Patent ID: 6169903
Filing Date: 2001-01-02
Classification: H04W

Abstract:
A method in a wireless communication system for determining a location which a subscriber unit is positioned, the method comprising the steps of:defining a plurality of sub-areas within a coverage area of the wireless communication system; positioning a plurality of transmitters within ones of the plurality of sub-areas, each transmitter positioned at a transmitter location; programming a memory, in at least one of the subscriber unit and a controller of the wireless communication system, with a plurality of unique transmitter identifiers and a corresponding plurality of transmitter locations; periodically transmitting a locator signal from the plurality of sub-areas during a plurality of time slots coordinated such that, within a sub-area, no more than one transmitter transmits during each of the plurality of time slots, the locator signal comprising one of the plurality of unique transmitter identifiers for identifying a transmitter from which the locator signal is sent; monitoring, by the subscriber unit, the locator signal to determine a plurality of propagation delays between the subscriber unit and ones of the plurality of transmitters received; and estimating, by one of the subscriber unit and the controller, the location of the subscriber unit from the plurality of propagation delays and the plurality of transmitter locations corresponding to the plurality of unique transmitter identifiers received.