  IEEE 802.11ax uses the concept of primary and secondary channels, leading to
the Dynamic Bandwidth Channel Access (DBCA) mechanism. By applying DBCA, a
wireless station can select a wider channel bandwidth, such as 40/80/160 MHz,
by applying the channel bonding feature. However, during channel bonding,
inappropriate bandwidth selection can cause collisions. Therefore, to avoid
collisions, a well-developed media access control (MAC) protocol is crucial to
effectively utilize the channel bonding mechanism. In this paper, we address a
collision scenario, called Outside Warning Range Problem (OWRP), that may occur
during DBCA when a wireless station interferes with another wireless station
after channel bonding is performed. Therefore, we propose a MAC layer
mechanism, Intelligent Bonding Avoiding Collision (IBAC), that adapts the
channel bonding level in DBCA in order to avoid the OWRP. We first design a
theoretical model based on Markov chains for DBCA while avoiding the OWRP.
Based on this model, we design a Thompson sampling based Bayesian approach to
select the best possible channel bonding level intelligently. We analyze the
performance of the IBAC through simulations where it is observed that,
comparing to other competing mechanisms, the proposed approach can enhance the
network performance significantly while avoiding the OWRP.
