  We analyze the quality of the quantum information transmission along a
correlated quantum channel by studying the average fidelity between input and
output states and the average output purity, giving bounds for the entropy of
the channel. Noise correlations in the channel are modeled by the coupling of
each channel use with an element of a one dimensional interacting quantum spin
chain. Criticality of the environment chain is seen to emerge in the changes of
the fidelity and of the purity.
