BEACON ARRAY

• US 20160381582A1
• Filed: 11/25/2015
• Published: 12/29/2016
• Est. Priority Date: 06/24/2015
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Li, YuBo, Lin, Yonghua, Wang, Qing, Wang, Wei Dong, Xue, Chao
• Granted Patent: US 9,746,541 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 1/00 Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith position fixing by co-ordinating a plurality of determinations of direction or position lines G01S5/00
• CPC Class Codes: G01S 1/024 of beacon transmitters
• CPC Class Codes: G01S 11/06 using intensity measurements

Abstract

A method comprises receiving a first received signal strength indicator (RSSI) of a first beacon in an array of beacons and receiving a second RSSI of a second beacon in an array of beacons, calculating a RSSI of the array (r) as a function of the first RSSI and the second RSSI, retrieving a calibrated RSSI value of the array (r′) from a memory, determining whether r>r′, and outputting a signal to a user device responsive to determining that r>r′.

Claims

1. A method comprising:

receiving a first received signal strength indicator (RSSI) of a first beacon in an array of beacons and receiving a second RSSI of a second beacon in an array of beacons;

calculating a RSSI of the array (r) as a function of the first RSSI and the second RSSI;

retrieving a calibrated RSSI value of the array (r′

) from a memory;

determining whether r>

r′

; and

outputting a signal to a user device responsive to determining that r>

r′

.

2. The method of claim 1, wherein the signal output to the user device is associated with the array of beacons.

3. The method of claim 1, wherein the array of beacons partially defines a hotspot such that when r>

r′

the user device is located in the hotspot.

4. The method of claim 1, wherein the RSSI of the array is defined by

5. The method of claim 4, wherein the coherence time window of the beacons in the beacon array is modeled as a partition of a sequence (x1, x2, . . . xn) and a criterion of the sequence minimizes a sum of the standard deviation of each partition, where T=Partition(X,Q,F), X is an input sequence, Q is a utility function of the partition, F is a boundary condition, and T is the output in a sequence of thresholds, wherein if F is satisfied, Ø

is returned, maximizing Q, X is partitioned into Xl and Xr with a threshold T, Tl=Partition(Xl, Q, F) and Tr=Partition(Xr, Q, F), which returns Tl∪

{t}∪

Tr. Q=std(x)−

sum{(xi/x)*std(xi)}, and a maximal distance between the threshold Tl and Tr is the coherence time.

6. The method of claim 1, wherein the first beacon is operative to output a signal having a transmission interval and the transmission interval is adjustable.

7. The method of claim 1, wherein the calibrated RSSI value of the array is defined by