Are Group Acknowledgements Worth Anything in IEEE 802.15.4 DSME: A Comparative Analysis

For data collection scenarios in the industrial Internet of Things, wireless communication offers a cost-effective and easy-to-deploy alternative to wired networks. Especially when data needs to be forwarded via multiple battery-powered nodes to a gateway for analysis in the cloud, high energy efficiency and reliability are required. IEEE 802.15.4 DSME acknowledges every packet individually (ACK), imposing an overhead for each transmitted packet and increasing energy consumption. In networks with little interference, it may thus be beneficial to aggregate ACKs for multiple nodes and broadcast them in a compressed format. This paper compares different of these group acknowledgment (GACK) schemes in best-case and worst-case scenarios and proposes novel GACK schemes to examine whether GACKs constitute a viable alternative to regular ACKs. Results indicate that GACKs can provide a 17% higher reliability than regular ACKs in a best-case scenario. On the other hand, they reduced reliability by at least 15% in comparison to regular ACKs in all other scenarios. Experiments on hardware do not indicate lower energy consumption.