Echo and near-end crosstalk cancellation system
An echo and near-end cross-talk (NEXT) cancellation system includes a time-domain processing module and a frequency-domain processing module. The time-domain processing module is configured to receive an unprocessed signal after an analog-to-digital conversion, remove at least one time-domain dominant component of interference from the unprocessed signal, and accordingly cancel a time-domain processed signal. The frequency-domain processing module is connected to the time-domain processing module, and configured to receive the time-domain processed signal, cancel at least one frequency-domain component of the interference from the unprocessed signal, and accordingly generate a processed signal.
1. An echo and near-end crosstalk cancellation system, comprising:
a time-domain processing module configured to receive an unprocessed signal after an analog-to-digital conversion, cancel at least one time-domain component of interference from the unprocessed signal, and generate a time-domain processed signal; and
a frequency-domain processing module configured to receive the time-domain processed signal, cancel at least one frequency-domain component of the interference from the time-domain processed signal, and generate a processed signal;
wherein the time-domain processing module further comprises a time-domain channel estimation unit and a time-domain echo and near-end crosstalk cancellation unit, wherein the time-domain channel estimation unit is configured to receive the unprocessed signal and a transmitting data, wherein the interference is coupled from the transmitting data,
wherein the time-domain channel estimation unit acquires a plurality of time-domain channel coefficients according to the unprocessed signal and the transmitting data, and the time-domain echo and near-end crosstalk cancellation unit acquires the time-domain component of the interference according to the time-domain channel coefficients.
2. The echo and near-end crosstalk cancellation system as claimed in claim 1 , further comprising one end for receiving the unprocessed signal, and another end for receiving the transmitting data.
3. The echo and near-end crosstalk cancellation system as claimed in claim 2 , wherein:
the time-domain channel estimation unit is configured to perform a channel estimation algorithm to obtain N initial time-domain channel coefficients; and
the time-domain echo and near-end crosstalk cancellation unit is connected to the time-domain channel estimation unit.
4. The echo and near-end crosstalk cancellation system as claimed in claim 3 , wherein the time-domain echo and near-end crosstalk cancellation unit is configured to receive the transmitting data and the time-domain channel coefficients, and calculate a plurality of time-domain dominant components of the transmitting data through K channel coefficients selected from the time-domain channel coefficients.
5. The echo and near-end crosstalk cancellation system as claimed in claim 4 , wherein K is a positive integer selected from 1 to N, wherein N is a number of points or a number of samples used in a fast Fourier transform for frequency-domain processing.
6. The echo and near-end crosstalk cancellation system as claimed in claim 5 , wherein the time-domain processing module further includes a first adder connected to the time-domain echo and near-end crosstalk cancellation unit for subtracting the time-domain dominant components from the unprocessed signal, so as to generate the time-domain processed signal.
7. The echo and near-end crosstalk cancellation system as claimed in claim 6 , wherein the frequency-domain processing module further includes:
a first fast Fourier transformer configured to receive the time-domain processed signal, and convert the time-domain processed signal into a frequency-domain unprocessed signal;
a second fast Fourier transformer configured to receive the transmitting data, and convert the transmitting data into a frequency-domain transmitting data;
a frequency-domain adaptive filter updater connected to the first fast Fourier transformer and the second fast Fourier transformer, and configured to receive the frequency-domain unprocessed signal and the frequency-domain transmitting data, so as to train or update a plurality of frequency-domain channel coefficients; and
a frequency-domain echo and near-end crosstalk cancellation unit connected to the frequency-domain adaptive filter updater.
8. The echo and near-end crosstalk cancellation system as claimed in claim 7 , wherein the frequency-domain echo and near-end crosstalk cancellation unit is configured to receive the frequency-domain transmitting data and the frequency-domain channel coefficients, and calculate a plurality of frequency-domain residue components of the frequency-domain transmitting data through the frequency-domain channel coefficients.
9. The echo and near-end crosstalk cancellation system as claimed in claim 8 , wherein the frequency-domain processing module further includes a second adder connected to the frequency-domain echo and near-end crosstalk cancellation unit for subtracting the frequency-domain residue components from the time-domain processed signal, so as to generate the processed signal.
10. The echo and near-end crosstalk cancellation system as claimed in claim 9 , wherein the first fast Fourier transformer receives the time-domain processed signal through the second adder, or receives another time-domain signal that is outputted from another module and adapted to the frequency-domain adaptive filter updater.