Hot Topics in Mobile and Pervasive Computing 2

Hot Topics in Mobile and Pervasive Computing 2

اسلاید 1: 1CSCE 5013: Hot Topics in Mobile and Pervasive ComputingNilanjan BanerjeeHot Topic in Mobile and Pervasive ComputingUniversity of ArkansasFayetteville, ARnilanjan.banerjee@gmail.com

اسلاید 2: 2What is localization, aka location?absolute location (lat, long)relative locationcontext location

اسلاید 3: 3Why should I care about localization? social applicationadvertisementspodcasting

اسلاید 4: 4What can I use to localize my phone?GPSCell towerWi-FiBluetoothRFIDSoundAmbience

اسلاید 5: 5How does these technologies work (Centroid scheme)abcWi-Fi B.S #1Wi-Fi B.S #2Wi-Fi B.S #3Youdistance from BSs position of the BSs

اسلاید 6: 6Position of the BSsFind position of the APs and cell towersBased on databases already available (Placelab Intel Research)Cell phone companies know the position of their cell towers

اسلاید 7: 7Distance measuresReceived Signal Strength Indication (RSSI)Correlation between RSSI and distanceTime to propagationAmount of time for signal to propagate from source to destinationDistance = time * speed of propagation

اسلاید 8: 8Alternate method purely based on profiling…Take extensive measurements of your environmentWar driving Similar to what Jonathan and Warner are doingCollect tuples <location, <AP1, signal strength> , <AP2, signal strength>, ….>Scan and look for APs or cell towersMatch with your measurementsCompare with the signal strength and set of APs in the scan and your measurements Choose location which matches closely to the collected measurements

اسلاید 9: 9Relative positioning of individualsBluetooth/Wi-Fi/sound/InfraredPlacing people in a two dimensional planeApplication to localization in ad hoc networks

اسلاید 10: 10Trade-offs between some of these schemes…Energy hungryVery accurateWorks outdoorsEnergy hungryModerately accurateWorks outdoor and indoorNo Energy costVery inaccurateWorks outdoor and indoorlow energy accurate very short range

اسلاید 11: 11Challenges…High Accuracy of localizationEnergy-EfficiencyDistance measure RSSI?Location Privacy

اسلاید 12: 12Papers we will cover under localizationSurroundSense: Mobile Phone Localization via Ambience Fingerprinting BeepBeep: A High Accuracy Acoustic Ranging System using COTS Mobile Devices    Sherlock: Automatically locating objects for human  Ambient sources RFIDSound

اسلاید 13: 13Next classReviews due for the following paperSurroundSense paperReview due by 11:59 p.m. tomorrow Extra class on iptables tomorrow in 239 from 3:30-4:30