  A parity-check stopping (PCS) criterion for turbo decoding is proposed in
[1], which shows its priority compared with the stopping criteria of Sign
Change Ratio (SCR), Sign Difference Ratio (SDR), Cross Entropy (CE) and
improved CEbased (Yu) method. But another well-known simple stopping criterion
named Hard-Decision-Aided (HDA) criterion has not been compared in [1]. In this
letter, through analysis we show that using max-log-MAP algorithm, PCS is
equivalent to HDA; while simulations demonstrate that using log-MAP algorithm,
PCS has nearly the same performance as HDA.
