Method and apparatus for synchronization
AssigneeNokia Mobile Phones Ltd.
InventorsIlkka Niva, Kaj Jansen, Kjell Ostman
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Abstract
The present invention provides a method and a device in which two or more fingers of a RAKE receiver can locked to a multipath received signal in a situation of a fat finger impulse response. One embodiment of the present invention assigns two RAKE fingers to an impulse response so that one finger tracks the impulse response with an Early-Ontime DLL method and the other finger is tracking the impulse response with an Ontime-Late DLL method. The method comprises detecting the delay between the received signal and a delayed version, comparing the delay with a pre-determined threshold and when the delay falls below the threshold, changing the tracking method of the delayed version of the received signal to a second tracking method.
Claims11
A method for synchronizing a receiver comprising the steps of:
- tracking a received signal by a first receiver branch using a first tracking method with the signal being sampled at a first sampling time;
- tracking a delayed version of the received signal by a second receiver branch using the first tracking method, the signal being sampled at a second sampling time;
- detecting the delay between the received signal and a delayed version thereof;
- comparing the delay with a pre-determined threshold and when the delay falls below the threshold, tracking the delayed version of the received signal by a second tracking method;
- and
- wherein the first and second tracking methods differ from each other in that for a common input the first and second tracking methods have at least partially different sampling instances.
A device for synchronizing a receiver comprising:
- a converter for sampling the received signal and a delayed version thereof, a first receiver branch for tracking the received signal using a first tracking method with the signal being sampled at a first sampling time, a second receiver branch for tracking a delayed version of the received signal using the first tracking method with the signal being sampled at a second sampling time, means for determining a delay between the received signal and the delayed version thereof, means for comparing the time delay with a pre-determined threshold and means for changing the tracking method for a delayed version of the received signal to a second tracking method;
- and
- wherein the first and second tracking methods differ from each other in that for a common input the first and second tracking methods have at least partially different sampling instances.
Dependencies are inferred from the claim text.