Packet modulation for DSL
First Claim
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1. A method of reducing cross talk communication over twisted-pair telephone lines between a central office and a subscriber by a plurality of transceivers comprising the steps of:
- determining at least one crosstalk reduction factor at the central office;
calculating a duty cycle in response to the reduction factor; and
conveying a duty cycle to all transceivers in a cable bundle.
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Abstract
The subject invention defines the details of packet based DSL modulation. The invention claims a method for minimizing crosstalk generation by specifying a duty cycle for bursted carrier data traffic and a method of providing opportunistic echo canceller training. In this way the present invention minimizes power and interference while maximizing the peak capacity of a transceiver used in ADSL communication systems.
30 Citations
6 Claims
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1. A method of reducing cross talk communication over twisted-pair telephone lines between a central office and a subscriber by a plurality of transceivers comprising the steps of:
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determining at least one crosstalk reduction factor at the central office;
calculating a duty cycle in response to the reduction factor; and
conveying a duty cycle to all transceivers in a cable bundle.
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2. A method of reducing cross talk communication over twisted-pair telephone lines between a central office and a subscriber by a plurality of transceivers comprising the steps of:
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determining a plurality of crosstalk reduction factors at the central office;
calculating duty cycles in response to each reduction factor; and
conveying each duty cycle to individual transceivers in a cable bundle based on a level of service selected by the subscriber. - View Dependent Claims (3, 4, 5, 6)
transmitting a multi-carrier data signal in burst mode;
operating transceivers in half-duplex mode;
training an echo canceller while in half duplex mode;
transmitting in full-duplex mode thereafter.
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4. A method of reducing cross talk communication over twisted-pair telephone lines between a central office and a subscriber by a plurality of transceivers in accordance with claim 3 wherein there is no data throughput during half-duplex periods.
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5. A method of reducing cross talk communication over twisted-pair telephone lines between a central office and a subscriber by a plurality of transceivers in accordance with claim 3 wherein the echo canceller is trained whenever there is no collision between transmitters and if a collision is detected, the training is skipped.
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6. A method of reducing cross talk communication over twisted-pair telephone lines between a central office and a subscriber by a plurality of transceivers in accordance with claim 5 wherein collisions include errored data packets.
Specification