Polaris Wireless, Inc.

Tera Research Incorporated

David Stevenson Spain, Jr

Robert Lewis Martin

Scot Douglas Gordon

Martin J Feuerstein

Tarun Kumar Bhattacharya

Robert Morris Dressler

Hassan Mohamed El-Sallabi

Luis Perez-Breva

Jerome Arthur Blaha, Jr

Mahesh B Patel

Ankit Bansal

Manlio Allegra

Ronald J Kane

A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are location-dependent traits of electromagnetic signals. In environments where multiple antennas are radiating the same signal, as in the case of distributed antennas or host-repeater configurations, one or more possible locations of the wireless terminal can be designated as improbable based on i) a measure of the propagation delay of a signal traveling between a) a base station and b) the wireless terminal or an infrastructure antenna, or ii) the maximum distance at which a signal is detectable by the wireless terminal. Additionally, the applicable set of values for the location-dependent traits is selected based on similar criteria.

Estimating the location of a wireless terminal in wireless telecommunications systems that comprise distributed and/or repeater antennas

A method and system that account for one or more propagation-time components in a transmission path between a base station and a wireless terminal in a coverage area being served by the system. One such component is in the base station equipment between the radio that serves a wireless terminal and the antenna element that radiates and/or receives electromagnetic signals that involve the terminal. Another component of the transmission path is the one or more paths over which a radiated signal travels between the base station antenna element and the wireless terminal. By accounting for these propagation components through the use of measurement data provided by possibly a large number of wireless terminals, a disclosed location engine is able to derive adjusted measurements that are more representative of the propagation-time characteristic being measured by the individual terminals. These adjusted measurements can then be used to estimate the location of a wireless terminal more accurately.

Determining a propagation-time adjustment for a wireless coverage area, based on information provided by wireless terminals

A technique for providing a location estimate of a mobile station, with increased accuracy. An unenhanced estimate of the location of a target mobile station is first obtained. A portable transmitter is then situated in an initial geographic area of interest defined by the unenhanced estimate. The portable transmitter is then tuned to transmit on a particular neighbor base station frequency being reported by the mobile station. When the portable transmitter is moved close enough to the target mobile station, the mobile station stops reporting the neighbor to the mobile's wireless telecommunications network, on account of the interference introduced by the portable transmitter being on that frequency. The estimated distance from the portable transmitter to the target mobile station depends on the transmit signal strength used by the portable transmitter. By considering these details, an enhanced estimate of the location of the mobile station can then be deduced.

Estimating proximity to a mobile station by manipulating an interfering signal

A technique for deriving timing information across wireless base stations is disclosed. After initializing values for base station time-offset parameters, a server acquires reference coordinates of a wireless terminal, which are provided from an independent source, and also acquires values for one or more time-of-occurrences of events associated with signals that travel between the wireless terminal and the base stations. The server generates predicted coordinates of the wireless terminal, based in part on the current time-offset values, by using trilateration. The server then generates updated time-offset values, based on a method of least squares, in which each residual is a difference between the reference and predicted coordinates of each wireless terminal location, for one or more wireless terminals. The server modifies the time-offset values so as to minimize the least-squares function.

Base station timing derived from wireless terminal information

A technique for providing a location estimate of a mobile station, with increased accuracy. An unenhanced estimate of the location of a target mobile station is first obtained. A portable transmitter is then situated in an initial geographic area defined by the unenhanced estimate. The transmitter is then tuned to transmit a particular identifier on a particular frequency. When the transmitter is moved close enough to the mobile, the mobile starts reporting the identifier to the mobile's wireless network. Because the identifier and frequency are carefully selected so as not into interfere with ongoing operations of the wireless network, the wireless network itself merely regards the reported data to be invalid for handoff purposes. The estimated distance from the transmitter to the mobile depends on the transmit signal strength used by the transmitter. By considering these details, an enhanced estimate of the location of the mobile can then be deduced.

Estimating proximity to a mobile station by manipulating a signal that is decodable, but unexpected in the wireless network serving the mobile station

An apparatus and method are disclosed for tracking a large number of wireless terminals and for estimating the location of the terminals at each instant. Some embodiments of the present invention use a wide variety of factors to determine the order and frequency with which each wireless terminal is located. These factors include, but are not limited to, the history of the location of the wireless terminal, the time of day, and the weather.

Tracking large numbers of wireless terminals

A location engine that accounts for propagation-time components in an antenna system disposed between i) the base station that serves a wireless terminal and ii) the airwaves over which electromagnetic signals propagate between the antenna elements and wireless terminal. By considering and accounting for these propagation components, the location engine is able to estimate information about the antenna system, such as i) whether the antenna system is a distributed antenna system and ii) the configuration of the antenna system. Based on this estimated information, the location engine is also able to estimate adjustments that can be made to location-related measurements, and, with these adjustments, estimate the location of one or more wireless terminals.

Growing community of inventors

Portola Valley, CA, United States of America

David Stevenson Spain, Jr