Toward Intelligent and Resilient Public Safety Communications: A Comprehensive Review of FirstNet, 5G, AI, and Emerging Technologies

Reliable and resilient communication systems are indispensable for first responders, enabling rapid coordination and effective emergency response. However, traditional communication networks frequently encounter congestion, interoperability failures, and infrastructure collapse during large-scale disasters. To address these deficiencies, specialized networks such as the First Responder Network Authority (FirstNet) have been developed, leveraging advancements in Long-Term Evolution (LTE), Fifth-Generation New Radio (5G NR), and priority access mechanisms to enhance reliability and coverage. This comprehensive review examines the technological evolution of first-responder communication systems from legacy Land Mobile Radio (LMR) and Project 25 (P25) systems through modern broadband solutions. We systematically analyze key enablers including network prioritization with Quality of Service (QoS), Priority, and Preemption (QPP); dedicated spectrum allocation on Band 14 (758–768/788–798 MHz); Mission Critical Push-to-Talk (MCPTT), Mission Critical Video (MCVideo), and Mission Critical Data (MCData) standards defined across 3GPP Releases 13–18; network slicing for dedicated emergency virtual networks; and Multi-access Edge Computing (MEC) for ultra-low-latency field processing. Additionally, this study assesses the integration of artificial intelligence and machine learning for predictive network management, digital twin technology for infrastructure resilience simulation, Internet of Things (IoT) sensor ecosystems for enhanced situational awareness, and satellite communication systems—including emerging Low Earth Orbit (LEO) constellations—for connectivity in infrastructure-denied environments. We further examine real-world deployments through case studies encompassing Hurricane Katrina (2005), the September 11 attacks (2001), Hurricane Harvey (2017), the California wildfires (2018–2025), and the 2011 Great East Japan Earthquake, alongside global initiatives including the United Kingdom’s Emergency Services Network (ESN), the European Union’s Public Protection and Disaster Relief (PPDR) framework, and South Korea’s PS-LTE SafeNet. By synthesizing recent advancements across more than 120 scholarly and technical sources, this review provides a forward-looking roadmap addressing Sixth-Generation (6G) networks, terahertz communications, holographic situational awareness, augmented and extended reality for field operations, blockchain-secured data sharing, and cybersecurity frameworks. We conclude with policy recommendations and identify critical research gaps necessary to ensure a seamless, intelligent, and globally interoperable communication infrastructure for first responders.