Echo device method for locating upstream ingress noise gaps at cable television head ends
First Claim
1. A method of testing the reliability of an upstream data path in a cable system using a cable modem device configured for use in a variable carrier frequency loop testing system, the method comprising:
- receiving a downstream test packet at a demodulator in a cable modem device, the test packet having a first media access control address of the cable modem device;
replacing the first media access control address with a second media access control address corresponding to a test packet checker device; and
transmitting the test packet upstream to the test packet checker.
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Accused Products
Abstract
A system and method for locating ingress noise gaps for an upstream data carrier in a cable network utilizing cable modems is described. A system for identifying a transmission frequency that has less noise than other available frequency bands includes a packet generator, a rate controller, an echo device, a demodulator, and a packet checker. The packet generator and rate controller, contained in a cable modem termination system, send test data downstream to the echo device which then redirects the test data upstream at a selected test frequency. The echo device, which may be located within the cable modem termination system or outside the termination system, listens on the downstream path for data packets addressed to it. Once received, the echo changes the address of the test data to the address of the packet checker. The packet checker then receives and analyzes the test data packet sent from the echo device to assess the amount of noise on that particular test frequency. The echo device can be a subscriber cable data modem configured to receive test packets sent downstream or a custom-built device located anywhere on the downstream path or within the cable modem termination system.
133 Citations
21 Claims
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1. A method of testing the reliability of an upstream data path in a cable system using a cable modem device configured for use in a variable carrier frequency loop testing system, the method comprising:
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receiving a downstream test packet at a demodulator in a cable modem device, the test packet having a first media access control address of the cable modem device; replacing the first media access control address with a second media access control address corresponding to a test packet checker device; and transmitting the test packet upstream to the test packet checker. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for identifying a transmission frequency for transmitting digital data upstream in a cable system, said transmission frequency having relatively less noise than at least some other frequency bands, the system comprising:
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a packet generator for generating one or more test packets at a selected frequency and transmitting a test packet to an echo device located downstream on the cable system; a packet checker for receiving the test packets sent by the echo device at the selected frequency, wherein the packet checker assists the system in determining the transmission frequency for transmitting digital data upstream by evaluating the test packets to determine a noise level. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification