Why LinkCapacityEstimator still use EWMA, not use EWMA & mean and deviation?

[lan muming]

My question is link estimate why not use EWMA & mean and deviation?

code as per the annotated section below

detailed code as below:

void LinkCapacityEstimator::Update(DataRate capacity_sample, double alpha /*, double h */) {

  double sample_kbps = capacity_sample.kbps();

  if (!estimate_kbps_.has_value()) {

    // aver_estimate_kbps = sample_kbps;

    // var_estimate_kbps = sample_kbps;

    estimate_kbps_ = sample_kbps;

  } else {

    // aver_estimate_kbps = (1 - alpha) * aver_estimate_kbps + alpha * sample_kbps;

    // var_estimate_kbps = (1 - h)var_estimate_kbps + (h)(|estimate_kbps_.value() - aver_estimate_kbps|);

    // estimate_kbps_ = aver_estimate_kbps + 4 * var_estimate_kbps;

    estimate_kbps_ = (1 - alpha) * estimate_kbps_.value() + alpha * sample_kbps;

  }

  // Estimate the variance of the link capacity estimate and normalize the

  // variance with the link capacity estimate.

  const double norm = std::max(estimate_kbps_.value(), 1.0);

  double error_kbps = estimate_kbps_.value() - sample_kbps;

  deviation_kbps_ =

      (1 - alpha) * deviation_kbps_ + alpha * error_kbps * error_kbps / norm;

  // 0.4 ~= 14 kbit/s at 500 kbit/s

  // 2.5f ~= 35 kbit/s at 500 kbit/s

  deviation_kbps_ = rtc::SafeClamp(deviation_kbps_, 0.4f, 2.5f);

}