# How to subtract echoed signal from mixture of voice and echo signal?

I am working on an echo removal project. So far, I have successfully identified the far-end signal of length 21 ms at a sampling rate of 48000Hz whose echo is present in my near-end signal of 21ms. I did it using Echo Detection and Delay Estimation using a Pattern Recognition Approach and Cepstral Correlation .

Now, I want to remove that far-end echoed signal from my near-end signal which contains(echoed signal of farend and voice).

Things I tried:

1. Time-domain subtraction of PCM signals. i.e $$y[n] = x_{ne}[n] - x_{fe}[n]$$, where $$x_{ne}[n]$$ is the near-end signal and $$x_{fe}[n]$$ is the far-end echo signal.
2. Spectral Subtraction technique Eliminate Signal A from Signal B. Even Ephraim-Malah

In both, I am not getting the expected result as for spectral subtraction I read that It works well when there is static noise or one signal is stationary. For non-stationary signals, it doesn't work well.

What are the other techniques to remove the echo in my scenario? Since I have identified the far-end chunk whose echo is present in the near end chunk, I just want to remove it from near end chunk.