STX-Vote: Improving Reliability with Bit Voting in Synchronous Transmission-based IoT Networks

TL;DR

This work tackles beating-induced errors in synchronous transmissions for IIoT, proposing STX-Vote, a bit-voting error correction that uses the redundancy inherent in STX to recover corrupted packets without extra airtime. At the receiver, STX-Vote maintains a per-bit voting array across multiple erroneous receptions and reconstructs the candidate payload; the reconstructed packet is validated with a CRC before acceptance. Evaluations include simulations across wide and narrow beating patterns for BLE 5 and IEEE 802.15.4, plus lab experiments on $nRF52840$-DK and real-world D-Cube testbeds, showing $PER$ reductions and $PDR$ gains up to about 28% depending on PHY. The findings indicate that STX-Vote provides a practical enhancement to STX-based networks, complementing existing error-correction schemes without increasing airtime and enabling more reliable IIoT deployments.

Abstract

Industrial Internet of Things (IIoT) networks must meet strict reliability, latency, and low energy consumption requirements. However, traditional low-power wireless protocols are ineffective in finding a sweet spot for balancing these performance metrics. Recently, network flooding protocols based on Synchronous Transmissions (STX) have been proposed for better performance in reliability-critical IIoT, where simultaneous transmissions are possible without packet collisions. STX-based protocols can offer a competitive edge over routing-based protocols, particularly in dependability. However, they notably suffer from the beating effect, a physical layer phenomenon that results in sinusoidal interference across a packet and, consequently, packet loss. Thus, we introduce STX-Vote, an error correction scheme that can handle errors caused by beating effects. Importantly, we utilize transmission redundancy already inherent within STX protocols so do not incur additional on-air overhead. Through simulation, we demonstrate STX-Vote can provide a 40% increase in reliability. We subsequently implement STX-Vote on nRF52840-DK devices and perform extensive experiments. The results confirm that STX-Vote improves reliability by 25-28% for BLE 5 PHYs and 8% for IEEE 802.15.4; thus, it can complement existing error correction schemes.

Figures (8)

• Figure 1: Beating effect when frequency offset transmissions overlap.
• Figure 2: Types of beating baddeley2023understanding.
• Figure 3: STX-Vote workflow at a receiver.
• Figure 4: The voting operation of STX-Vote at a receiver.
• Figure 5: The average PER for strong and weak beatings.