LoRa Sync Paper Accepted in IEEE Transactions on Wireless Communications

José \'Alamos, Thomas C. Schmidt, Matthias Wählisch,
LZn: Robust LoRa Frame Synchronization Under Frame Collisions and Ultra-Low SNR Conditions,
IEEE Transactions on Wireless Communications, 2026. (in press)
[pdf][BibTeX][Abstract]

Abstract: LoRa has become a widely adopted wireless modulation scheme in LPWANs due to its low cost, long range, and minimal transmission power. However, collisions between frames of the same spreading factor – common in dense LoRa deployments – prevent conventional LoRa receivers from detecting and correctly decoding frames. Recent work has introduced methods to improve recovery, yet their detection stage degrades sharply under low signal-to-noise ratio (SNR) and high collision rates. In this work, we introduce LZn, a low-complexity synchronization scheme driven by a minimum-based spectral intersection across consecutive symbols. Our method enables robust frame synchronization even under multiple packet overlaps or extremely low SNR conditions. We evaluate LZn on simulations and three independent, real-world LoRa datasets. LZn improves detection sensitivity by up to 10,dB and increases detection probability by up to $1.54times$. In real-world datasets, LZn improves decoding by $3.46times$ in the most challenging single-user scenario and up to $1.22times$ in collision scenarios compared to the second best collision-tolerant scheme (TnB). These results demonstrate that LZn substantially improves the frame recovery of LoRa receivers, while remaining compatible with real-time requirements.

Note: accepted for publication

Themes: Internet of Things