DMT system with variable subchannel spacing in TCM ISDN noise
AssigneeTexas Instruments Incorporated
InventorArthur J. Redfern
Life of this patent
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Abstract
A device comprises a first component operable to produce a plurality of discrete multitone symbols based in part on a subchannel spacing and a cyclic extension length and a second component operable to determine the subchannel spacing and the cyclic extension length, the cyclic extension length selected based on the subchannel spacing to increase the number of discrete multitone symbols transmitted during a low noise interval of a cyclostationary noise environment.
Claims20
A device, comprising:
- a first component operable to produce a plurality of discrete multitone symbols based in part on a subchannel spacing and a cyclic extension length;
- and
- a second component operable to determine the subchannel spacing and the cyclic extension length, the cyclic extension length selected based on the subchannel spacing to increase the number of discrete multitone symbols transmitted during a low noise interval of a cyclostationary noise environment.
A method of communicating in a cyclostationary noise environment, comprising:
- transmitting one or more first discrete multitone symbols during a high noise interval;
- transmitting one or more second discrete multitone symbols during a low noise interval, the first and second discrete multitone symbols having a cyclic extension length selected based on a subchannel spacing to increase the number of second discrete multitone symbols transmitted.
The method of 12, wherein the first discrete multitone symbols are encoded based on a first subchannels bit count and the second discrete multitone symbols are encoded based on a second subchannels bit count.
The method of 12, further including:
- selecting an encoding mode, the encoding mode having a single subchannels bit count mode according to which the first discrete multitone symbols and the second discrete multitone symbols are encoded based on a first subchannels bit count and a dual subchannels bit count mode according to which the first discrete multitone symbols are encoded based on the first subchannels bit count and the second discrete multitone symbols are encoded based on a second subchannels bit count.
The method of 12, wherein a period of the cyclostationary noise environment and the discrete multitone encoding is a hyperframe and the method further includes:
- transmitting by a first transceiver a known bit pattern on at least some of the subchannels of the initial discrete multitone symbol of a hyperframe;
- receiving by a second transceiver the initial discrete multitone symbol of a hyperframe;
- and
- determining by the second transceiver, based on the known bit pattern contained in the at least some of the subchannels of the initial discrete multitone symbol of the hyperframe, the hyperframe alignment known to the first transceiver.
A digital subscriber line communication system, comprising:
- a first transceiver;
- and
- a second transceiver operable to transmit a plurality of discrete multitone symbols to the first transceiver, the discrete multitone symbols based in part on a subchannel spacing and a cyclic extension length, the cyclic extension length selected based on the subchannel spacing to increase the number of discrete multitone symbols transmitted during an interval of low noise at the first transceiver in a cyclostationary noise environment.
Dependencies are inferred from the claim text.