Detecting modem power state change
AssigneeBritish Telecommunications public limited company
InventorsFeiyu Fang, Lykourgos Kekempanos, Daniel Gilks
Life of this patent
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Abstract
A method of determining when there has been a change in the modem power state of a modem connected to a digital subscriber line. An Uncalibrated Echo Response (UER) trace is obtained from the digital subscriber line by running a Single Ended Line Test (SELT) on the line. This UER trace is compared to a historical (baseline) UER trace from the same line. A difference in the two traces in a higher frequency range (for example, DS3 for a VDSL line), is indicative of a possible modem power state change.
Claims8
A method of detecting a modem power state change, wherein the modem is connected to a digital subscriber line, said method comprising:
- generating a test echo response from the digital subscriber line using a single ended line test, wherein said test echo response comprises a frequency domain trace;
- retrieving a historical echo response associated with the digital subscriber line, wherein the historical echo response comprises a frequency domain trace from the digital subscriber line taken previously;
- calculating the difference between the test echo response and the historical echo response over a higher frequency band;
- and
- determining if a modem power state change has occurred in dependence on the result of the calculated difference.
A test module for of detecting a modem power state change, wherein the modem is connected to a digital subscriber line, and said test module is adapted in operation to:
- generate a test echo response from the digital subscriber line using a single ended line test, wherein said test echo response comprises a frequency domain trace;
- retrieve a historical echo response associated with the digital subscriber line, wherein the historical echo response comprises a frequency domain trace from the digital subscriber line taken previously;
- calculate the difference between the test echo response and the historical echo response over a higher frequency band;
- and
- determine if a modem power state change has occurred in dependence on the result of the calculated difference.
Dependencies are inferred from the claim text.