Estimation of DSL telephone loop capability using CAZAC sequence
AssigneeIntel Corporation
InventorsWesley H. Smith, Veda Krishnan, Xiao M. Gao, Kanna Krishnan
Life of this patent
Estimating the term…
Abstract
A system for determining whether a telephone loop is capable of carrying a Digital Subscriber Line (DSL) signal. A Constant Amplitude Zero Auto Correlation (CAZAC) sequence signal is generated and transmitted through the loop plant to a central office and the received echo signal is processed using second-order statistics. The second-order statistics calculation permits determination of the echo signal amplitude and time between the echo signal and sequence signal. The echo signal amplitude and time may be used to obtain telephone loop characteristics such as loop length.
Claims26
A method, comprising:
- determining second-order statistics of an echo signal from a first signal of a first length;
- and
- ascertaining if the echo signal can be detected from the second-order statistics, and, if so, determining a length of a loop plant communicating the first signal from the echo signal.
A system, comprising:
- a sequencer to form a Constant Amplitude Zero Auto Correlation sequence signal;
- and
- a controller coupled to said sequencer, said controller to determine a length of the Constant Amplitude Zero Auto Correlation sequence signal to permit detection of a Constant Amplitude Zero Auto Correlation sequence signal echo, said controller to determine a length of a loop plant from the sequence signal echo.
An article comprising a storage medium storing instructions readable by a processor-based system that, if executed, enables the processor-based system to:
- generate a first signal of a first length;
- transmit the first signal to a loop plant;
- determine second-order statistics of an echo signal from the first signal, wherein a length of the loop plant is obtained from the echo signal;
- ascertain if the echo signal can be detected from the second-order statistics;
- generate a second signal of a second length that is greater than the first length if the echo signal cannot be detected from the second-order statistics;
- and
- wherein generation of the first signal, transmission, determination, and generation of the second signal is to occur until the echo signal is detected.
A method comprising:
- generating a first signal of a first length;
- transmitting the first signal to a loop plant;
- determining second-order statistics of an echo signal from the first signal;
- ascertaining if the echo signal can be detected from the second-order statistics, wherein a length of the loop plant is obtained from the echo signal;
- generating a second signal of a second length that is greater than the first length if the echo signal cannot be detected from the second-order statistics;
- and
- wherein generating the second signal, transmitting the second signal and determining second-order statistics of an echo signal from the second signal occurs until the echo signal is detected.
Dependencies are inferred from the claim text.