Method for improved cable modem ranging in a data-over-cable system
First Claim
1. In a data-over-cable system, a method for estimating an initial transmit level for a cable modem to range on an upstream channel, the upstream channel carrying data transmissions from a plurality of cable modems to a cable modem termination system at a head-end of a cable network, the method comprising the steps of:
- ascertaining a characteristic value for the data-over-cable system, wherein the characteristic value is associated with configuration parameters for the data-over-cable system;
measuring a signal level of a downstream channel at the cable modem, wherein the downstream channel carries signals from the head-end to the plurality of cable modems; and
setting the initial transmit level to a difference between the characteristic value and the signal level of the downstream channel,whereby the cable modem begins ranging at the initial transmit level and is recognized by the cable modem termination system with fewer attempts than if the cable modem began ranging at a minimum specified transmit level.
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Accused Products
Abstract
Methods for improved cable modem ranging in a data-over-cable system. One method includes receiving a value that characterizes how equipment in the network is configured. Using this characteristic value, a cable modem may estimate loss in its upstream path from a measurement of a downstream signal and thereby estimate its initial transmit level during ranging. Launching at a proper initial transmit level may ensure that range request messages arrive at the cable modem termination system with sufficient strength to be detected and hence ameliorate ranging. Another method collects difference between these estimated initial transmit levels and the final transmit levels that succeeded in evoking a response from the cable modem termination system. The collected differences are analyzed and the result of the analysis is passed to cable modems to adjust their estimated initial transmit levels. These methods may shorten a cable modem'"'"'s time for ranging and may decrease collisions on the upstream path when many cable modems try to range simultaneously.
260 Citations
32 Claims
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1. In a data-over-cable system, a method for estimating an initial transmit level for a cable modem to range on an upstream channel, the upstream channel carrying data transmissions from a plurality of cable modems to a cable modem termination system at a head-end of a cable network, the method comprising the steps of:
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ascertaining a characteristic value for the data-over-cable system, wherein the characteristic value is associated with configuration parameters for the data-over-cable system; measuring a signal level of a downstream channel at the cable modem, wherein the downstream channel carries signals from the head-end to the plurality of cable modems; and setting the initial transmit level to a difference between the characteristic value and the signal level of the downstream channel, whereby the cable modem begins ranging at the initial transmit level and is recognized by the cable modem termination system with fewer attempts than if the cable modem began ranging at a minimum specified transmit level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. In a data-over-cable system, a method for adjusting an initial transmit level for a cable modem to range on an upstream channel, the upstream channel carrying data transmissions from a plurality of cable modems to a cable modem termination system at a head-end of a cable network, the method comprising the steps of:
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receiving an implementation delta value on the cable modem in a message from the cable modem termination system, wherein the implementation delta value represents a dynamical correction to the initial transmit level that is responsive to changes in the data-over-cable network; and adjusting the initial transmit level by adding the implementation delta value, whereby the cable modem begins ranging at the adjusted initial transmit level and is recognized by the cable modem termination system with fewer attempts than if the cable modem began ranging at a minimum specified transmit level. - View Dependent Claims (11, 12, 13, 14, 15)
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16. In a data-over-cable system, a method for improving ranging of a plurality of cable modems on an upstream channel, the upstream channel carrying data transmissions from the plurality of cable modems to a cable modem termination system at a head-end of a cable network, the method comprising the step of:
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sending configuration information in a message from the cable modem termination system to the plurality of cable modems, wherein the configuration information is combined with a signal level for downstream transmissions as measured by a cable modem to provide an estimate for an initial transmit level for the cable modem during ranging, whereby the cable modem begins ranging at the initial transmit level and is recognized by the cable modem termination system with fewer attempts than if the cable modem began ranging at a minimum specified transmit level. - View Dependent Claims (17, 18, 19, 20)
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21. In a data-over-cable system, a method for improving ranging of a plurality of cable modems on an upstream channel, the upstream channel carrying data transmissions from the plurality of cable modems to a cable modem termination system at a head-end of a cable network, the method comprising the steps of:
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ascertaining an implementation delta value on the cable modem termination system from difference values provided by the plurality of cable modems; and sending the implementation delta value in a message from the cable modem termination system to the plurality of cable modems, wherein the implementation delta value is combined with an initial transmit level for the cable modem during ranging to adjust the initial transmit level, whereby the cable modem begins ranging at the adjusted initial transmit level and is recognized by the cable modem termination system with fewer attempts than if the cable modem began ranging at a minimum specified transmit level. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. In a data-over-cable system, a method for estimating an initial transmit level for a cable modem to range on an upstream channel, the upstream channel carrying data transmissions from a plurality of cable modems to a cable modem termination system at a head-end of a cable network, the method comprising the steps of:
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receiving an Upstream Channel Descriptor message on the cable modem from the cable modem termination system, wherein the message contains a characteristic value associated with configuration parameters for the data-over-cable system; measuring a signal level of a downstream channel on the cable modem, wherein the downstream channel carries signals from the head-end to the plurality of cable modems; setting the initial transmit level to a difference between the characteristic value and the signal level of the downstream channel; receiving an implementation delta value on the cable modem in a Bandwidth Allocation MAP message from the cable modem termination system, wherein the implementation delta value represents a dynamical correction to the initial transmit level that is responsive to changes in the data-over-cable network; and adjusting the initial transmit level by adding the implementation delta value, whereby the cable modem begins ranging at the adjusted initial transmit level and is recognized by the cable modem termination system with fewer attempts than if the cable modem began ranging at a minimum specified transmit level. - View Dependent Claims (29)
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30. In a data-over-cable system, a method for improving ranging of a plurality of cable modems on an upstream channel, the upstream channel carrying data transmissions from the plurality of cable modems to a cable modem termination system at a head-end of a cable network, the method comprising the step of:
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sending a characteristic value in an Upstream Channel Descriptor message from the cable modem termination system to the plurality of cable modems, wherein the characteristic value is combined with a signal level for downstream transmissions as measured by a cable modem to provide an estimate for an initial transmit level for the cable modem during ranging; receiving difference values on the cable modem termination system from Management Information Bases in the plurality of cable modems; calculating an implementation delta value from the difference values; and sending the implementation delta value in a Bandwidth Allocation MAP message from the cable modem termination system to a cable modem, wherein the implementation delta value is combined with an initial transmit level for the cable modem during ranging to adjust the initial transmit level, whereby the cable modem begins ranging at the adjusted initial transmit level and is recognized by the cable modem termination system with fewer attempts than if the cable modem began ranging at a minimum specified transmit level. - View Dependent Claims (31, 32)
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Specification