Location tracking using directional antennas combined with signal strength measurements

• US 20050159154A1
• Filed: 12/30/2003
• Published: 07/21/2005
• Est. Priority Date: 12/30/2003
• Status: Active Grant

• Current Assignee: Reflectivity, Inc. (Texas Instruments, Inc.), Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Goren, David P.
• Granted Patent: US 7,640,024 B2
• Time in Patent Office: Days
• US Class Current: 455/434
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A wireless local area network has mobile units which are provided with radios for transmitting and receiving data communications messages between the mobile units and fixed access points. The mobile units are located using signal strength for radio communications between the mobile units and the access points. At least some of the access points are provided with antennas having antenna patterns with selected pattern shape for enhancing location of the mobile units.

Claims

1. In a wireless local area network wherein mobile units are provided with radios for transmitting and receiving data communications messages between said mobile units and fixed access points, and wherein said mobile units are located using signal strength for radio communications between said mobile units and said access points, the improvement wherein at least some of said access points are provided with antennas having antenna patterns with selected pattern shape for enhancing location of said mobile units.

2. The improvement specified in claim 1 wherein said selected pattern shapes include horizontally offset directional antenna patterns.

3. The improvement as specified in claim 2 wherein said horizontally offset directional antenna patterns are horizontally offset in angular direction.

4. The improvement as specified in claim 1 wherein at least some of said antenna patterns offset in angular direction are provided by an antenna having multiple angularly offset beams

5. The improvement specified in claim 4 wherein said antennas having angularly offset beams are connected by a switch to a single access point circuit.

6. The improvement specified in claim 4 wherein said antennas having angularly offset beams are connected to multiple access point circuits.

7. The improvement specified in claim 4 wherein said antennas are mounted near the periphery of a facility.

8. The improvement as specified in claim 2 wherein said horizontally offset directional beams are horizontally offset in position.

9. The improvement as specified in claim 8 wherein at least some of said antennas are mounted near the periphery of a facility.

10. The improvement specified in claim 8 wherein said directional beams are offset in position to correspond to aisles in a facility.

11. The improvement specified in claim 1 wherein said antennas are located at selected heights for acheiving said selected pattern shapes.