Estimating GPS time at cellular terminals based on timing of information from base stations and satellites
First Claim
1. A method for estimating GPS time in a mobile terminal that operates in a wireless communication system, the method comprising:
- generating at the mobile terminal a repository of cell-to-GPS timing data that is representative of a timing offset between GPS time and cell time for two or more cells with which the mobile terminal communicates;
identifying an originating cell of a received communication signal from a base station;
identifying timing advance data in the received communication signal, the timing advance data indicating distance between the mobile terminal and the base station;
estimating GPS time using the repository of cell-to-GPS timing data, the identity of the originating cell, the timing advance data, and a time indicator portion of the received communication signal.
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Accused Products
Abstract
A mobile terminal generates an estimate of GPS time. The mobile terminal includes a cellular receiver, a GPS receiver, and a processor. The cellular receiver is configured to receive communication signals from cells in a wireless communication system. The GPS receiver receives GPS signals and determines a GPS time reference therefrom. The processor estimates a cell time reference from the received communication signals, and generates cell-to-GPS timing data that represents a time offset between the cell time reference and the GPS time reference. The processor then estimates GPS time based on a time indicator portion of a received communication signal and the cell-to-GPS timing data. The estimated GPS time may be used by the GPS receiver to acquire GPS signals.
74 Citations
18 Claims
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1. A method for estimating GPS time in a mobile terminal that operates in a wireless communication system, the method comprising:
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generating at the mobile terminal a repository of cell-to-GPS timing data that is representative of a timing offset between GPS time and cell time for two or more cells with which the mobile terminal communicates; identifying an originating cell of a received communication signal from a base station; identifying timing advance data in the received communication signal, the timing advance data indicating distance between the mobile terminal and the base station; estimating GPS time using the repository of cell-to-GPS timing data, the identity of the originating cell, the timing advance data, and a time indicator portion of the received communication signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for estimating GPS time in a mobile terminal that operates in a wireless communication system, the method comprising:
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operating the mobile terminal on a communication channel in a cell in the wireless communication system, the communication channel having a cell time reference; receiving timing advance data from a base station via the communication channel, the timing advance data indicating distance between the mobile terminal and the base station; receiving a GPS communication signal at the mobile terminal, the GPS communication signal having a GPS time reference; determining in the mobile terminal cell-to-GPS timing data that is representative of a timing offset between the cell time reference and the GPS time reference; and estimating in the mobile terminal a GPS time based on a time indicator portion of the communication channel, the timing advance data, and the cell-to-GPS timing data. - View Dependent Claims (9, 10)
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11. A method for estimating GPS time in a mobile terminal that operates in a wireless communication system, the method comprising:
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operating the mobile terminal on a communication channel in a cell in the wireless communication system, the communication channel having a time reference; receiving timing advance data on the communication channel, wherein the timing advance data is indicative of distance between the mobile terminal and a base station that is servicing the communication channel; determining a time reference for the base station based on the timing advance data and the time reference of the communication channel; receiving a GPS communication signal at the mobile terminal, the GPS communication signal having a GPS time reference; generating cell-to-GPS timing data at the mobile terminal that is representative of a timing offset between the time reference for the base station and the GPS time reference; and estimating GPS time based on the cell-to-GPS timing data and a time indicator portion of a communication signal from the base station. - View Dependent Claims (12)
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13. A mobile terminal comprising:
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a receiver that is configured to receive communication signals from cells in a wireless communication system; a GPS receiver that is configured to receive GPS signals; a memory containing a repository of cell-to-GPS timing data that is representative of timing offset between GPS time and cell time for two or more cells; and a processor that is configured to identify an originating cell of a received communication signal from a base station, and is configured to estimate GPS time using the repository of cell-to-GPS timing data, the identity of the originating cell, and a time indicator portion of the received communication signal, and timing advance data that indicates distance between the mobile terminal and the base station. - View Dependent Claims (14, 15, 16, 17)
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18. A mobile terminal comprising:
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a receiver that is configured to receive communication signals from cells in a wireless communication system; a GPS receiver that is configured to receive GPS signals, and is configured to determine a GPS time reference from the received GPS signals; and a processor that is configured to estimate a cell time reference from the received communication signals, and is configured to determine a time reference for a base station based on the cell time reference and timing advance data from the base station, and is configured to generate cell-to-GPS timing data that is representative of a time offset between the time reference for the base station and the GPS time reference, and is configured to estimate a GPS time based on a time indicator portion of a received communication signal and the cell-to-GPS timing data.
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Specification