SYSTEM AND METHOD FOR OBTAINING A MESSAGE TYPE IDENTIFIER THROUGH AN IN-BAND MODEM
First Claim
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1. A method of obtaining a message type identifier embedded in a vocoder packet comprising:
- receiving and decoding the vocoder packet;
filtering the decoded vocoder packet until a synchronization signal is detected, the filtering comprising correlating the decoded vocoder packet with a predetermined sequence to generate the synchronization signal;
determining the polarity of the synchronization signal; and
deriving the message type identifier based on the polarity of the detected synchronization signal,wherein a first polarity identifies a first message type, andwherein a second polarity identifies a second message type.
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Abstract
A system and method is provided for obtaining a message type identifier through a speech codec (in-band) such as found in a wireless communication network. A first predetermined sequence with noise-like characteristics is detected and identifies a first message type. A second predetermined sequence with noise-like characteristics is detected and identifies a second message type.
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Citations
22 Claims
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1. A method of obtaining a message type identifier embedded in a vocoder packet comprising:
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receiving and decoding the vocoder packet; filtering the decoded vocoder packet until a synchronization signal is detected, the filtering comprising correlating the decoded vocoder packet with a predetermined sequence to generate the synchronization signal; determining the polarity of the synchronization signal; and deriving the message type identifier based on the polarity of the detected synchronization signal, wherein a first polarity identifies a first message type, and wherein a second polarity identifies a second message type. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A memory storing a computer program that, when executed, causes a computer to perform the acts of:
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receiving and decoding a vocoder packet; filtering the decoded vocoder packet until a synchronization signal is detected, the filtering comprising correlating the decoded vocoder packet with a predetermined sequence to generate the synchronization signal; determining the polarity of the synchronization signal; and deriving a message type identifier based on the polarity of the detected synchronization signal, wherein a first polarity identifies a first message type, and wherein a second polarity identifies a second message type.
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9. An apparatus comprising:
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a receiver configured to receive and decode a vocoder packet; a filter configured to filter the decoded vocoder packet until a synchronization signal is detected, the filter comprising a correlator to correlate the decoded vocoder packet with a predetermined sequence to generate the synchronization signal; and a processor configured to determine the polarity of the synchronization signal and derive a message type identifier based on the polarity of the detected synchronization signal, wherein a first polarity identifies a first message type, and wherein a second polarity identifies a second message type. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. An apparatus comprising:
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means for receiving and decoding a vocoder packet; means for filtering the decoded vocoder packet until a synchronization signal is detected, the filtering comprising correlating the decoded vocoder packet with a predetermined sequence to generate the synchronization signal; means for determining the polarity of the synchronization signal; and means for deriving the message type identifier based on the polarity of the detected synchronization signal, wherein a first polarity identifies a first message type, and wherein a second polarity identifies a second message type. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification