A Comprehensive Survey on Decentralized Emergency Communication Frameworks: Bridging the Gap Towards Infrastructure-Independent Mobile SOS

Abstract

In the aftermath of catastrophic events, the immediate collapse of terrestrial communication infrastructures critically hinders search and rescue operations during the vital \"Golden Hour.\" While substantial research has explored ad-hoc networking, IoT meshes, and UAV relays to restore connectivity, many paradigms remain tethered to specialized hardware or cloud-synchronized control planes. This survey presents a thematic evaluation of recent advancements in decentralized edge communication, categorizing contemporary literature into clustering methodologies, multi-hop routing protocols, and resource optimization strategies. Through a rigorous gap analysis and a comparative study of eight state-of-the-art frameworks, this paper identifies critical systemic deficiencies in ubiquitous consumer hardware compatibility. We conclude by proposing MeshRelaya software-defined, energy-aware communication architecture utilizing native smartphone radios and a Gossip-based epidemic protocol to establish a self-healing emergency lifeline.

Introduction

The increasing frequency of natural disasters often causes the failure of cellular and internet infrastructure, making it difficult for affected individuals to send emergency messages and coordinate rescue operations. Traditional backup communication solutions such as satellite systems, temporary base stations, and LPWAN technologies are expensive, infrastructure-dependent, and vulnerable to single points of failure. To address these challenges, this study examines decentralized communication approaches and proposes MeshRelay, a smartphone-based emergency communication framework designed for infrastructure-free disaster environments.

A review of existing research identified three key areas of decentralized networking: topology management, multi-hop routing, and resource optimization. Various solutions have used clustering algorithms, Bluetooth Mesh, LoRa networks, vehicle-to-vehicle communication, UAV relays, and optimization techniques to improve communication reliability. However, most existing systems suffer from limitations such as dependence on specialized hardware, reliance on cloud servers or 5G infrastructure, high computational complexity, excessive battery consumption, or poor suitability for dynamic smartphone-based disaster scenarios.

The analysis revealed three major gaps in current solutions: hardware exclusivity, infrastructure dependency, and the trade-off between communication efficiency and computational complexity. Most frameworks require equipment such as LoRa transceivers, Raspberry Pi devices, or specialized antennas, while others depend on cloud synchronization or cellular base stations. Fully decentralized approaches often experience broadcast congestion and battery drain, making them unsuitable for large-scale emergency use.

To overcome these limitations, the proposed MeshRelay system is designed as a lightweight, software-only solution that operates entirely on standard smartphones using built-in Bluetooth Low Energy (BLE) and Wi-Fi Direct capabilities. The framework employs a decentralized Epidemic Gossip Protocol for message dissemination, enhanced with sequence-number caching, local SQLite storage, and Time-To-Live (TTL) controls to prevent redundant message forwarding and broadcast storms. A lightweight Utility Scoring Function selects optimal relay nodes based on battery level and signal strength, improving energy efficiency and routing reliability. BLE is used for low-power device discovery, while Wi-Fi Direct handles high-speed data transfer.

Conclusion

This survey confirms that while high-performance mesh architectures exist, they lack the \"ubiquitous accessibility\" required for civilian emergency response. MeshRelay represents a shift toward software-defined resilience, proving that existing smartphone hardware, when orchestrated through intelligent Gossip protocols and SQLite persistence, can form a viable, self-healing lifeline.

References

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Copyright

Copyright © 2026 A R Sagar, Ashish G Shetty, G Shashank , Harish Gowda S, Hemalatha K. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.