Analysis and Experimental Evaluation of IEEE 802.15.4e TSCH CSMA-CA Algorithm

Time Slotted Channel Hopping (TSCH) is one of the MAC behavior modes defined in the IEEE 802.15.4e standard. It combines time slotted access and channel hopping, thus providing predictable latency, energy efficiency, communication reliability, and high network capacity. TSCH provides both dedicated and shared links. The latter are special slots assigned to more than one transmitter, whose concurrent access is regulated by a CSMACA algorithm. In this paper we develop an analytical model of the TSCH CSMA-CA algorithm to predict the performance experienced by nodes when using shared links. The model allows to derive a number of metrics such as delivery probability, packet latency and energy consumption of nodes. Also, it considers the capture effect that typically occurs in real wireless networks. We validate the model through simulation experiments and measurements in a real testbed. Our results show that the model is very accurate. Also, we found that the capture effect plays a fundamental role as it can significantly improve the performance experienced by nodes.