Mobile location estimation in a wireless communication system
First Claim
1. A method of estimating mobile station location in a wireless communication system in which a mobile station communicates with a primary base station associated with a primary location processor, the method comprising the steps of:
- transmitting from the primary base station a message signal directing the mobile station to trait a predetermined location signal, wherein the message signal comprises a fake handoff message generated in the primary base station in response to receipt of a mobile location service request, and the fake handoff message directs the mobile station to handoff from the primary station to the primary base station;
detecting the predetermined location signal in the primary base station to generate a first path delay measurement;
receiving additional path delay measurements generated by detecting the predetermined location signal in a plurality of secondary base stations; and
utilizing the first and additional delay measurements to estimate the location of the mobile station.
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Accused Products
Abstract
Methods and apparatus for estimating mobile station location in a wireless communication system. At initiation of a call or a page response, a mobile station of the system sends an access request signal to a primary base station. The primary base station responds with an access acknowledgment which may be intentionally delayed such that the mobile station increases its transmit power level. The primary base station then transmits a channel assignment message to the mobile station. The mobile station responds by transmitting a location signal in the form of a known user-specific traffic preamble at the higher transmit power level. The primary base station intentionally delays sending an acknowledgment of the preamble, such that the mobile station transmits the preamble for a longer period of time than it would otherwise. This additional transmission time allows the preamble to be detected accurately in the primary base station as well as in a number of other surrounding base stations in a manner suitable for generating path delay measurements. A primary location processor associated with the primary base station uses the path delay measurements from the primary and surrounding base stations to generate an estimate of mobile location. The mobile location estimation may be provided during an on-going call by the primary base station sending a fake handoff message to the mobile station directing it to handoff to the same base station and traffic channel but with a different power level and preamble length, or by the primary base station sending a predetermined location probe message directing the mobile station to transmit the traffic preamble with a desired power level and preamble length.
197 Citations
40 Claims
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1. A method of estimating mobile station location in a wireless communication system in which a mobile station communicates with a primary base station associated with a primary location processor, the method comprising the steps of:
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transmitting from the primary base station a message signal directing the mobile station to trait a predetermined location signal, wherein the message signal comprises a fake handoff message generated in the primary base station in response to receipt of a mobile location service request, and the fake handoff message directs the mobile station to handoff from the primary station to the primary base station; detecting the predetermined location signal in the primary base station to generate a first path delay measurement; receiving additional path delay measurements generated by detecting the predetermined location signal in a plurality of secondary base stations; and utilizing the first and additional delay measurements to estimate the location of the mobile station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for estimating mobile station location in a wireless communication system, the apparatus comprising:
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a primary base station for communicating with the mobile station, the primary base station transmitting a message signal directing the mobile station to transmit a predetermined location signal, and detecting the predetermined location signal in the primary base station to generate a first path delay measurement, wherein the message signal comprises a fake handoff message generated in the primary base station in response to receipt of a mobile location service request, and the fake handoff message directs the mobile station to handoff from the primary base station to the primary base station; and a primary location processor associated with the primary base station, the primary location processor receiving the first path delay measurement, receiving additional path delay measurements generated by secondary base stations which have detected the predetermined location signal, and utilizing the first and additional delay measurements to estimate the location of the mobile station. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An apparatus for estimating mobile station location in a wireless communication system, the apparatus comprising:
a mobile station operative to receive a message signal from a primary base station of the system, wherein the message signal comprises a fake handoff message generated in the primary base station in response to receipt of a mobile location service request, and the fake handoff message direct the mobile station to handoff from the primary base station to the primary base station, such that a predetermined location signal is detected in the primary base station and a number of secondary base stations in order to generate path delay measurements which can be processed to estimate the location of the mobile station. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
Specification