Delay spread

In telecommunications, the delay spread is a measure of the multipath richness of a communications channel.

The importance of delay spread is how it affects the Inter Symbol Interference (ISI).

If the symbol duration is long enough compared to the delay spread (typically 10 times as big would be good enough), one can expect an equivalent ISI-free channel.

The correspondence with the frequency domain is the notion of coherence bandwidth (CB), which is the bandwidth over which the channel can be assumed flat (i.e. channel that passes all spectral components with approximately equal gain and linear phase.).

Delay spread has a significant impact on Intersymbol interference.