Methods and systems for reducing acoustic echoes in communication systems

A method for computing a control state of a communication system, the method comprising:

• providing a first digital signal and a second digital signal, the first digital signal produced at a first location, and second digital signal encodes an acoustic echo and sounds produced at the second location;
• computing an average square energy, Ex2(m), associated with the first digital signal, an average square energy, Ey2(m), associated with the second digital signal, and an average square energy, E r2(m), associated with noise, at a decision epoch m of a decision period having Nd time samples;
• computing a maximum square energy of the first digital signal and a maximum square energy of the second digital signal, at the decision epoch m;
• computing variances in the average square energies associated with the first digital signal, the second digital signal, and the noise, at the decision epoch m;
• and
• computing the control state by comparing the average square energies, the maximum square energies, and the variances, at the decision epoch m.

A system for reducing an acoustic echo in an audio signal comprising:

• a computer system that runs a computer program;
• and
• a program stored in memory and having instructions enabling one or ore processors to perform the operations of:
• receives a first digital signal and/or a second digital signal, the first digital signal encodes sounds produced at the first location and the second digital signal encodes an acoustic echo and sounds produced at the second location;
• computes a control state identifying the signals as being output from the first location and/or the second location;
• computes an approximate acoustic echo of the acoustic echo detected at the second location based on the control state;
• subtracts the approximate acoustic echo from the second digital signal to produce an output digital signal:
• and
• transmits the output digital signal to the first location.