Assessing the Effectiveness of Channel Hopping in IEEE 802.15.4 TSCH Networks

Time slotted channel hopping (TSCH) is an enhanced access mechanism for IEEE 802.15.4 that improves many aspects of the original protocol, like determinism and power consumption. Besides preventing collisions, time slotting allows motes to stay asleep for most of the time. In addition, channel hopping achieves more stable communication, in terms of packet losses and transmission latency, in spite of wireless spectrum variations. In this article, the specific effects of the latter mechanism are investigated from both qualitative and quantitative points of view. In particular, a thorough experimental campaign was carried out on real devices, deployed in a real environment and performing realistic data exchanges, when they are exposed to different interference conditions, to assess the benefits it brings over the case when transmissions are performed on a fixed-channel (FC). Experimental results confirm that, when the transmission frequency is kept repeatedly changing, communication quality is sensibly less affected by colocated Wi-Fi infrastructures, which makes the network behavior more predictable, and hence, intrinsically more dependable.