Simultaneous voice and data modem
First Claim
Patent Images
1. A modem for simultaneous communication of voice and data comprising:
- a voice input circuit for receiving digital samples of voice content;
a data input circuit for receiving digital data for transmission;
a modulator for modulating a predetermined audio frequency carrier with the received digital data to form a modulated data signal; and
a digital signal processing module for combining the voice content and the modulated data signal together for simultaneous transmission over a single voice communication channel by reducing the frequency spectrum of the voice content to frequencies below approximately a first frequency cutoff value selected so as to substantially preserve the voice content, and whereinthe modulated data signal is limited in frequency spectrum to frequencies above approximately the first frequency cutoff value so as to minimize interference with the voice content.
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Abstract
Simultaneous transmission of voice and data over the voice channel of a wireless communications network, such as a “cell phone” network, is reconfigurable on the fly among multiple operating modes, including a lull detection mode in which data is transferred during a lull or quiet period in the voice content. Additionally, control signaling in the voice channel, rather than over a separate control or “overhead” channel is employed to support SVD. The described system operates transparently over any wireless telecommunications system.
99 Citations
36 Claims
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1. A modem for simultaneous communication of voice and data comprising:
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a voice input circuit for receiving digital samples of voice content; a data input circuit for receiving digital data for transmission; a modulator for modulating a predetermined audio frequency carrier with the received digital data to form a modulated data signal; and a digital signal processing module for combining the voice content and the modulated data signal together for simultaneous transmission over a single voice communication channel by reducing the frequency spectrum of the voice content to frequencies below approximately a first frequency cutoff value selected so as to substantially preserve the voice content, and wherein the modulated data signal is limited in frequency spectrum to frequencies above approximately the first frequency cutoff value so as to minimize interference with the voice content. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of simultaneous transmission of voice content and data over a single voice channel of a wireless telecommunications system, the voice channel being established between first and second stations, and the method comprising the steps of:
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transmitting voice content from the first station to the second station over the voice channel; while transmitting voice content, monitoring the voice content to detect a lull; responsive to detecting a lull in the voice content, reducing the frequency spectrum of the transmitted voice content and continuing to transmit voice content; and also responsive to said detecting a lull in the voice content, commencing simultaneous transmission of data over the voice channel. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method of simultaneous transmission of voice content and data over a single voice channel of a wireless telecommunications system, the voice channel being established between first and second stations, and the method comprising the steps of:
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transmitting voice content from the first station to the second station over the voice channel; while transmitting voice content, monitoring the voice content to detect a lull; responsive to detecting a lull in the voice content, reducing the frequency spectrum of the transmitted voice content and continuing to transmit voice content; and also responsive to said detecting a lull in the voice content, commencing simultaneous transmission of data over the voice channel;
whereinsaid transmitting voice content from the first station includes limiting a frequency spectrum of the transmitted voice content by filtering the voice content by means of a first low-pass filter prior to transmission; and said reducing the frequency spectrum of the transmitted voice content includes filtering the voice content prior to transmission by means of a second low-pass filter in lieu of the first low-pass filter, the second LPF having a lower cutoff frequency than the first LPF. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A method of simultaneous transmission of voice content and data over a single voice channel of a wireless telecommunications system, the voice channel being established between first and second stations, and the method comprising the steps of:
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partitioning the voice channel so as to comprise three bands, namely a voice band, a data band and a control band, all within the audio range of frequencies; transmitting voice content from the first station to the second station over the voice band of the voice channel; while transmitting voice content, monitoring the voice content to detect a lull; and responsive to detecting a lull in the voice content, transmitting data over the data band of the voice channel while continuing to simultaneously transmit voice content over the voice band of the voice channel. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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29. A method of simultaneous transmission of voice content and data over a single voice channel of a wireless telecommunications system, the voice channel being established between first and second stations, and the method comprising the steps of:
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partitioning the voice channel so as to comprise three bands, namely a voice band, a data band and a control band, all within the audio range of frequencies; transmitting voice content from the first station to the second station over the voice band of the voice channel; while transmitting voice content, monitoring the voice content to detect a lull; and responsive to detecting a lull in the voice content, transmitting data over the data band of the voice channel while continuing to simultaneously transmit voice content over the voice band of the voice channel; and wherein said transmitting voice content includes limiting the voice spectrum to frequencies below a predetermined maximum frequency so as to allow data transmission over the voice channel using frequencies greater than the voice spectrum maximum frequency.
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30. A method of simultaneous transmission of voice content and data over a single voice channel of a wireless telecommunications system, the voice channel being established between first and second stations, and the method comprising the steps of:
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band limiting the voice content to frequencies up to approximately a first predetermined audio frequency while data is not being transmitted; while transmitting voice content, monitoring the voice content to detect a lull; responsive to detecting a lull in the voice content, further band limiting the voice content to frequencies up to approximately a second predetermined audio frequency, the second frequency being lower than the first frequency, thereby reducing the voice spectrum of the transmitted signal while data also is being transmitted; and also responsive to said detecting a lull in the voice content, commencing simultaneous transmission of data over the voice channel. - View Dependent Claims (31, 32, 33, 34, 35, 36)
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Specification