Vision-Enhanced Communications: On the Benefits of NLOS/LOS Knowledge in Wireless Systems

dc.contributor.authorBrown, Samuel Benjaminen
dc.contributor.committeechairDhillon, Harpreet Singhen
dc.contributor.committeememberHeadley, William C.en
dc.contributor.committeememberBuehrer, Richard M.en
dc.contributor.departmentElectrical Engineeringen
dc.date.accessioned2025-05-31T08:01:55Zen
dc.date.available2025-05-31T08:01:55Zen
dc.date.issued2025-05-30en
dc.description.abstractThe proliferation of Internet of Things (IoT) devices equipped with meteorological, auditory, optical, and infrared sensors has opened the door to integrating sensor-based information into existing physical layer communication system design. Many properties of the wireless channel, especially for mobile applications, are highly dynamic and easily observable using non-radio frequency (RF) sensors or RF sensors operating out-of-band (OOB) which we refer to as vision sensors. Using vision sensors to provide information about one such property, that of line-of-sight (LOS)/non-line-ofsight (NLOS) states, is the central focus of this work. A generalized signal detection framework is presented for a vision sensor-aided receiver operating in a binary continuous-time Markov chain (CTMC) channel environment wherein the NLOS/LOS state toggles intermittently. Several cases are explored wherein varying degrees of NLOS/LOS knowledge are available at the receiver with an emphasis on labeled vs unlabeled information. Bayes risk and composite likelihood ratio test (LRT) methods are used to derive the optimal decision rule in both constant false-alarm rate (CFAR) and minimum probability of error (min(Pe)) paradigms. It is shown that a dynamic detection scheme utilizing labeled information, including imperfect error-prone labels, sourced from vision sensors can improve upon the uniformly-most-powerful (UMP) test in an ensemble of trials, yielding higher CFAR detection rates than static detectors without vision sensors. Further, it is shown that unlabeled information, while matching the CFAR performance of the UMP test, can yield a lower overall error rate compared to a blind receiver with no NLOS/LOS knowledge.en
dc.description.abstractgeneralThe proliferation of Internet of Things (IoT) devices equipped with meteorological, auditory, optical, and infrared sensors has opened the door to integrating sensor-based information into existing wireless communication system design. Many properties of the radio frequency (RF) channel, especially for mobile applications, are highly dynamic and easily observable using sensors operating out-of-band (OOB) such as optical and infrared (IR) cameras and radars operating in different frequency ranges. These vision sensors can provide information about the physical propagation environment beyond what is typically sensed with an existing RF receiver. This work explores the benefits of using vision sensors to determine whether a communication link is line-of-sight (LOS) with a direct path to the transmitter or non-line-of-sight (NLOS) without a direct path. A performance analysis is presented for a receiver with vision information using classical hypothesis testing and detection theory, and a generalized framework is presented to compare performance with perfect vision information and imperfect error-prone information. It is shown that using a dynamic detector, which can adjust its sensitivity based on information about the NLOS/LOS state, can improve its detection performance over a static detector which lacks vision information. This result demonstrates that wireless communications systems can indeed benefit from vision sensors, even if the information they provide is partially corrupted and not always available.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:43944en
dc.identifier.urihttps://hdl.handle.net/10919/134948en
dc.language.isoenen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectSensorsen
dc.subjectInternet of Thingsen
dc.subjectLOS/NLOSen
dc.subjectOut-of-Band Knowledgeen
dc.subjectCFARen
dc.subjectCTMCen
dc.subjectMarkov Channelen
dc.subjectDynamic Channelen
dc.subjectComposite Hypothesis Testingen
dc.titleVision-Enhanced Communications: On the Benefits of NLOS/LOS Knowledge in Wireless Systemsen
dc.typeThesisen
thesis.degree.disciplineElectrical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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