Method and arrangement for frequency synchronization of a mobile station with a base atation in a mobile communication system
AssigneeSt-Ericcson SA
InventorsMarkus Neumann, Wolfgang Wippich
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Abstract
In a method for synchronizing a mobile station with the base station in a mobile communication system, a reference-frequency oscillator is re-adjusted. To enable an inexpensive reference-frequency oscillator of simple construction to be used, the frequency variations resulting from a change in the temperature of the mobile station and a change in its location are determined and/or predicted separately. When the frequency variations are large, the mobile station is synchronized with the base station more frequently than when they are small.
Claims31
A method of synchronizing the carrier frequency of a mobile station with the carrier frequency of a base station in a cellular mobile communication system, a reference-frequency oscillator being re-adjusted by means of a final controlling element, characterized in that the frequency variation that occurs in the mobile station due to a change in the temperature of the mobile station and the frequency variation that occurs when there is a change in the location of the mobile station relative to the base station are determined and/or predicted separately, and in that, when a large frequency variation is determined and/or expected, the carrier frequency of the mobile station is synchronized with the carrier frequency of the base station, by means of an AFC algorithm, more frequently than is the case when a small frequency variation is determined and/or expected.
A mobile station with a reference-frequency oscillator being re-adjusted by means of a final controlling element, characterized in that the frequency variation that occurs in the mobile station due to a change in the temperature of the mobile station and the frequency variation that occurs when there is a change in the location of the mobile station relative to the base station are determined and/or predicted separately, and in that, when a large frequency variation is determined and/or expected, the carrier frequency of the mobile station is synchronized with the carrier frequency of the base station, by means of an AFC algorithm, more frequently than is the case when a small frequency variation is determined and/or expected.
A microprocessor for a mobile station, the microprocessor is provided for controlling a reference-frequency oscillator characterized in that the microprocessor is provided for determining and/or predicting separately the frequency variation that occurs in the mobile station due to a change in the temperature of the mobile station and the frequency variation that occurs when there is a change in the location of the mobile station relative to the base station and in that, when a large frequency variation is determined and/or expected, the microprocessor is provided for synchronizing the carrier frequency of the mobile station with the carrier frequency of the base station, by means of an AFC algorithm, more frequently than is the case when a small frequency variation is determined and/or expected.
Dependencies are inferred from the claim text.