System and method for determining the location of a mobile station in a wireless network
First Claim
1. For use in a wireless network comprising a plurality of base stations capable of communicating with a plurality of mobile stations, a mobile station locating system associated with a first one of said plurality of base stations for determining the location of a first one of said plurality of mobile stations, said mobile station position locating system comprising:
- a timer capable of measuring a first round trip delay time associated with a position locator message transmitted from said first base station to said first mobile station and a position locator acknowledgment message transmitted from said first mobile station back to said first base station;
a power monitor capable of measuring a power level of said position locator acknowledgment message received by said first base station and determining that said received power level has saturated a receiver associated with said first base station; and
a data processor coupled to said timer and to said power monitor capable of causing said first base station to transmit at least one power control message to said first mobile station capable of causing said first mobile station to increase a transmission power level of said position locator acknowledgment message, said increased transmission power level causing said receiver to saturate, wherein said data processor, in response to a determination that said first base station receiver has saturated, calculates from said first round trip delay time a first distance between said first mobile station and said first base station.
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Abstract
There is disclosed a mobile station locating system for use in a wireless network comprising a group of base stations that communicate with mobile stations. The mobile station locating system comprises: 1) a timer for measuring a first round trip delay time between a position locator message transmitted from the first base station to the first mobile station and a position locator acknowledgment message transmitted from the first mobile station back to the first base station; 2) a power monitor for measuring a power level of the position locator acknowledgment message received by the first base station and determining that the received power level has saturated a receiver in the first base station; and 3) a data processor coupled to the timer and to the power monitor that causes the first base station to transmit power control messages to the first mobile station. The power control messages cause the first mobile station to increase the transmission power level of the position locator acknowledgment message. The increased transmission power level cause the receiver to saturate. The data processor, in response to a determination that the first base station receiver has saturated, calculates from the first round trip delay time a first distance between the first mobile station and the first base station.
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Citations
21 Claims
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1. For use in a wireless network comprising a plurality of base stations capable of communicating with a plurality of mobile stations, a mobile station locating system associated with a first one of said plurality of base stations for determining the location of a first one of said plurality of mobile stations, said mobile station position locating system comprising:
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a timer capable of measuring a first round trip delay time associated with a position locator message transmitted from said first base station to said first mobile station and a position locator acknowledgment message transmitted from said first mobile station back to said first base station;
a power monitor capable of measuring a power level of said position locator acknowledgment message received by said first base station and determining that said received power level has saturated a receiver associated with said first base station; and
a data processor coupled to said timer and to said power monitor capable of causing said first base station to transmit at least one power control message to said first mobile station capable of causing said first mobile station to increase a transmission power level of said position locator acknowledgment message, said increased transmission power level causing said receiver to saturate, wherein said data processor, in response to a determination that said first base station receiver has saturated, calculates from said first round trip delay time a first distance between said first mobile station and said first base station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A wireless network comprising a plurality of base stations capable of communicating with a plurality of mobile stations, wherein a first one of said plurality of base stations comprises:
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a mobile station locating system capable of determining the location of a first one of said plurality of mobile stations, said mobile station position locating system comprising;
a timer capable of measuring a first round trip delay time associated with a position locator message transmitted from said first base station to said first mobile station and a position locator acknowledgment message transmitted from said first mobile station back to said first base station;
a power monitor capable of measuring a power level of said position locator acknowledgment message received by said first base station and determining that said received power level has saturated a receiver associated with said first base station; and
a data processor coupled to said timer and to said power monitor capable of causing said first base station to transmit at least one power control message to said first mobile station capable of causing said first mobile station to increase a transmission power level of said position locator acknowledgment message, said increased transmission power level causing said receiver to saturate, wherein said data processor, in response to a determination that said first base station receiver has saturated, calculates from said first round trip delay time a first distance between said first mobile station and said first base station. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. For use in a wireless network comprising a plurality of base stations capable of communicating with a plurality of mobile stations, a method of determining the location of a first one of the plurality of mobile stations comprising the steps of:
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transmitting to the first mobile station from a first one of the base stations a plurality of position locator messages, wherein the plurality of position locator messages causes the first mobile station to transmit to the first base station a plurality of position locator acknowledgment messages;
transmitting to the first mobile station a plurality of power control messages, wherein the plurality of power control messages causes the first mobile station to transmit the plurality of position locator acknowledgment messages at progressively increasing levels of transmission power;
determining that at least one of the position locator acknowledgment messages received by the first base station has saturated a receiver in the first base station; and
in response to the determination that at least one of the position locator acknowledgment messages has saturated the receiver, measuring a first round trip delay time associated with a first position locator message and a first position locator acknowledgment message responding to the first position locator message; and
calculating from the first round trip delay time a first distance between the first mobile station and the first base station. - View Dependent Claims (18, 19, 20, 21)
transmitting to the first mobile station from a second one of the base stations a position locator message, wherein the position locator message causes the first mobile station to transmit to the second base station a position locator acknowledgment message;
measuring a second round trip delay time associated with the position locator message and the position locator acknowledgment message responding to the position locator message; and
calculating from the second round trip delay time a second distance between the first mobile station and the second base station.
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19. The method as set forth in claim 18 further comprising the step of determining from the first distance and the second distance the location of the first mobile station.
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20. The method as set forth in claim 19 further comprising the step of calculating a third distance between the first mobile station and a selected third base station, the step of calculating a third distance comprising:
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transmitting to the first mobile station from a third one of the base stations a position locator message, wherein the position locator message causes the first mobile station to transmit to the third base station a position locator acknowledgment message;
measuring a third round trip delay time associated with the position locator message and the position locator acknowledgment message responding to the position locator message; and
calculating from the third round trip delay time a third distance between the first mobile station and the third base station.
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21. The method as set forth in claim 20 further comprising the step of determining from the first distance, the second distance, and the third distance, the location of the first mobile station.
Specification