The July 2026 publication, Theoretical Performance of Off-network Mission Critical Services (Off-network MCX), provides one of the industry's most detailed technical assessments of how standards-based device-to-device (D2D) communications can support mission-critical operations when conventional network infrastructure is unavailable. The study brings together key performance indicators (KPIs), performance analysis, radio design considerations and optimisation techniques to help ensure Off-network MCX is robust, reliable and suitable for frontline public safety operations.

Unlike traditional direct mode communications available on TETRA, P25 and DMR systems—which primarily support push-to-talk voice—5G Off-network MCX extends direct communications to include Mission Critical Push-to-Talk (MCPTT), Mission Critical Video (MCVideo) and Mission Critical Data (MCData) using the 3GPP-defined NR Sidelink interface. This evolution enables first responders, railway operators, utilities, industrial organisations and defence users to maintain secure voice, video and data communications even when cellular coverage is unavailable or compromised.

The white paper also identifies the performance targets expected for Off-network MCX, including discovery time, call setup, mouth-to-ear latency, voice quality and relay communications. It further examines the technical factors influencing system performance—including spectrum selection, UE transmit power, maximum coupling loss, antenna configuration, synchronization, mobility and interference—while outlining optimisation techniques designed to improve coverage, capacity, latency and reliability.

As governments worldwide continue investing in broadband public safety networks and Future Railway Mobile Communication System (FRMCS) deployments, the publication provides valuable guidance for network operators, equipment vendors, device manufacturers and standards organisations developing next-generation mission-critical broadband solutions. By defining measurable theoretical performance expectations for Off-network MCX, TCCA aims to accelerate industry readiness for standards-based 5G direct communications and strengthen operational resilience in the most demanding mission-critical environments.

Download the whitepaper