Communications in an asynchronous cellular wireless network
AssigneeQUALCOMM Incorporated
InventorsJosef Blanz, Serge Willenegger
Life of this patent
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Abstract
Systems and techniques are disclosed for establishing a reference corresponding to the timing of a received signal from the first source, determining the timing for each received signal from a plurality of second sources, adjusting the reference to the timing of the received signal from one of the second sources, the timing of the received signal used to adjust the reference being closest in time to the unadjusted reference, and synchronizing a signal to the reference for transmission.
Claims19
A destination station for use in an asynchronous cellular communications system that includes a first substantially asynchronous source that transmits a first pilot signal frame over a first coverage region, a second substantially asynchronous source that transmits a second pilot signal frame over a second coverage region, and a third substantially asynchronous source that transmits a third pilot signal frame over a third coverage region that overlaps with at least the second coverage region, wherein the pilot signal frames transmitted from the first, second and third sources are substantially asynchronous, comprising:
- a memory;
- a processor that initially adds the first substantially asynchronous source to an active set stored in the memory;
- and
- a transmitter that, when in the first coverage region, transmits uplinik frames synchronized to the first pilot signal frame;
- when the processor removes the first substantially asynchronous source from the active set, wherein the processor:
- selects one of the second substantially asynchronous source and the third substantially asynchronous source, and
- resynchronizes the timing of the uplinik frames to the timing of downlinik frames from the one of the second pilot signal frame and the third pilot signal frame that is closest to the timing of the first pilot signal frame such that the amount of adjustment required to resynchronize is minimized.
An apparatus for selecting one of a plurality of substantially asynchronous sources as a synchronization source, comprising:
- a searcher configured to:
- establish a reference based on a first received signal from a first substantially asynchronous source,
- determine the timing of second received signals from a plurality of second substantially asynchronous sources,
- adjust the reference to the timing of one of the second received signals closest in timing to the unadjusted reference to thereby substantially minimize slewing, and
- synchronize to the reference for transmission,
- wherein the timing of the first received signal and the timing of the second received signals are substantially asynchronous.
An apparatus for selecting one of a plurality of substantially asynchronous sources as a synchronization source, comprising:
- a searcher configured to:
- establish a reference corresponding to the start of a frame of a first received signal from a first substantially asynchronous source,
- determine the timing for each of a plurality of second received frames from a plurality of second substantially asynchronous sources, wherein the timing of the frames of the first received signal and the timing of the frames of second received signals are substantially asynchronous,
- adjust the reference to the start of the frame of one of the second received signals that is closest to the timing of the unadjusted reference to thereby substantially minimize slewing, and
- synchronize a signal to the reference for transmission.
Dependencies are inferred from the claim text.