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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.
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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
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
Listener 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.
Comments Concerns when apply to sensor network 2D Constrain Power Consideration Calibration On the Transmitter. Kalman Filter for the Mobile Algorithm