Echo cancellation in the network for data applications
AssigneeLucent Technologies Inc.
InventorsDONALD LARS DUTTWEILER, DAVID GOODWIN SHAW
Life of this patent
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Abstract
A network-based CODEC (coder-decoder) includes an echo canceler. This CODEC recognizes the presence of a data call by detecting predefined signaling portions of a modem handshaking process. For each detected data call, the CODEC uses a stored channel model for performing echo cancellation during the data call. The CODEC trains off-line during selected segments of the modem call and then stores the new channel model for use in a future data call.
Claims42
Apparatus for use in a network, the apparatus comprising:
- a network echo canceler that performs echo cancellation during a data call, where the network echo canceler is trained off-line.
Apparatus for use in echo canceling, the apparatus comprising:
- a decoder for decoding a coded signal and for providing a decoded signal;
- an analog to digital converter for converting a received analog signal into a digital signal;
- an echo canceler responsive to the decoded signal and operative on the digital signal for providing an echo-canceled signal;
- and
- a coder for coding the echo-canceled signal into a coded signal;
- wherein the echo canceler uses coefficient values determined off-line.
Apparatus comprising:
- an analog-to-digital converter for converting an analog signal to a digital signal;
- an echo canceler operative on the digital signal for providing an echo-canceled signal;
- a coder operative on the echo-canceled signal for providing a coded signal;
- and
- a signal detection element for detecting the presence of a data call and controlling the operation of the echo canceler in response thereto such that the echo canceler is operative during a detected data call and the echo canceler uses a set of tap coefficient values that are determined from a previous call.
A method for use in equipment for echo canceling a data signal for use during a data call, wherein equipment is different from the respective data communications equipment endpoints of the data call, the method comprising the steps of:
- detecting the presence of a data call;
- and
- if a data call was detected, echo canceling a respective signal of the data call after analog-to-digital conversion of the signal and before coding of the signal;
- wherein the echo canceling step uses tap coefficient values determined from a prior data call.
A method for use in equipment for echo canceling a data signal for use during a data call, wherein equipment is different from the respective data communications equipment endpoints of the data call, the method comprising the steps of:
- detecting the presence of a data call;
- and
- performing an analog-to-digital conversion of an analog signal, of the data call, to provide a digital signal;
- if a data call was detected, echo canceling the digital signal to provide an echo-canceled signal;
- wherein the echo canceling step uses tap coefficient values determined from a prior data call.
Dependencies are inferred from the claim text.