A Case for Ultrawideband Concurrent Transmissions in Wireless Control

Wireless networked control systems (WNCS) are at the forefront of academic and industrial efforts, due to the high deployment flexibility and low cost offered by their untethered multihop operation. However, they pose the unavoidable challenge of matching the reliability and latency of wired systems, exacerbated by energy efficiency constraints. Mainstream solutions, in industry and academia alike, largely rely on the routing-based protocol stacks for IEEE 802.15.4 narrowband radios. We identify an alternative to the status quo in the unexplored synergy between concurrent transmissions (CTX) and ultra-wideband (UWB) radios. Low-power wireless stacks based on CTX are known to offer order-of-magnitude improvements w.r.t. mainstream ones in reliability, latency, and energy-efficiency—i.e., the key WNCS requirements above. UWB is very popular in localization applications but rarely considered in multihop networking despite its high data rate and resilience to interference, yielding a beneficial impact on the requirements above. We elicit the potential of this synergy via a novel UWB stack based on a state-of-the-art CTX design. We quantitatively demonstrate its effectiveness in supporting different closed-loop control strategies in a realistic scenario via experiments in a 36-node, 6-hop cyber-physical testbed enabling direct comparison between the original narrowband system and our UWB one. Results show that the UWB stack achieves <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10\times $ </tex-math></inline-formula> higher reliability and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times $ </tex-math></inline-formula> lower latency with half the energy consumption, pushing the envelope of low-power networking support for wireless control.