Signal analysis technique for determining a subject of binary sequences most likely to have been transmitted in a multi-node communication network
First Claim
1. An apparatus for analyzing a signal received at a receiving node of a multi-node communication network in order to determine a particular subset of binary sequences likely to have been transmitted by a transmitting node of said network, said particular subset being contained in a multi-member set of binary sequences available to said transmitting node, said transmitting node having actually transmitted a certain subset of binary sequences selected from said set of binary sequences available to said transmitting node, said particular subset thereby being determined with a high degree of probability to be the certain subset that was actually transmitted, said apparatus comprising:
- a) means for correlating each binary sequence in said set of binary sequences available to said transmitting node with said received signal to produce a set of correlation outputs, each correlation output corresponding to a specified one of said available binary sequences; and
b) means for evaluating said set of correlation outputs to identify said particular subset of said set of available binary sequences as being most likely to have been transmitted by said transmitting node, said means for evaluating said set of correlation outputs having;
(i) means for computing a largest sum of correlation outputs corresponding to a first subset of said set of binary sequences available to said transmitting node, and a next-largest sum of correlation outputs corresponding to a second subset of said set of binary sequences available to said transmitting node;
(ii) means for forming a ratio of said largest sum to said next-largest sum; and
(iii) means for evaluating said ratio to determine whether said ratio is greater than a predetermined threshold.
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Accused Products
Abstract
A method and apparatus are disclosed whereby a received signal comprising a binary spreading-code sequence, which belongs to a set of binary spreading-code sequences available to a transmitting node of a multi-node communication network, can be analyzed to determine the particular sequence from the set of sequences available to the transmitting node that was actually transmitted. All sequences of the set of available sequences have the property that each sequence can be generated by the same configuration of two linear feedback binary shift registers, where the feedback taps on the two binary shift registers correspond to primitive polynomials of the same degree over GF(2), the field of two elements. The received signal is correlated with each sequence of the set of available sequences to obtain a set of correlation values. The correlation values having the largest and the next-largest magnitudes are compared, and if their ratio exceeds a predetermined threshold, a detection decision is made. If the ratio does not exceed the predetermined threshold, additional logic is implemented to declare a detection decision or an erasure. Once a detection decision has been made, the signal is decoded into a block of information bits corresponding to the largest correlation magnitude. The sign of the corresponding correlation value determines one additional information bit.
48 Citations
8 Claims
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1. An apparatus for analyzing a signal received at a receiving node of a multi-node communication network in order to determine a particular subset of binary sequences likely to have been transmitted by a transmitting node of said network, said particular subset being contained in a multi-member set of binary sequences available to said transmitting node, said transmitting node having actually transmitted a certain subset of binary sequences selected from said set of binary sequences available to said transmitting node, said particular subset thereby being determined with a high degree of probability to be the certain subset that was actually transmitted, said apparatus comprising:
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a) means for correlating each binary sequence in said set of binary sequences available to said transmitting node with said received signal to produce a set of correlation outputs, each correlation output corresponding to a specified one of said available binary sequences; and b) means for evaluating said set of correlation outputs to identify said particular subset of said set of available binary sequences as being most likely to have been transmitted by said transmitting node, said means for evaluating said set of correlation outputs having; (i) means for computing a largest sum of correlation outputs corresponding to a first subset of said set of binary sequences available to said transmitting node, and a next-largest sum of correlation outputs corresponding to a second subset of said set of binary sequences available to said transmitting node; (ii) means for forming a ratio of said largest sum to said next-largest sum; and (iii) means for evaluating said ratio to determine whether said ratio is greater than a predetermined threshold. - View Dependent Claims (2, 3, 4)
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5. A method for analyzing a signal received at a receiving node of a multi-node communication network in order to determine a particular subset of binary spreading-code sequences most likely to have been transmitted by a specified transmitting node of said network, said particular subset being contained in a multi-member set of binary spreading-code sequences available to said specified transmitting node, said specified transmitting node having actually transmitted a certain subset of binary spreading-code sequences selected from said set of binary spreading-code sequences available to said specified transmitting node, said particular subset thereby being determined with a high degree of probability to be the certain subset that was actually transmitted, said method comprising:
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a) correlating each binary spreading-code sequence in said set of binary spreading-code sequences available to said specified transmitting node with said received signal to produce a set of correlation outputs, each correlation output corresponding to a specified one of said binary spreading-code sequences available to said specified transmitting node; and b) evaluating said set of correlation outputs by; (i) computing a largest sum of correlation outputs corresponding to a first subset of said set of binary spreading-code sequences available to said specified transmitting node, and a next-largest sum of correlation outputs corresponding to a second subset of said set of binary spreading-code sequences available to said specified transmitting node; (ii) forming a ratio of said largest sum to said next-largest sum; and (iii) evaluating said ratio to determine whether said ratio is greater than a first predetermined threshold; to identify said particular subset of said set of available binary spreading-code sequences as being most likely to have been transmitted by said specified transmitting node. - View Dependent Claims (6, 7, 8)
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Specification