Wireless local area network (WLAN) channel radio-frequency identification (RFID) tag system and method therefor
US6963289B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 18, 2002 |
| Grant date | Nov 8, 2005 |
| Priority date | — |
| Expiry date | Jul 2, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S13/765
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A wireless local area network (WLAN) radio-frequency identification (RFID) tag system provides location finding in a wireless local area network (WLAN), using a WLAN channel. Interference with the WLAN is prevented by either using a sniffer circuit to determine that no network transmission is in progress, using a modified coding sequence or preamble to cause standard WLAN receivers to ignore the RFID tag transmissions, or transmitting a message using a standard WLAN signal addressed to an address not corresponding to a unit within the WLAN. Location units (LUs) and a master unit (MU) within the WLAN receive the RFID tag transmissions and can determine the location of a tag by triangulation based on differences between the signals received at the location units from the tag. The master unit receives the signal information from the location units and computes the location of the tag. Time-difference-of-Arrival (TDOA), received signal strength indication (RSSI) or other triangulation techniques may be used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.