EQueue-MAC: Enhanced traffic adaptive hybrid MAC protocol with IEEE 802.15.4e features for industrial applications

To extend the system life, duty-cycling technique is widely adopted in wireless sensor network. However, this technique also introduces limited throughput and extra packet delay to the system. To solve the problem, in this paper, we propose eQueue-MAC, a multi-channel traffic adaptive CSMA/TDMA hybrid MAC protocol with slotted channel hopping technique which is robust to external interference and can adapt to variable traffic loads. eQueue-MAC maintains high flexibility by allowing CSMA accesses in light traffic conditions. With traffic increases, eQueue-MAC utilizes the queue-length information to dynamically allocate TDMA slots to sensor nodes to deal with the burst traffic load. In addition, the up to date IEEE 802.15.4e slotted channel hopping scheme is adopted in the vTDMA period to mitigate the impact from external interference or multipath fading. We have successfully implemented eQueue-MAC on STM32W108 SOC chips and carried out extensive experiments to evaluate its effectiveness. The results show that eQueue-MAC achieves low packet delay and high throughput under various traffic conditions. Moreover, the proposed protocol has also shown its effectiveness in handling external interferences, making it suitable for various industrial applications.