Design of the MAC protocol is crucial in all wireless sensor networks (WSNs) due to its influence on the performance of the transceiver, i.e. the most energy-consuming component of each sensor node. A mechanism known as “carrier sense multiple access with collision avoidance” (CSMA/CA) is used for accessing the wireless channel in the IEEE 802.15.4 standard-based MAC protocol in order to avoid collisions between the network’s communicating nodes. CSMA/CA relies on two clear channel assessments (CCA=2) for checking the status of the channel. In this paper, we develop an additional CCA algorithm for the two scenarios encountered in star topology-enabled WSNs. Next, we investigate the impact of an additional clear channel assessment (CCA=3) on performance in IEEE 802.15.4. We develop a Markov chain model for the proposed methodology, and validate it using Matlab. Simulation results show that there is a significant improvement of performance metrics in the IEEE 802.15.4 standard-based MAC protocol with an additional CCA
Enhanced Segmentized Clear Channel Assessment Method for IEEE 802.15.4 Network