To improve the performance of RTS/CTS scheme in error-prone WLAN channel, this paper proposes an enhanced scheme utilizing Back-to-back DATA Retransmission and packet loss differentiation. With this new scheme, the packet which encounters transmission error can be retransmitted continuously without additional backoff time and RTS/CTS handshake. The system performance of this enhanced scheme is evaluated by a three dimensional Markov chain model. The numerical results show that this new scheme can improve the saturation throughout and reduce packet delay in error-prone channel.