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Communications Technology Laboratory

Public Safety Communications Research Division

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Mission Critical Services (MCX)

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The Mission Critical Services (MCX) portfolio concentrates on four areas of communications for first responders: direct mode, mission critical push to talk, Land Mobile Radio (LMR) to Long Term Evolution (LTE), and public safety user quality of experience (QoE).

Portfolio Problem Statement: Mission critical services do not consistently meet first responders’ reliability, performance, and interoperability needs as public safety transitions from legacy LMR systems (purpose built) to broadband communications (commercial focus).​

Mission:

To advance the availability and performance of mission critical services, forge partnerships to expand our sphere of research with well-qualified universities and agencies, and influence the standards community by participating in regular 3GPP and TCCA events.

Vision:

PSCR, through its research and encouragement of exploration in the area of MCX, will be seen as a trustworthy leader by the public safety community as broadband technology becomes ubiquitous.

Featured Projects

LMR-Broadband Interoperability and Standards Advancement​​

Project Goal: Drive the development of standards and products for Mission Critical Services (MCX) and enhance interoperability between Land Mobile Radio (LMR) and broadband systems through research, analysis, and active participation in standards organizations (e.g GCF, TCCA, 3GPP).​

Why it’s hard

The absence of established interoperability standards and a governing standards body for LMR/broadband communication systems, combined with limited knowledge about current interoperability solutions, poses a significant challenge to achieving seamless interoperability and reliable performance between these systems, ultimately impacting public safety communications. Contributing to international standards will ensure a U.S.-centric perspective on the transition of mission-critical communications to broadband.​​

Technical capabilities/approach

  • Establish a representative mission-critical communications lab integrating commercial LMR systems, MCPTT servers and Interworking Functions (IWF), ISSI, FirstNet, MCPTT applications, and broadband/LMR user equipment​

  • Conduct controlled baseline testing across LMR and broadband systems to benchmark end-to-end performance, interoperability behavior, and system limitations under hybrid operating conditions​

  • Apply MCV Quality of Experience (QoE) metrics to quantify the impact of network conditions on mission-critical voice performance​

  • Evaluate interoperability feature expectations across LMR–broadband interfaces to identify gaps and inconsistencies

Outcomes

  • Evidence-Based Input to MCX Standards to inform MCPTT priorities, QoS/QoE requirements, and standards evolution​

  • Continued expansion of formal conformance, performance, and interoperability testing though recognized 3rd party labs leading to certified products available to carriers and public safety.​

  • Ensure US requirements, measurement methods, and test procedures are driving factors in the global public safety broadband market.

Device-to-Device (D2D) QoE Performance and Evaluation​

Project Goal: Drive the development of D2D communication technology and standards for Mission Critical Services (MCX). Optimize the Mission Critical Voice (MCV) Quality of Experience (QoE) measurement system, engage with industry stakeholders and standards organizations, and establish the D2D test environment and measurement methods. Conduct comprehensive D2D research, with the results being shared with public safety agencies and standards organizations to inform the development of industry standards and R&D.​​

Why it’s hard

The project is challenging due to the early stage of broadband D2D (Device-to-Device) technology and evolving standards, but it is crucial for US public safety agencies as it addresses the need for reliable off-network communication—a key feature currently available in Land Mobile Radio (LMR) systems but lacking in broadband devices. The project's outcomes will not only enhance public safety in the US but also inform the development of global broadband standards, ultimately benefiting first responders and ensuring US leadership worldwide.​​

Technical capabilities/approach

  • Enhance and deploy a scalable QoE measurement system, including refactored software, improved test execution interfaces, and verified digital audio integration over USB-C​

  • Design, document, and implement realistic D2D test environments (including two-location testing) ​

  • Develop a comprehensive D2D test plan aligned with emerging standards and operational scenarios​

  • Execute controlled D2D tests, analyze collected data, and characterize performance under varying conditions​

  • Quantify D2D performance relative to traditional mission-critical communications to assess strengths, limitations, and suitability for public safety operations

Outcomes

  • Generate objective QoE-based performance data for D2D communications to support informed public safety adoption and system design decisions​

  • Benchmark commercial D2D implementations against mission-critical requirements to identify capability gaps and guide future product and standards development​

  • Deliver documented, repeatable D2D test environments, methodologies, and tools that can be leveraged by industry and standards bodies​

  • Provide evidence-based input to standards organizations to support the definition of D2D performance metrics, test procedures, and certification considerations

Publications

Quick Resources

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Advanced communications, Public safety, Resilience and Standards

Contacts

Created September 20, 2017, Updated June 8, 2026
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