Multipath fading occurs when signals reach a receiver via many paths & their relative strengths & phases change. Multipath fading affects most forms of radio communications links in one form or another.

What is multipath channel?

Multipath channel (MPC) allows you to code a single transmission group for host-to-host communication that uses multiple write-direction, read-direction subchannels, as illustrated in Figure 1.

What are the statistical models for multipath fading channels?

Clarke's model for flat fading, Saleh and Valenzuela indoor statistical model, two ray Rayleigh fading model are some of the statistical model for multipath fading channels.