Channels with a large Doppler spread have signal components that are each changing independently in phase over time.

Since fading depends on whether signal components add constructively or destructively, such channels have a very short coherence time.

Averaging is applied to enhance a time-locked signal component in noisy measurements.

Motion causes Doppler shift in the received signal components.

For example, D2, with one moment, easily encodes polynomials of one coefficient, or constant signal components.

The locations of the largest peaks of the estimation function give the frequency estimates for the signal components.

Short antenna separations increase the spatial correlation as adjacent antennas will receive similar signal components.

It then smooths out the signal components while preserving the edges.

These signal components are further referred to as "I" and "Q".

The output signal may be obtained by removing the other signal components with a filter.