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dc.contributor.authorMullins, Barry E.en_US
dc.description.abstractAn adaptive MAC protocol is developed and analyzed that offers a "best case" scenario by allowing the MAC to control medium parameters thereby fully exploiting the channel of an ad hoc wireless LAN. This new, opportunistic medium access control protocol is called CATER (Code Adapts To Enhance Reliability) and is based on the proposed MAC standard for wireless local area networks (WLAN)-IEEE 802.11 [IEE96]. As currently proposed, IEEE 802.11 uses a fixed pseudo-noise (PN) code for spreading the information signal, implying a fixed process gain at the receiver. When the channel degrades, IEEE 802.11 offers only retransmissions at the MAC layer to combat a corrupt medium. However, CATER allows communicating stations to reconfigure their transceivers to use a longer PN code after a prescribed number of failed retransmissions. This longer code increases the process gain of the receiver and reduces the error rate. After the two stations are reconfigured, the source station sends the frame in question. Immediately after that frame is acknowledged, the source station may send additional frames during the reconfigured period. Simulation and emulation are used to demonstrate and validate the adaptive protocol's capabilities. Results show that this new protocol offers substantial improvement in system throughput when the channel degrades to a point that reliable transmission of frames is not feasible in a standard IEEE 802.11 WLAN. Specifically, CATER continues to function, permitting up to 14 percent normalized aggregate throughput at times when IEEE 802.11 permits no frames to pass through the WLAN. In addition, throughput experiences only a small decrease due to protocol overhead during periods when stations experience a good channel with few bit errors. Moreover, CATER does not adversely affect the predominate transport layer protocol (i.e., TCP), and provides equitable service to all stations within the network.en_US
dc.publisherVirginia Techen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectAdaptive MAC Protocolen_US
dc.subjectIEEE 802.11en_US
dc.subjectSpread Spectrumen_US
dc.titleCater: An Opportunistic Medium Access Control Protocol for Wireless Local Area Networksen_US
dc.contributor.departmentElectrical Engineeringen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
dc.contributor.committeechairDavis, Nathaniel J. IVen_US
dc.contributor.committeememberBostian, Charles W.en_US
dc.contributor.committeememberMidkiff, Scott F.en_US
dc.contributor.committeememberGray, Festus Gailen_US
dc.contributor.committeememberAbrams, Marcen_US

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