Channel coding 1 Direct sum 1 Error correction 1 Error correction codes 1 Errors correction 1 Hilbert space 1 Hilbert spaces 1 Mutually unbiased basis 1 Projective measurement 1 Property 1 Protocols 1 Q measurement 1 Q measurements 1 Quantum communication 1 Quantum entanglement 1 Quantum information theory 1 Quantum optics 1 Superdense coding 1 Symmetric basis Vector spaces 1