## 1 Introduction
Third, issues may arise due to frequent topology changes resulting from time-fluctuating channel conditions, such as battery outages, changes in the physical environment, and node failure. Controlling dynamic topology changes is costly and may even require a global change. Fourth, it is difficult to determine the intercession relation among neighboring nodes due to different communication and radio interference ranges from each other and other interfering nodes that may not be involved with direct communication (this situation is known as interference anomaly) [20]. Fifth, during low contention, TDMA results in lower channel utilization and increased delays. These problems with TDMA demonstrate that TDMA is not a reasonable choice when used individually, even if an efficient TDMAschedule is used. CSMA is attractive due to its flexibility, simplicity, and robustness. CSMA does not need considerable setup support, such as clock synchronization and global topology information. The dynamic joining and leaving of nodes is handled efficiently without additional operations. However, these benefits may come at the cost of an increased amount of trial and error; a trial may face collisions when more than two nodes attempt to access the channel simultaneously, causing signal fidelity to decay at the destination. Collisions can occur in any two-hop neighboring nodes. Although collisions at a one-hop neighbor node can easily be reduced by using carrier sensing before transmission, carrier sensing is not controlled beyond one hop. This issue, called the hidden terminal problem, affects throughput, particularly in high-data-rate sensor applications. RTS/CTS is an additional method to deploy with _virtual carrier sensing_ in (CSMA/CA). The RTS frame consists of five fields include frame control, receiver address, duration, FCS and transmitter address. The CTS frame consists of four fields include frame control receiver address, FCS and duration. Although RTS/CTS can reduce the hidden terminal problem, it creates high overhead (40%-75%) in channel utilization due to control packets in WSNs [21, 22]. Scalability and mobility are major issues whenever a node changes. Hybrid MAC protocols also experience inter-cluster communications and require tight time synchronization. These hybrid MAC protocols also use long preambles (signals used to synchronize transmission timing between two or more nodes and systems) that consume bandwidth and increase channel utilization [23]. To address these issues, the BN-MAC mobility-aware hybrid protocol introduces cross-layering support to control mobility and uses short preamble messages to reduce bandwidth consumption. Combining CSMA and TDMA and including additional features, BN-MAC is a highly robust mobility-aware protocol for controlling timing failures, slot allocation failures, time-varying channel disorder, synchronization, and topological changes. In worst-case scenarios, the performance of BN-MAC will not be reduced because this protocol needs local synchronization at one-hop neighborhoods. Our analyses prove that the overall performance of BN-MAC will still be comparable to other hybrid MAC protocols when clocks are unsynchronized and slot allocation failure occurs. The remainder of this paper is organized as follows: in Section 2, we discuss the goals, challenges, and contributions of this research. In Section 3, we present related work on hybrid MAC protocols. In Section 4, the system model is discussed. In Section 5, the BN-MAC protocol design is presented. In Section 6, the automatic active and sleep (AAS) model is presented. Section 7 presents the intelligent decision-making (IDM) model to automatically place nodes into either active or passive mode. Section 8 describes the simulation setup and analysis of the results. In Section 9, we discuss the results. Finally, our conclusions are presented in Section 10.