The ISM free-licence band is highly used by wireless technologies such IEEE 802.11, Bluetooth as well as additional private wireless schemes. This huge utilization increases dramatically the interferences (high Bit Error Rate) leading to lowering the reliability of such networks. Among these wireless-based technology, IEEE 802.11 suffers particularly from these high interferences since the wireless sender is confused by loss' origins (noise or collision). In fact, the contention resolution mechanism (known as Backoff Exponential Binary) used by 802.11 assumes that each loss in the network is caused only by collision and hence acts to overcome this situation by delaying the retransmission of the packet lost. However, this mechanism is not efficient when the wireless channel is deployed in noisy environments, where collisions are mixed with high BER-caused errors. In this paper, we adapt the RTS/CTS handshake mechanism to the noisy channel through two possible mechanisms. After that, we model the proposed mechanisms by a two-dimension Markov model and validate these models by NS2 -based simulations.