Time synchronisation for mobile systems
First Claim
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1. A method of maintaining time synchronisation of a mobile terminal, of a telecommunications network, said mobile terminal having a low speed clock and a high speed clock;
- wherein the low speed clock is at least partly maintained in synchronisation with a clock of a remote station by utilising the time of arrival of signal bursts from said remote station.
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Abstract
A method of maintaining time synchronisation of a mobile terminal, of a telecommunications network, said mobile terminal having high speed and low speed clocks, in a deep sleep mode, comprising: when a deep sleep mode is entered, making an initial measurement to establish a frequency relationship between the high speed and low speed clocks, entering a deep sleep mode in which the high speed clock is deactuated, and updating said correlation based on the time of arrival of paging blocks, timed by the low speed clock.
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Citations
21 Claims
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1. A method of maintaining time synchronisation of a mobile terminal, of a telecommunications network, said mobile terminal having a low speed clock and a high speed clock;
- wherein the low speed clock is at least partly maintained in synchronisation with a clock of a remote station by utilising the time of arrival of signal bursts from said remote station.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16)
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8. A method as claimed in preceding claim, wherein an initial measurement is done over a period of at least 500 ms, to establish initial synchronisation of the low speed clock.
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9. A method as claimed in preceding claim, wherein, in a mobile telephone system, if a mobile terminal is unable to decode a paging block for timing correlation, it utilises a secondary recovery mechanism.
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17. A method of maintaining time synchronisation of a mobile terminal, having high speed and low speed clocks, in a deep sleep mode, comprising;
- making an initial measurement to establish a frequency relationship between the high speed and low speed clocks, entering deep sleep mode, waking the terminal and measuring timing correlation peak offsets between a network high speed clock and the low speed clock of the mobile terminal, and using the correlation peak offset values to correct for frequency drift of the low speed clock.
- 18. A mobile terminal, of a telecommunications network, the terminal comprising a high speed clock and a low speed clock, and means for maintaining the low speed clock in synchronisation by measuring and utilising the time of arrival of signal bursts from an external station.
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20. A method of maintaining time synchronisation of a mobile terminal, substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.
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21. A mobile terminal substantially as a method of maintaining time synchronisation of a mobile terminal, substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings
Specification