I. Introduction
The task of transferring quantum information differs significantly from its classical (non-quantum) counterpart, since the laws of quantum mechanics limit the accuracy of information transfer through quantum channels. Specifically, the signal-to-noise ratio of possible quantum measurements on the transmission line is limited [4], reflecting the well known fact that a quantum state cannot be cloned at the remote location. This motivates a great interest in developing systematic methodologies for the design of optimally performing quantum communication systems.