A Location-aided Decision Algorithm for Handoff Across Heterogeneous Wireless Overlay Networks

dc.contributor.authorSaleh, Areejen
dc.contributor.committeechairDavis, Nathaniel J. IVen
dc.contributor.committeememberMidkiff, Scott F.en
dc.contributor.committeememberDaSilva, Luiz A.en
dc.contributor.departmentElectrical and Computer Engineeringen
dc.date.accessioned2011-08-06T16:02:42Zen
dc.date.adate2004-08-04en
dc.date.available2011-08-06T16:02:42Zen
dc.date.issued2004-07-19en
dc.date.rdate2004-08-04en
dc.date.sdate2004-07-20en
dc.description.abstractInternetworking third generation (3G) technologies with wireless LAN (WLAN) technologies such as Universal Mobile Telecommunication Systems (UMTS) and IEEE 802.11, respectively, is an emerging trend in the wireless domain. Its development was aimed at increasing the UMTS network'­s capacity and optimizing performance. The increase in the number of wireless users requires an increase in the number of smaller WLAN cells in order to maintain an acceptable level of QoS. Deploying smaller cells in areas of higher mobility (e.g., campuses, subway stations, city blocks, malls, etc.) results in the user only spending a short period of time in each cell, which significantly increases the rate of handoff. If the user does not spend sufficient time in the discovered WLAN's coverage area, the application cannot benefit from the higher data rates. Therefore, the data interruption and performance degradation associated with the handoff cannot be compensated for. This counters the initial objective for integrating heterogeneous technologies, thus only handoffs that are followed by a sufficient visit to the discovered WLAN should be triggered. The conventional RF-based handoff decision method does not have the necessary means for making an accurate decision in the type of environments described above. Therefore, a location-aided handoff decision algorithm was developed to prevent the triggering of handoffs that result from short visits to discovered WLAN's ­ coverage area. The algorithm includes a location-based evaluation that runs on the network side and utilizes a user's location, speed, and direction as well as handoff-delay values to compute the minimum required visit duration and the user'­s trajectory. A WLAN coverage database is queried to determine whether the trajectory's end point falls within the boundaries of the discovered WLAN's coverage area. If so, the mobile node is notified by the UMTS network to trigger the handoff. Otherwise, the location-based evaluation reiterates until the estimated trajectory falls within the boundaries of the discovered WLAN'­s coverage area, or the user exits the coverage area. By taking into consideration more then merely RF-measurements, the proposed algorithm is able to predict whether the user'­s visit to the WLAN will exceed the minimum requirements and make the decision accordingly. This allows the algorithm to prevent the performance degradation and cost associated with unbeneficial/unnecessary handoffs.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.otheretd-07202004-064741en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07202004-064741en
dc.identifier.urihttp://hdl.handle.net/10919/10043en
dc.publisherVirginia Techen
dc.relation.haspartThesis_Saleh_Areej_ETD.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectHeterogeneousen
dc.subjectHandoffen
dc.subject3Gen
dc.subjectIEEE 802.11en
dc.subjectLocation-aideden
dc.subjectUMTSen
dc.subjectWLANen
dc.titleA Location-aided Decision Algorithm for Handoff Across Heterogeneous Wireless Overlay Networksen
dc.typeThesisen
thesis.degree.disciplineElectrical and Computer Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen
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