Detection of double talk in telecommunications networks

Patent metadata

Field	Value
Publication number	US-9407320-B2
Application number	US-201514853979-A
Country	US
Kind code	B2
Filing date	Sep 14, 2015
Priority date	May 9, 2008
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

In one embodiment, the presence of double talk (DT) is detected in a telecommunications network having a near-end user and a far-end user. The energies of both (1) a signal received from the far-end user by the near-end user and (2) a signal to be communicated from the near-end user to the far-end user are computed. An echo return loss (ERL) estimate is calculated based on the energy calculations, and a preliminary decision is made as to whether DT is present based on the ERL estimate and the energy calculations. If DT is detected, then a counter is set to a hangover value. If DT is not detected, then the counter is reduced. This process is repeated, and, for each iteration, a final decision as to whether DT is present is made based on the counter value.

First claim

The invention claimed is:

1. One or more non-transitory machine-readable storage media comprising a plurality of instructions stored thereon that, when executed, cause a controller to:
generate a measure of average energy of a near-end signal in a telecommunications network;
generate a measure of average energy of a far-end signal in the telecommunications network;
generate a double-talk (DT) decision statistic based on the near-end average energy measure and the far-end average energy measure, wherein to generate the DT decision statistic comprises to (i) generate an estimate of echo return loss (ERL) based on the near-end average energy measure and the far-end average energy measure and (ii) generate the DT decision statistic based on the ERL estimate, the near-end average energy measure, and the far-end average energy measure; and
generate a DT decision as to whether or not double talk is present in the telecommunications network based on the DT decision statistic.

2. The one or more non-transitory machine-readable storage media of claim 1 , wherein to generate the measure of average energy of the near-end signal in the telecommunications network comprises to generate a weighted moving average of instantaneous near-end energy measures, and
wherein to generate the measure of average energy of the far-end signal in the telecommunications network comprises to generate a weighted moving average of instantaneous far-end energy measures.

3. The one or more non-transitory machine-readable storage media of claim 1 , wherein:
to generate the measure of average energy of the near-end signal comprises to generate a measure of average energy of the near-end signal of the telecommunications network at a first rate to generate a plurality of near-end energy measures;
to generate the measure of average energy of the far-end signal comprises to generate a measure of average energy of the far-end signal in the telecommunications network at the first rate to generate a plurality of far-end energy measures;
to generate the DT decision statistic comprises to generate the DT decision statistic at a rate lower than the first rate to generate a plurality of ERL estimates; and
to generate the DT decision comprises to generate the DT decision at the rate lower than the first rate to generate a plurality of DT decisions.

4. The one or more non-transitory machine-readable storage media of claim 1 , wherein to generate the estimate of ERL comprises to generate the estimate of ERL as a weighted moving average of instantaneous ERL estimates, wherein each instantaneous ERL estimate is a ratio of the near-end average energy measure and the far-end average energy measure.

5. The one or more non-transitory machine-readable storage media of claim 1 , wherein an echo path delay exists between receipt of the far-end signal and occurrence of corresponding echo in the near-end signal, and
wherein to generate the measure of average energy of at least one of (i) the near-end signal or (ii) the far-end signal comprises to generate the measure of average energy of the at least one of the near-end signal or the far end-signal based on the echo path delay.

6. The one or more non-transitory machine-readable storage media of claim 1 , wherein to generate the estimate of ERL comprises to:
generate a ratio of the near-end average energy measure and the far-end average energy measure;
compare the ratio to at least one boundary; and
determine whether or not to inhibit updating of the ERL estimate based on the comparison of the ratio to the at least one boundary.

7. The one or more non-transitory machine-readable storage media of claim 6 , wherein to:
compare the ratio to the at least one boundary comprises to compare the ratio to an upper boundary and a lower boundary;
determine whether or not to inhibit updating of the ERL estimate comprises to determine to inhibit the updating of the ERL estimate if the ratio falls outside of the upper and lower boundaries.

8. The one or more non-transitory machine-readable storage media of claim 1 , wherein the plurality of instructions further cause the controller to determine whether or not to inhibit updating of a set of filter coefficients based on the DT decision, wherein the filter coefficients are used by the telecommunications network to filter the far-end signal to generate an estimate of echo in the near-end signal.

9. The one or more non-transitory machine-readable storage media of claim 1 , wherein the near-end average energy measure comprises a measure of energy of a near-end signal before the near-end signal is subject to echo cancellation; and
wherein to generate the estimate of ERL comprises to generate an estimate of ERL based on (i) the measure of energy of the near-end signal before the near-end signal is subject to echo cancellation and (ii) the far-end average energy measure.

10. The one or more non-transitory machine-readable storage media of claim 1 , wherein to generate the DT decision statistic comprises to compute the DT decision statistic as a function of the ERL estimate, the near-end average energy measure, and the far-end average energy measure.

11. The one or more non-transitory machine-readable storage media of claim 1 , wherein to generate the DT decision comprises to (i) compare the DT decision statistic to a threshold and generate the DT decision based on the comparison.

12. One or more non-transitory machine-readable storage media comprising a plurality of instructions stored thereon that, when executed, cause a controller to:
generate a measure of average energy of a near-end signal in a telecommunications network;
generate a measure of average energy of a far-end signal in the telecommunications network;
generate a double-talk (DT) decision statistic based on the near-end average energy measure and the far-end average energy measure, wherein to generate the DT decision statistic comprises to (i) generate an estimate of echo return loss (ERL) based on the near-end average energy measure and the far-end average energy measure and (ii) generate the DT decision statistic based on ERL estimate, the near-end average energy measure, and the far-end average energy measure;
generate a DT decision as to whether or not double talk is present in the telecommunications network based on the DT decision statistic;
determine whether or not to inhibit updating a set of filter coefficients based on the DT decision, wherein the filter coefficients are used by the telecommunications network to filter the far-end signal to generate an estimate of echo in the near-end signal and wherein to determine whether or not to inhibit updating the set of filter coefficients comprises to:
set a counter to a specified hangover value if the DT decision indicates that double talk is present,
adjust the counter if the DT decision indicates that double talk is not present,
compare the counter to a specified counter threshold, and
determine whether or not to inhibit the updating of the set of filter coefficients based on the comparison of the counter to the specified counter threshold.

13. The one or more non-transitory machine-readable storage media of claim 12 , wherein to set the counter to the specified hangover value comprises to dynamically select the specified hangover value based on a duration of current inhibition of the updating of the set of filter coefficients.

14. The one or more non-transitory machine-readable storage media of claim 13 , wherein to dynamically select the specified hangover value comprises to:
set the specified hangover value to a relatively long hangover value if the duration of the current

Assignees

• Intel Corp

Inventors

• Tan Mizhou

Classifications

• H04M3/36

  Statistical metering, e.g. recording occasions when traffic exceeds capacity of trunks · CPC title

• H04B3/234 Primary

  using double talk detection · CPC title

• H04M9/085

  using digital techniques (H04M9/082 takes precedence) · CPC title