Wireless local area network (WLAN) method and system for presence detection and location finding
DC
First Claim
Patent Images
1. A presence detection system incorporated within a wireless local area network (WLAN), comprising:
- one or more WLAN access points each including a received signal strength measurement circuit and operating according to a revision of the IEEE 802.11 specification;
an asset transmitter for transmitting a broadcast/multicast presence signal, wherein said presence signal is transmitted on one or more channels of said WLAN, to which no receiving unit in the WLAN can make a response and for which no association with another unit of said WLAN is required, and wherein said asset transmitter comprises a sniffer circuit for detecting other WLAN transmissions and wherein said asset transmitter transmits said presence signal only when said sniffer circuit detects that said other transmissions are absent; and
an evaluator coupled to said one or more WLAN nodes for receiving signal strength values from each received signal strength measurement circuit within said one or more WLAN nodes and determining whether or not said asset transmitter is present in the vicinity of said one or more WLAN nodes in conformity with said signal strength values, whereby said presence signals can be detected by said access points without association of said asset transmitter with said WLAN while maintaining normal operation with other associated units of said WLAN.
8 Assignments
Litigations
0 Petitions
Accused Products
Abstract
A wireless local area network (WLAN) method and system for presence detection provide a low-cost and WLAN-compatible means for detecting the presence of an asset without requiring full location-finding support within a WLAN environment. The presence of a transmitter is detected by examining the signal strength of a presence signal. The presence signal is WLAN-compatible, but does not require association of the transmitter with the WLAN and does not require a response from the WLAN. The presence signal may be transmitted on multiple WLAN channels for presence detection by multiple WLAN APs. The presence signals transmissions may be periodic or may be stimulated by a stimulus from the WLAN or external device that may or may not be coupled to the WLAN. Location finding can also be performed in combination with the signal strength presence detection.
74 Citations
20 Claims
-
1. A presence detection system incorporated within a wireless local area network (WLAN), comprising:
-
one or more WLAN access points each including a received signal strength measurement circuit and operating according to a revision of the IEEE 802.11 specification; an asset transmitter for transmitting a broadcast/multicast presence signal, wherein said presence signal is transmitted on one or more channels of said WLAN, to which no receiving unit in the WLAN can make a response and for which no association with another unit of said WLAN is required, and wherein said asset transmitter comprises a sniffer circuit for detecting other WLAN transmissions and wherein said asset transmitter transmits said presence signal only when said sniffer circuit detects that said other transmissions are absent; and an evaluator coupled to said one or more WLAN nodes for receiving signal strength values from each received signal strength measurement circuit within said one or more WLAN nodes and determining whether or not said asset transmitter is present in the vicinity of said one or more WLAN nodes in conformity with said signal strength values, whereby said presence signals can be detected by said access points without association of said asset transmitter with said WLAN while maintaining normal operation with other associated units of said WLAN. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of operating a wireless local area network (WLAN), comprising:
-
detecting via a sniffer circuit of an asset transmitter, whether or not a WLAN transmission is occurring; in response to detecting that said WLAN transmission is not occurring, transmitting a broadcast/multicast presence signal from said asset transmitter, wherein said presence signal is transmitted on one or more channels of said WLAN, to which no receiving unit in the WLAN can make a response and for which no association with another unit of said WLAN is required; receiving said presence signal at one or more access points of said WLAN, said access points operating according to a revision of the IEEE 802.11 specification; determining a received signal strength of said presence signal at each of said one or more access point; and
evaluating whether said asset transmitter is present in the vicinity of said one or more access points in conformity with said received signal strength, whereby said presence signals can be detected by said access points without association of said asset transmitter with said WLAN while maintaining normal operation with other associated units of said WLAN. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
-
19. A node for interacting with a wireless local area network (WLAN), comprising:
-
a transmitter for transmitting a broadcast/multicast presence signal, wherein said presence signal is transmitted on one or more channels of said WLAN, to which no receiving unit in the WLAN can make a response and for which no association with another unit of said WLAN is required; a sniffer for detecting whether or not WLAN signals are present in said WLAN; and a control circuit having an input coupled to an output of said sniffer and an output coupled to said transmitter for causing said transmitter to transmit said presence signal only when said sniffer detects that WLAN signals are not present. - View Dependent Claims (20)
-
Specification
-
- Resources
Litigation Campaign Assessment
Thank you for your request. You will receive a custom alert email when the Litigation Campaign Assessment is available.
×
Litigation Data
-
Current AssigneeAeroscout Limited (Stanley Black & Decker, Inc.)
-
Original AssigneeAeroscout Limited (Stanley Black & Decker, Inc.)
-
InventorsAljadeff, Daniel, Amsalem, Reuven
-
Primary Examiner(s)Tweel, Jr.; John A
-
Application NumberUS11/124,998Publication NumberTime in Patent Office1,443 DaysField of Search340/572.1, 340/825.49, 340/573.1, 340/10.1, 340/10.3, 342/357.07, 342/357.09US Class Current340/572.1CPC Class CodesH04W 4/02 Services making use of loca...H04W 64/00 Locating users or terminals...H04W 84/12 WLAN [Wireless Local Area N...H04W 84/18 Self-organising networks, e...
