ASYNCHRONOUS WIRELESS COMMUNICATION SYSTEM
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Abstract
The invention relates to an asynchronous wireless communication system, such as a UMTS system. The various base stations of an asynchronous wireless communication system do not typically have known timing offsets Tb(i), and these timing offsets vary with time. The invention allows the calculation of the difference dTb(i,j) between timing offsets Tb(i), Tb(j) for pairs of base stations B(i), B(j), using the timing of signals received by one or more wireless communication units. Having eliminated the timing offsets between the base stations as a variable, geo-location techniques from synchronous networks may then be used to locate wireless communication units in the asynchronous wireless communication system.
24 Citations
28 Claims
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1-14. -14. (canceled)
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15. A method for determining the differences dTb(i,j) between base station timing offsets Tb(i), Tb(j) for pairs of base stations B(i), B(j) in an asynchronous wireless communication system, comprising the steps of:
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using measurements Tm(i), Tm(j) of the timing of signals received by one or more wireless communication units from one or more pairs of base stations B(i), B(j) to derive estimates of the locations of the one or more communication units; and using the estimates of the locations to refine a set of estimates of differences dTb(i,j) between base station timing offsets Tb(i), Tb(j). - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. An asynchronous wireless communication system, adapted to determine the differences dTb(i,j) between base station timing offsets Tb(i), Tb(j) for pairs of base stations B(i), B(j), comprising:
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a processor for converting measurements Tm(i), Tm(j) of the timing of signals received by one or more wireless communication units from one or more pairs of base stations B(i), B(j) into estimates of the locations of the one or more communication units, and wherein the estimates of the locations are used for refining a set of estimates of differences dTb(i,j) between base station timing offsets Tb(i), Tb(j).
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28. An asynchronous wireless communication system, comprising:
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one or more wireless communication units; a network of base stations); and a processor or workstation for; (i) receiving measurements Tm(i), Tm(j) of the timing of signals received by one or more wireless communication units (410) from one or more pairs of base stations B(i),B(j); (ii) calculating the differences dTb(i,j) between base station timing offsets Tb(i), Tb(j) for pairs of base stations B(i), B(j); (iii) iteratively correcting the differences dTb(i,j) to derive a final set of differences dTb(i,j); and (iv) applying a synchronous geo-location technique to the final set of differences dTb(i,j), to geo-locate one or more of the wireless communication units.
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Specification