  Brun, Devetak, and Hsieh [Science 314, 436 (2006)] demonstrated that
pre-shared entanglement between sender and receiver enables quantum
communication protocols that have better parameters than schemes without the
assistance of entanglement. Subsequently, the same authors derived a version of
the so-called quantum Singleton bound that relates the parameters of the
entanglement-assisted quantum-error correcting codes proposed by them. We
present a new entanglement-assisted quantum communication scheme with
parameters violating this bound in certain ranges.
