The performance of the distributed coordination function (DCF) of IEEE 802.11 has been shown to heavily depend on the number of competing stations in WLAN. As the number of stations increases, the performance dramatically decreases since the probability of packet collision increases. Due to these reasons, there have been many research efforts to reduce the packet collisions via backoff reservation schemes. However, the schemes have limitations in that they cannot be implemented in currently deployed wireless devices since they require the header of IEEE 802.11 medium access control (MAC) frame to be modified. In contrast to the pre-existing schemes, without the modification of the MAC frame header, the proposed scheme, DBRS, mitigates the packet collisions using a novel distributed backoff reservation and scheduling scheme. Through extensive simulations, the DBRS scheme is proved that stations achieve higher throughput and better fairness compared with the legacy IEEE 802.11 DCF.