CELLULAR RADIO POSITIONING
First Claim
1. A method of determining the position of a mobile communications device within a cellular network, the method comprising the steps of:
- transmitting data to the mobile communication device from the cellular network, said data identifying to the mobile communication device a list of radio channels corresponding to respective radio transmitters of the cellular network, said list being determined on the basis of the approximate position of the mobile communication device; and
causing the mobile communication device to listen on said identified channels, or on other channels excluding said identified channels, and to determine from information transmitted over the listened to channels data values related to the relative geometry of the mobile communication device and the radio transmitters transmitting the listened to channels; and
determining the position of the mobile communication device using said determined data values.
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Accused Products
Abstract
A cellular radio network based positioning system for determining the position of a mobile station (16). For each base transceiver station (1 to 5) or cell of the network, a fixed list of base transceiver stations is stored by a Mobile Positioning Centre (13). Each list identifies those base transceiver stations which enable the position of a mobile station served by the corresponding base transceiver station (6) to be optimally determined. The list is transmitted to the mobile station (16) via the serving base transceiver station (6) and the mobile station determines an observed time difference for each of the listed base transceiver stations, relative to the serving base transceiver station (6), from signals broadcast by the listed base transceiver stations. The observed time differences are transmitted from the mobile station (6) to the serving base transceiver station (6) and are used by the network to compute the position of the mobile station (16).
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Citations
8 Claims
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1. A method of determining the position of a mobile communications device within a cellular network, the method comprising the steps of:
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transmitting data to the mobile communication device from the cellular network, said data identifying to the mobile communication device a list of radio channels corresponding to respective radio transmitters of the cellular network, said list being determined on the basis of the approximate position of the mobile communication device; and
causing the mobile communication device to listen on said identified channels, or on other channels excluding said identified channels, and to determine from information transmitted over the listened to channels data values related to the relative geometry of the mobile communication device and the radio transmitters transmitting the listened to channels; and
determining the position of the mobile communication device using said determined data values. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Apparatus for determining the position of a mobile communications device within a cellular network, the apparatus comprising:
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a base transceiver station for transmitting data to the mobile communication device from the cellular network, said data identifying to the mobile communication device a list of radio channels corresponding to respective radio transmitters of the cellular network, said list being determined on the basis of the approximate position of the mobile communication device;
a radio receiver at the mobile communication device for listening on said identified channels, or on other channels excluding said identified channels;
first signal processing means coupled to said radio receiver for determining from information transmitted over the listened to channels data values related to the relative geometry of the mobile communication device and the radio transmitters transmitting the listened to channels; and
second signal processing means for computing the position of the mobile communication device using said determined data values.
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8. A mobile communications device comprising:
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a radio receiver for receiving data transmitted from a serving base transceiver station of a cellular radio network, said data identifying to the mobile communication device a list of radio channels corresponding to respective radio transmitters of the cellular network, and said list being determined on the basis of the approximate position of the mobile communication device, and said radio receiver being arranged to listen on said identified channels, or on other channels excluding said identified channels;
first signal processing means coupled to said radio receiver for determining from information transmitted over the listened to channels data values related to the relative geometry of the mobile communication device and the radio transmitters transmitting the listened to channels; and
a radio transmitter for transmitting said determined data values to said serving base transceiver station.
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Specification