问ergodic channel

The channel gain process is ergodic. You may want to ask yourself what is an
ergodic process. if that 's also a question mark for you, find a good stoch
astic book to look up.

Ergodic channel
The channel gain process is ergodic, i.e., the time average is equal to the
ensemble average.   In other words, the randomness of the channel gain can
be averaged out (removed) over time.  So long-term constant bit rates can
be supported (like AWGN channels).
Non-ergodic channel
The channel gain is a random variable and does not change with time.  The c
hannel gain process is stationary but not ergodic, i.e., the time average i
s not equal to the ensemble average.   In other words, the randomness of th
e channel gain can not be averaged out (removed) over time.  So long-term c
onstant bit rates can not be supported.
normally, if the Dof in fast fading channel is very high, a fast fading cha
nnel can be classified into ergodic channel. coz this channel supports cons
tant bit rate, and randomness of the channel gain is averaged out due to in
dependent signal paths.
u can turn to "digital communication over fading channels"(M. K. Simon) or Matthias Potzold`s book for help