The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 18, 2011
Filed:
Jun. 28, 2007
Ajay Malik, Santa Clara, CA (US);
Vinh-phuong Le, Fremont, CA (US);
Mahender Vangati, San Jose, CA (US);
Ajay Malik, Santa Clara, CA (US);
Vinh-Phuong Le, Fremont, CA (US);
Mahender Vangati, San Jose, CA (US);
Symbol Technologies, Inc., Holtsville, NY (US);
Abstract
Methods and systems are provided for determining the location of a first wireless device (e.g., a mobile unit) within a wireless network comprising a plurality of second wireless devices (e.g., access points). The method includes identifying an overlap area corresponding to the intersection of RF ranges for the one or more second wireless devices then computing a set of signal strength values, each associated with a measure of RF signal strength (e.g., RSSI) received by the plurality of second wireless devices from the first wireless device. A decision metric is evaluated for a plurality of locations within the overlap area based on the set of signal strength values. The location of the first wireless device is determined by selecting, from the plurality of locations, a location having the optimum value of the decision metric within the overlap area. The decision metric may utilize a minimum mean square error (MMSE) calculation. A weighting function may be used to remove redundant or weak signal strength values. The systems and methods are applicable, for example, to networks operating in accordance with 802.11, RFID, WiMax, WAN, Bluetooth, Zigbee, UWB, and the like.