Method and apparatus for acquiring and tracking pilots in a CDMA communication system
First Claim
1. In a wireless communication system, a method of acquiring signal instances in a received signal, comprising:
- acquiring a frequency of each of a plurality of candidate signal instances with a respective first frequency control loop at a receiver;
detecting acquisition on at least two of the plurality of candidate signal instances; and
tracking an average frequency of the at least two acquired signal instances with a second frequency control loop, wherein the at least two acquired signal instances correspond to at least two multipaths suitable for combining at the receiver.
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Accused Products
Abstract
Techniques to acquire and track pilots in a CDMA system. In an aspect, frequency acquisition of a number of signal instances (i.e., multipaths) in a received signal may be achieved concurrently based on a frequency control loop (RAFC) maintained for each finger processor of a rake receiver. Upon successful acquisition, frequency tracking of acquired multipaths may be achieved based on a combination of a frequency control loop (VAFC) maintained for an oscillator used for downconverting the received signal and the RAFCs for the finger processors. In a tracking mode, the VAFC tracks the average frequency of the acquired multipaths by adjusting the frequency of the oscillator. The RAFC of each finger processor tracks the residual frequency error (e.g., due to Doppler frequency shift) of the individual acquired multipath by adjusting the frequency of a complex sinusoidal signal used in a rotator within the finger processor.
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Citations
46 Claims
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1. In a wireless communication system, a method of acquiring signal instances in a received signal, comprising:
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acquiring a frequency of each of a plurality of candidate signal instances with a respective first frequency control loop at a receiver; detecting acquisition on at least two of the plurality of candidate signal instances; and tracking an average frequency of the at least two acquired signal instances with a second frequency control loop, wherein the at least two acquired signal instances correspond to at least two multipaths suitable for combining at the receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A method of acquiring pilots in a code division multiple access (CDMA) communication system, comprising:
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acquiring a frequency of each of a plurality of candidate signal instances with a respective first frequency control loop at a receiver; detecting acquisition on at least two of the plurality of candidate signal instances, wherein the at least two acquired signal instances correspond to at least two multipaths suitable for combining at the receiver; transferring a frequency error of each of the at least two acquired signal instances from the first frequency control loop to a second frequency control loop; tracking an average frequency of the at least two acquired signal instances with the second frequency control loop; and tracking a residual frequency error between the average frequency and the frequency of each acquired signal instance with the first frequency control loop for the acquired signal instance. - View Dependent Claims (33)
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34. In a wireless communication system, a method of acquiring signal instances in a received signal, comprising:
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acquiring a frequency of each of a plurality of candidate signal instances at a receiver; detecting frequency acquisition on at least two of the plurality of candidate signal instances based on at least one detector, wherein the at least two acquired signal instances correspond to at least two multipaths suitable for combining at the receiver; performing system acquisition on an acquired signal instance having a best detector output among the at least two acquired signal instances; and retaining frequency acquisition information for each acquired signal instance for which system acquisition is not performed. - View Dependent Claims (35, 36)
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37. A receiver unit in a wireless communication system, comprising:
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a plurality of finger processors operative to acquire frequency of a plurality of candidate signal instances in a received signal with a plurality of first frequency control loops; at least one detector operative to detect acquisition on at least two of the plurality of candidate signal instances, wherein the at least two acquired signal instances correspond to at least two multipaths suitable for combining at the receiver unit; and a second frequency control loop operative to track an average frequency of the at least two acquired signal instances. - View Dependent Claims (38, 39, 40, 41)
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42. A terminal in a code division multiple access (CDMA) system comprising:
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a plurality of finger processors operative to acquire frequency of a plurality of candidate signal instances in a received signal with a plurality of first frequency control loops; at least out detector operative to detect acquisition on at least two of the plurality of candidate signal instances, wherein the at least two acquired signal instances correspond to at least two multipaths suitable for combining at the terminal; and a second frequency control loop operative to track an average frequency of the at least two acquired signal instances. - View Dependent Claims (43, 44, 45, 46)
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Specification