- Slides: 14
The Cricket Location-Support System By: Min Chen 10/28/03
Goal User Privacy Decentralized administration Network heterogeneity Low cost Room-sized granularity
System Architecture Beacon: Disseminate the string of space information about a geographic space to listeners. Listener: Infer its current location from the set of beacons. Approach Use combination of RF and ultrasound to provide a location-support service to users.
Related Problem and Method Collision of RF transmissions from different beacons ------Randomization Wrong correlation of the RF data of one beacon with the ultrasonic signal of another ------ System parameters ------ Listener Inference Algorithms
System Parameters Selection use a relatively sluggish RF data transmission rate.
Interference Scenarios RF-A: US-RA n Align the beacons RF-A: US-I n Using RF signal with long range RF-A: US-RI n Ensure less than 5 beacons within range of each other
Listener Inference Algorithm Majority n Picks the beacon with highest frequency of occurrence Min. Mean n Selects the beacon with the minimum mean value Min. Mode n Compute the per-beacon statistical mode over the past n samples.
Implementation : Beacon Positioning and Configuration
Implementation : Ultrasound Deployment
Experiment: Boundary Performance
Experiment: Static Performance
Experiment: Static Performance (Cont)
Experiment: Mobile Performance
Comments Concerns when apply to sensor network 2 D Constrain Power Consideration Calibration On the Transmitter. Kalman Filter for the Mobile Algorithm