Virtual reference timing for multi-time based systems
A timing-reference circuit is employed by a multi-time-based system in which a timing reference is required for system processing. The timing-reference circuit may be used in a wireless receiver in which one or more transmitted signals are received as multipath signals, each corresponding to a different time reference. The timing-reference circuit is configured for selecting at least one received signal in a set of multipath signals as a timing reference, tracking the timing reference with a virtual timing reference, and synchronizing receiver processing to the virtual timing reference, even when the actual timing reference from which the virtual reference was derived vanishes. The timing-reference circuit provides for re-acquisition of a new timing reference when the virtual reference no longer qualifies as a timing reference.
1 . A timing-reference circuit employed in a receiver configured for receiving multipath signals, the timing-reference circuit configured for selecting at least one received signal in the multipath signals as a timing reference, tracking the timing reference with a virtual timing reference, and synchronizing receiver processing to the virtual timing reference.
2 . The timing reference circuit recited in claim 1 , wherein the timing-reference circuit comprises a clock.
3 . The timing reference circuit recited in claim 1 , further configured for implementing a timing-reference algorithm that determines whether the virtual timing reference is a satisfactory reference.
4 . The timing reference circuit recited in claim 3 , wherein the timing-reference algorithm is further configured for selecting a new received signal as the timing reference and tracking the new timing reference with the virtual timing reference.
5 . The timing reference circuit recited in claim 1 , further configured to advance or retard the virtual timing reference toward the timing-reference signal.
6 . A timing-reference method employed in a receiver configured for receiving a multipath signal, the method comprising:
providing for selecting at least one received signal in the multipath signal as a timing reference,
providing for tracking the timing reference with a virtual timing reference, and
providing for synchronizing receiver processing to the virtual timing reference.
7 . The method recited in claim 6 , wherein providing for tracking comprises locking a clock to the timing reference.
8 . The method recited in claim 6 , further comprising providing for implementing a timing-reference algorithm that determines whether the virtual timing reference is a satisfactory reference.
9 . The method recited in claim 8 , further comprising providing for selecting a new received signal as the timing reference and tracking the new timing reference with the virtual timing reference.
10 . The method recited in claim 6 , wherein providing for tracking further comprises advancing or retarding the virtual timing reference toward the timing-reference signal.
11 . A timing-reference system for a receiver configured to receive a multipath signal, the timing-reference system comprising:
a selection means configured for selecting at least one received signal in the multipath signal as a timing reference,
a tracking means configured for tracking the timing reference with a virtual timing reference, and
a synchronization means configured for synchronizing receiver processing to the virtual timing reference.
12 . The system recited in claim 11 , wherein the tracking means is configured for locking a clock to the timing reference.
13 . The system recited in claim 11 , wherein the tracking means is further configured for implementing a timing-reference algorithm that determines whether the virtual timing reference is a satisfactory reference.
14 . The system recited in claim 13 , wherein the selection means is further configured for selecting a new received signal as the timing reference and tracking the new timing reference with the virtual timing reference.
15 . The method recited in claim 11 , wherein the tracking means is further configured for advancing or retarding the virtual timing reference toward the timing-reference signal.