  Holevo capacity is the maximum rate at which a quantum channel can reliably
transmit classical information without entanglement. However, calculating the
Holevo capacity of arbitrary quantum channels is a nontrivial and
computationally expensive task since it requires the numerical optimization
over all possible input quantum states. In this paper, we consider discrete
Weyl channels (DWCs) and exploit their symmetry properties to model DWC as a
classical symmetric channel. We characterize lower and upper bounds on the
Holevo capacity of DWCs using simple computational formulae. Then, we provide a
sufficient and necessary condition where the upper and lower bounds coincide.
The framework in this paper enables us to characterize the exact Holevo
capacity for most of the known special cases of DWCs.
