Echo device method for locating upstream ingress noise gaps at cable television head ends
First Claim
1. 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:
- a packet generator capable of generating a test packet;
a rate controller for controlling a packet generation rate of the packet generator such that a downstream packet rate does not exceed the packet rate capacity of the upstream path;
an echo device capable of receiving the test packet sent downstream and redirecting it upstream at a selected test frequency;
a demodulator which can receive the test packet sent upstream at the test frequency; and
a packet checker which can receive and analyze the test packet sent upstream to assess the amount of noise on the test frequency.
2 Assignments
0 Petitions
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 recieves 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.
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Citations
30 Claims
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1. 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 capable of generating a test packet; a rate controller for controlling a packet generation rate of the packet generator such that a downstream packet rate does not exceed the packet rate capacity of the upstream path; an echo device capable of receiving the test packet sent downstream and redirecting it upstream at a selected test frequency; a demodulator which can receive the test packet sent upstream at the test frequency; and a packet checker which can receive and analyze the test packet sent upstream to assess the amount of noise on the test frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A cable modem device configured for use in a variable carrier frequency loop testing system, the device comprising:
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a demodulator for receiving and forwarding a downstream test packet wherein the test packet has a media access control address of the cable modem device; an address manipulation device which replaces the media access control address of the cable modem device with a media access control address of a test packet checker device without modifying any other portion of the test packet; and a modulator for transmitting the test packet upstream to the test packet checker.
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19. A method of 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 method comprising:
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(a) selecting a test frequency; (b) transmitting test data at a downstream frequency, the test data being addressed to an echo device located downstream on the cable system; (c) receiving test data sent by said echo device at the test frequency; (d) determining a noise level associated with the test frequency by evaluating the received test data; and (e) repeating steps (a) through (d) for a plurality of test frequencies to identify the transmission frequency. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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27. A method of identifying a frequency channel for transmitting digital data upstream in a cable system, the method comprising:
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(a) selecting a test frequency; (b) generating a test data stream containing a plurality of bits; (c) transmitting said test data stream from a second point on the cable system downstream to a first point on the cable system; (d) receiving said test data stream at the second point located upstream from said first point on the cable system; (e) evaluating the condition of said test data stream at said second point to assess a noise level at said selected frequency; (f) repeating steps (b) through (e) for a plurality of test frequencies; and (g) determining which of said plurality of test frequencies contains the least noise. - View Dependent Claims (28, 29, 30)
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Specification