System and method for performing symbol boundary-aligned search of direct sequence spread spectrum signals
First Claim
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1. A method for processing a received sequence comprising:
- receiving a hypothesis;
determining a start and a stop condition;
selecting samples from the received sequence based on the start condition; and
providing the samples and hypothesis to a correlator, wherein the start condition aligns the samples and hypothesis on a symbol boundary.
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Abstract
System and method for performing symbol boundary aligned searches of signals. A preferred embodiment comprises a search control unit (such as search control unit 725) that can determine a start and stop condition for a correlation based on a hypothesis, a searcher (such as searcher 705) which includes a multiplexer that can select a subset of samples of a received sequence based on the hypothesis and start and stop conditions. The search control unit can then wait for the occurrence of the start condition and assign the hypothesis to a correlator, which will correlate the subset of samples with a locally generated pseudo-random number sequence based upon the hypothesis.
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Citations
25 Claims
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1. A method for processing a received sequence comprising:
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receiving a hypothesis; determining a start and a stop condition; selecting samples from the received sequence based on the start condition; and providing the samples and hypothesis to a correlator, wherein the start condition aligns the samples and hypothesis on a symbol boundary. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A circuit comprising:
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a search control unit coupled to a hypothesis memory, the search control unit containing circuitry to provide a start and stop condition for a correlation based on a hypothesis read from the hypothesis memory; a searcher coupled to the search control unit, the searcher containing circuitry to select a subset of samples from a received sequence based on instructions from the search control unit, correlate the subset of samples with a pseudo-random number sequence, and accumulate the correlation results; and a sequence generator coupled to the search control unit and the searcher, the sequence generator containing circuitry to generate the pseudo-random number sequence based on the hypothesis; wherein the searcher comprises; a multiplexer coupled to a received sequence input, the multiplexer containing circuitry to select the subset of samples from the received sequence based on the start and stop condition provided by the search control unit; a descrambler coupled to the multiplexer and the sequence generator, the descrambler containing circuitry to correlate the subset of samples from the multiplexer with the pseudo-random number sequence from the sequence generator; and an accumulator coupled to the descrambler, the accumulator containing circuitry to coherently and non-coherently accumulate the correlation results. - View Dependent Claims (16, 17, 18)
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19. A circuit comprising:
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a search control unit coupled to a hypothesis memory, the search control unit containing circuitry to provide a start and stop condition for a correlation based on a hypothesis read from the hypothesis memory; a searcher coupled to the search control unit, the searcher containing circuitry to select a subset of samples from a received sequence based on instructions from the search control unit, correlate the subset of samples with a pseudo-random number sequence, and accumulate the correlation results; and a sequence generator coupled to the search control unit and the searcher, the sequence generator containing circuitry to generate the pseudo-random number sequence based on the hypothesis; wherein the hypothesis stored in the hypothesis memory is stored as a set of search parameters, and wherein the hypothesis is derived from the set of search parameters and a timing reference.
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20. A wireless device comprising:
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an analog front end coupled to an antenna, the analog front end containing circuitry to filter and amplify a received signal provided by the antenna; an analog-to-digital converter (ADC), the ADC to convert an analog signal provided by the analog front end into a digital symbol stream; a search unit coupled to the ADC, the search unit containing circuitry to test hypotheses, wherein the tests are performed such that each hypothesis is aligned along symbol boundaries; and a processing unit coupled to the ADC, the processing unit containing circuitry to error detect and correct, decode and despread, and filter the digital symbol stream. - View Dependent Claims (21, 22, 23)
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24. A wireless device comprising:
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an analog front end coupled to an antenna, the analog front end containing circuitry to filter and amplify a received signal provided by the antenna; an analog-to-digital converter (ADC), the ADC to convert an analog signal provided by the analog front end into a digital symbol stream; a search unit coupled to the ADC, the search unit containing circuitry to test hypotheses, wherein the tests are performed along symbol boundaries; and a processing unit coupled to the ADC, the processing unit containing circuitry to error detect and correct, decode and despread, and filter the digital symbol stream; wherein the search unit comprises; a search control unit coupled to a hypothesis memory, the search control unit containing circuitry to provide a start and stop condition for a correlation based on a hypothesis read from the hypothesis memory; a searcher coupled to the search control unit, the searcher containing circuitry to select a subset of samples from a received sequence based on instructions from the search control unit, correlate the subset of samples with a pseudo-random number sequence, and accumulate the correlation results; and a sequence generator coupled to the search control unit and the searcher, the sequence generator containing circuitry to generate the pseudo-random number sequence based on the hypothesis. - View Dependent Claims (25)
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Specification