  Quantum error correcting codes (QECCs) in quantum communi- cation systems has
been known to exhibit improved performance with the use of error-free
entanglement bits (ebits). In practical situations, ebits inevitably suffer
from errors, and as a result, the error-correcting capability of the code is
diminished. Prior studies have proposed two different schemes as a solu- tion.
One uses only one QECC to correct errors on the receiver's side (i.e., Bob) and
on the sender's side (i.e., Alice). The other uses different QECCs on each
side. In this paper, we present a method to correct errors on both sides by
using single nonadditive Entanglement-assisted codeword stabilized quantum
error correcting code(EACWS QECC). We use the property that the number of
effective error patterns decreases as much as the number of ebits. This
property results in a greater number of logical codewords using the same number
of physical qubits.
