A Survey on LoRa-Based Multi-Hop Communication Systems for Vehicular Accident Detection and Emergency Response

This survey reviewed existing accident detection and emer- gency alerting approaches across LoRa-based, cellular, and hybrid communication frameworks. The analysis showed that single-hop LoRa systems, despite their long-range and low- power benefits, fail to maintain reliability in highway and rural environments due to the absence of cooperative forwarding and the requirement of a directly reachable receiver. Cellular- only methods also remain limited in regions with weak or inconsistent coverage. Through comparative assessment, it became evident that no existing system provides continuous delivery under mobility, sparse connectivity, and infrastructure limitations. These gaps motivated the development of a hybrid multi-hop LoRa– GSM architecture that integrates threshold-based sensing, dy- namic packet creation, peer-to-peer relaying, and opportunistic GSM/cloud transmission. The proposed workflow ensures that alerts propagate across vehicles until a connected node is reached, improving dependability in real-world deployment scenarios. Overall, the findings indicate that combining LoRa’s peer- to-peer resilience with GSM’s wide-area reach enables a robust, scalable, and low-cost solution for vehicular emergency alerting. Such hybrid designs represent a practical direction for enhancing road-safety communication systems, especially in variable or low-connectivity environments.  

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