Pure delay estimation
AssigneeTelefonaktiebolaget LM Ericsson (publ)
InventorsTönu Trump, Dan Lusk
Life of this patent
Estimating the term…
Abstract
A pure echo delay estimate of an echo path impulse response estimate represented by echo canceller filter coefficients is calculated. This is done by incrementing (S9) an assumed pure delay m, where m is a positive integer representing an offset of m filter coefficients into the echo path impulse response estimate, until (S8′) a predetermined filter coefficient dependent decision function exceeds a predetermined threshold function, and by representing (S10) the pure delay by the smallest integer mSTART that makes the decision function exceed the threshold function.
Claims17
A method of calculating a pure echo delay estimate of an echo path impulse response estimate represented by echo canceller filter coefficients, said method including
- incrementing an assumed pure delay m, where m is a positive integer representing an offset of m filter coefficients into said echo path impulse response estimate, until a predetermined filter coefficient dependent decision function exceeds a predetermined threshold function of an a priori probability P(m) that the first m filter coefficients represent only pure delay;
- and
- representing said pure delay by the smallest integer mSTART that makes said decision function exceed said threshold function.
A method of calculating a pure echo delay estimate, said method including
- estimating pure echo delays of a predetermined number of completed calls associated with a common route;
- determining an average delay from said estimated pure delays;
- and
- wherein each pure echo delay is estimated from an echo path impulse response estimate represented by echo canceller filter coefficients by performing the steps:
- incrementing an assumed pure delay m, where m is a positive integer representing an offset of m filter coefficients into said echo path impulse response estimate, until a predetermined filter coefficient dependent decision function exceeds a predetermined threshold function of an a priori probability P(m) that the first m filter coefficients represent only pure delay;
- and
- representing said pure delay by the smallest integer mSTART that makes said decision function exceed said threshold function.
Dependencies are inferred from the claim text.