A general formula for channel capacity

S. Verdu, Te Sun Han
1994 IEEE Transactions on Information Theory  
A formula for the capacity of arbitrary single-user channels without feedback (not necessarily information stable, stationary, etc.) is proved. Capacity is shown to equal the supremum, over all input processes, of the input-output inf information rate defined as the liminf in probability of the normalized information density. The key to this result is a new converse approach based on a simple new lower bound on the error probability of m-ary hypothesis tests among equiprobable hypotheses. A
more » ... ssary and sufficient condition for the validity of the strong converse is given, as well as general expressions for e-capacity.
doi:10.1109/18.335960 fatcat:pcg4rjztx5bh3h4ptqjpxp2yci