Detection
AssigneeInfineon Technologies AG
InventorMichael Lewis
Life of this patent
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Abstract
In a method and apparatus for detecting a message in a signal the message begins with a preamble consisting of a fixed sequence of symbols, each having a symbol time T, modulated by repetitions of a higher rate code having low autocorrelation at lags anything other than zero. The repetitive code and the fixed sequence of symbols is known at the detector. The method comprises correlating the signal with the repetitive code; autocorrelating the signal with a copy of the signal, which is delayed substantially a symbol time; correlating the signal with the preamble; and indicating the detection of a message if a value in the signal is greater than a threshold value.
Claims16
A method for detecting a message in a signal, wherein said message begins with a preamble consisting of a fixed sequence of symbols, each having a symbol time T, modulated by repetitions of a higher rate code having low autocorrelation at lags anything other than zero, wherein said repetitive code and said fixed sequence of symbols are known at said detector, comprising the steps of:
- receiving said signal as a first signal,
- correlating said first signal with said repetitive code to form a second signal,
- autocorrelating said second signal with a copy of said second signal which is delayed substantially a symbol time to form a third signal,
- correlating said third signal with said preamble to form a fourth signal, and
- indicating the detection of a message if a value in said fourth signal is greater than a threshold value.
An apparatus for detecting a message in a signal, wherein said message begins with a preamble consisting of a fixed sequence of symbols, each having a symbol time T, modulated by repetitions of a higher rate code having low autocorrelation at lags anything other than zero, wherein said repetitive code is known at said detector and said fixed sequence of symbols is known at said detector, comprising
- a first correlater to be arranged to correlate said signal with said repetitive code,
- an autocorrelator to be arranged to autocorrelate said signal with a copy of said signal, which is delayed substantially a symbol time,
- a second correlator to be arranged to correlate said signal with said preamble, and wherein
- said apparatus is arranged to indicate the detection of a message if a value in said signal is greater than a threshold value.
Dependencies are inferred from the claim text.