427/5189en_ZA
dc.identifier.chicagocitationKumbuza, Xola. <i>"Enhanced link layer handover based on localization."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 2008. http://hdl.handle.net/11427/5189en_ZA
dc.identifier.citationKumbuza, X. 2008. Enhanced link layer handover based on localization. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Kumbuza, Xola AB - Wireless Technologies over the past years have become cheaper and more available to users. In the Infrastructure Mode of operation, when a mobile node moves from the coverage of one Access Point (AP) to the coverage of another AP, it is said to undergo handoffs. The mobile node has to complete a link layer handoffs together with other tasks associated with handoffs in order to effectively have a new wireless link with the new AP. The link layer handoffs currently specified and practiced in IEEE 802.11 is normally carried out in three time steps. These are; the Scanning Phase; the Authentication Phase and the Association Phase. During the three steps the mobile node is unable to send or receive data meaning that packets are lost or delayed causing real-time applications such as video streaming or VoIP, which can only tolerate an end-to-end delay of 50 ms during handoffs, to suffer. The Scanning phase can be done passively or actively. In passive scanning, the mobile node listens on every bandwidth channel for Beacon Frames from the APs. In active scanning, the mobile node sends Probe Requests frames on every channel expecting to receive Probe Responses from the APs operating on each channel. Localization is the process of a node ending its position in space. Localization methods include the Global Positioning Service (GPS), Cricket, Ultrasonic Location and many more. This study investigates how localization can be used to decrease the latency delay experienced at the link layer during wireless handoffs. In our method, a mobile node is given the ability to have knowledge of the APs through an AP-Table server. The mobile node then uses localization to and the closest APs to it and make faster, smarter handoffs. Our simulations are implemented using the NCTUns network simulator and emulator. The simulations comprise of a mobile node undergoing handoffs between APs in the same subnet and APs in different subnets. Added to that, the direction of the mobile node is monitored and used to further assist the handoffs process to alleviate the number of total handoffs. Our research shows the disadvantages and advantages of the proposed system as it integrates localization and direction into WLAN and mobile communication. DA - 2008 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2008 T1 - Enhanced link layer handover based on localization TI - Enhanced link layer handover based on localization UR - http://hdl.handle.net/11427/5189 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/5189
dc.identifier.vancouvercitationKumbuza X. Enhanced link layer handover based on localization. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Electrical Engineering, 2008 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/5189en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Electrical Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherElectrical Engineeringen_ZA
dc.titleEnhanced link layer handover based on localizationen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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