3.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 .
Use combination of RF and ultrasound to provide a location-support service to users.
Approach
4.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
5.use a relatively sluggish RF data transmission rate.
System Parameters Selection
6.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
7.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.
8.Implementation :Beacon Positioning and Configuration
9.Implementation :Ultrasound Deployment
10.Experiment: Boundary Performance
11.Experiment: Static Performance
12.Experiment: Static Performance (Cont)
13.Experiment: Mobile Performance
14.Comments
Concerns when apply to sensor network
2D Constrain
Power Consideration
Calibration On the Transmitter.
Kalman Filter for the Mobile Algorithm