Communication mode identification technique
First Claim
1. Apparatus for use in a communications system utilizing first and second modes wherein in said first mode information represented by symbols in a signal constellation is transmitted and in said second mode said information is not transmitted, said apparatus comprisingmeans for receiving data;
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for generating at least one second symbol representative of a selected one of said first and second modes, said second symbol being in a second portion of said signal constellation, and said second symbol not being used to represent said received data.
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Accused Products
Abstract
A technique for use in communications systems utilizing busy and idle modes. In the busy mode, symbols representative of data are transmitted to system end users. In the idle mode, during which no data is communicated to end users, idle mode symbols are transmitted. Such idle mode symbols are not used to represent data and are only transmitted during the idle mode. Advantageously, such idle mode symbols maintain adaptive apparatus, such as AGC circuits, NEXT cancellers and equalizers, in their properly converged state. In the disclosed embodiment, the idle mode symbols are the innermost symbols in a signal constellation and transition from the idle to busy mode is represented by the transmission of a predetermined number of outermost symbols in the signal constellation. Use of such symbols for idle-to-busy mode transitions advantageously provides ready detection of such transitions. In addition, use of the innermost symbols for the idle mode reduces spectral emission and crosstalk.
39 Citations
18 Claims
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1. Apparatus for use in a communications system utilizing first and second modes wherein in said first mode information represented by symbols in a signal constellation is transmitted and in said second mode said information is not transmitted, said apparatus comprising
means for receiving data; - and
means responsive to data received by the means for receiving data and a control signal for generating first symbols representative of said received data, said first symbols being in a first portion of said signal constellation; and
for generating at least one second symbol representative of a selected one of said first and second modes, said second symbol being in a second portion of said signal constellation, and said second symbol not being used to represent said received data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for use in a communications system utilizing first and second modes, said apparatus comprising
means for receiving first symbols and at least one second symbol from said communications channel, said first and second symbols lying in a signal constellation and said second symbol being different from any of said first symbols; - and
means responsive to the received first and second symbols for decoding said first symbols into an associated plurality of bits and for detecting a selected one of said first and second modes in response to said second symbol; wherein, in said first mode, information represented by symbols in the signal constellation is transmitted and in said second mode said information is not transmitted. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for use in a communications system utilizing first and second modes wherein, in said first mode, information represented by symbols in a signal constellation is transmitted and in said second mode said information is not transmitted, said method comprising the steps of
receiving data; -
generating first symbols representative of said received data in response to a control signal, said first symbols being in a first portion of said signal constellation; and generating at least one second symbol representative of a selected one of said first and second modes, said second symbol being in a second portion of said signal constellation, and said second symbol not being used to represent said data.
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18. A method for use in a communications system utilizing first and second modes, said method comprising the steps of
receiving first symbols and at least one second symbol from said communications channel, said first and second symbols lying in a signal constellation and said second symbol being different from any of said first symbols; -
decoding said first symbols into an associated plurality of bits; and detecting a selected one of said first and second symbol; wherein, in said first mode, information represented by symbols in the signal constellation is transmitted and in said second mode said information is not transmitted.
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Specification