1、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 lo
2、cation from the set of beacons .,Use combination of RF and ultrasound to provide a location-support service to users.,Approach,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 a
3、nother- System parameters- Listener Inference Algorithms,use a relatively sluggish RF data transmission rate.,System Parameters Selection,Interference Scenarios,RF-A:US-RA Align the beacons RF-A:US-I Using RF signal with long range RF-A:US-RI Ensure less than 5 beacons within range of each other,Lis
4、tener Inference Algorithm,Majority Picks the beacon with highest frequency of occurrence MinMean Selects the beacon with the minimum mean value MinMode 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 network2D ConstrainPower ConsiderationCalibration On the Transmitter.Kalman Filter for the Mobile Algorithm,
