The Evolution of Mission-Critical Push-to-Talk Networks: 5G’s Role in Public Safety
Ken Bednasz discusses the role of MCPTT and 5G, the interoperability challenges as today more and more telecommunications companies deploy technologies optimized for MCPTT interoperability over LTE, 5G and LMR.
Present events like the 2020 COVID-19 recovery and others over the past years — including the 9/11 attacks and hurricanes Katrina and Sandy — have highlighted the serious problem of interoperability with push-to-talk systems among first responders. Land Mobile Radio (LMR) systems often cannot communicate with each other. This issue makes coordinating rescue efforts difficult and needlessly complicated, which is a problem that the communications and public safety communities have worked to address with interoperable mission-critical push-to-talk (MCPTT) protocols.
Several companies have developed MCPTT applications over broadband, including Qualcomm, Kodiak (owned by Motorola), Harris and ESChat. In the past few years, 3GPP created standards for MCPTT architecture and mission-critical data and video over cellular networks. Currently, many MCPTT applications are available through LTE, with mobile broadband meeting many emergency responders’ needs for reliable coverage, secure communication and real-time video sharing. Soon after the 3GPP standards were released, Ericsson debuted its MCPTT services at the Homeland Security exhibition at Milipol 2017 in Paris.
A recent survey found that “71% of public safety decision-makers plan to invest in 5G technology because of its ability to improve operational efficiency.”
MCPTT and 5G
MCPTT services connect first responders, transportation authorities, homeland security, other public agencies and even utility emergency response teams. Still, there are limitations. 4G spectrum bands have become crowded impacting communications and data and video transmissions. MCPTT over 5G networks may solve many of these issues as organizations, like the EU-funded initiative Next Generation Platform as a Service (NGPaaS), the National Public Safety Telecommunications Council (NPSTC), and the First Responder Network Authority, develop new standards.
5G networks are still in the early stages; however, a recent survey by Ericsson found that “71% of public safety decision-makers plan to invest in 5G technology because of its ability to improve operational efficiency.” A large part of 5G’s appeal for public safety lies in the enhanced internet of life-saving things (IoLST), including wearables, sensors, smartphones and drones that can collect, analyze and transmit data and high-resolution images rapidly between emergency responders and public agencies.
The promise of 5G’s reliable, low latency capabilities could make MCPTT over 5G networks an indispensable life-saving technology. Neither LTE nor 5G MCPTT can fully replace LMR systems, which are necessary while underground, deep inside collapsed buildings or in out-of-network geographical areas. The goal of most organizations is to make LMR interoperable with broadband MCPTT systems, creating seamless connections between them across national networks. The NPSTC, for example, has proposed several interoperable MCPTT talk groups, some of which would be fixed and some dynamic, or created on an as-needed basis.
LMR interoperability with 5G includes designated channels for out-of-network, air-to-ground and vessel-to-shore, short distance, direct mode, travel channels that support moving convoys, and other communication modes unique to the needs of emergency responders. Interoperability standards are supported by the development of 5G-based direct mode vehicle-to-everything (V2X) New Radio. As a technology developed for autonomous vehicles, V2X offers many solutions for MCPTT, MCVideo, and MCData services. Other 5G-based solutions, like multimedia broadcast multicast services (MBMS), also have applications for mission-critical use cases.
These mission-critical technologies are rapidly evolving as public-private partnerships work through the technological challenges of interoperability to standardize protocols across networks and national borders. Dual-mode LMR/MCPTT devices will help bridge old and new technologies. They should begin to deliver 5G-supported mission-critical push-to-talk services to first responders in 2019 as more telecommunications companies deploy technologies optimized for MCPTT interoperability over LTE, 5G and LMR.