Method and apparatus for acquiring a pilot signal in a CDMA receiver
First Claim
1. A method for acquiring a pilot signal in a code division multiple access (CDMA) receiver, the CDMA receiver including at least one receiver finger, the method comprising the steps of:
- storing a predetermined number of samples of a received signal;
incrementing a real time linear sequence generator (RT LSG);
loading a state of the RT LSG into a non-real time LSG (NRT LSG) at a particular point in time relative to storing the predetermined number of samples;
repetitively correlating stored samples and contents of the NRT LSG, producing correlations;
incrementing the NRT LSG after correlating to establish an NRT LSG alignment value;
selecting a set of best correlations;
providing an NRT LSG alignment value which corresponds to one of the set of best correlations to a finger linear sequence generator associated with the at least one receiver finger; and
detecting the received signal at the at least one receiver finger using the finger linear sequence generator.
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0 Petitions
Accused Products
Abstract
A searcher receiver (114) includes a sample buffer (202) which stores signal samples loaded using a real time clock. A real time linear sequence generator (RT LSG) (206) stores an initial state and is clocked using the real time clock. The contents of the RT LSG are loaded into a non-real time linear sequence generator (NRT LSG) (208) when sample processing begins. Samples are correlated using a non-real time clock to allow signal processing to be uncoupled from the chip rate. The analog front end (108) may be powered down or tuned to another frequency during non-real time processing.
65 Citations
27 Claims
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1. A method for acquiring a pilot signal in a code division multiple access (CDMA) receiver, the CDMA receiver including at least one receiver finger, the method comprising the steps of:
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storing a predetermined number of samples of a received signal; incrementing a real time linear sequence generator (RT LSG); loading a state of the RT LSG into a non-real time LSG (NRT LSG) at a particular point in time relative to storing the predetermined number of samples; repetitively correlating stored samples and contents of the NRT LSG, producing correlations; incrementing the NRT LSG after correlating to establish an NRT LSG alignment value; selecting a set of best correlations; providing an NRT LSG alignment value which corresponds to one of the set of best correlations to a finger linear sequence generator associated with the at least one receiver finger; and detecting the received signal at the at least one receiver finger using the finger linear sequence generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A radiotelephone operable in a communication system, the radiotelephone comprising:
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a rake receiver including a plurality of receiver fingers; a searcher receiver including; a buffer for storing a plurality of samples of a received pilot signal; a non-real time linear sequence generator (NRT LSG) for generating a sequence of values, the NRT LSG incrementing in response to a clock signal; a correlator for correlating the plurality of samples and the sequence of values and producing a correlation result; and a timing reference for maintaining a real time reference, the timing reference providing the real time reference to the NRT LSG when a first sample is stored in the buffer, the searcher receiver detecting the received pilot signal to acquire system timing for the radiotelephone. - View Dependent Claims (12, 13, 14)
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15. A method for updating rake receiver finger assignments in a code division multiple access (CDMA) receiver, the method comprising the steps of:
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(a) initializing a timing reference, storing a timing reference value; (b) collecting a predetermined number of pilot signal samples; (c) incrementing a non-real-time linear sequence generator (NRT LSG) to produce a sequence of values; (d) correlating the predetermined number of pilot signal samples and the sequence of values, producing correlation results; (e) repeating steps (c) and (d) a predetermined number of times; (f) assigning receiver fingers based on the correlation results; (g) shifting the NRT LSG to a next state; and (h) repeating steps (b)-(g) until all pilot signals of interest have been processed. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification