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First Responders Need Data. Can LTE Networks Come to the Rescue?

Urban and rural network models could tell us how first responders get critical information

Push-to-Talk (PTT) radios are first responders’ primary means of communication in an emergency. These two-way radios rely on Land Mobile Radio (LMR) networks to carry signals. PTT radios and LMR networks are reliable and secure, and fire, police, and other emergency response teams know these systems well.

But voice radios are not enough anymore. Two-way radios can’t send pictures, blueprints, and maps and they can’t talk with units from other jurisdictions. Without these capabilities, communications could break down, jeopardizing rescue and response efforts.

These reliable PTT radios could get upgrades. Next-generation technological advancements have the potential to integrate video, data, and greater interoperability into the radios first responders already know and use.

But there’s a problem. The LMR networks these radios currently use can’t handle sending that much data. And while public safety could tap into commercial cellular networks, the availability and traffic loads of these networks vary across the country. Before rushing to make new data-capable radios, developers need to know how LMR networks are used around the country. And that information is scarce.

That’s why NIST’s Public Safety Communications Research (PSCR) Division funded the Public Safety Radio Data grant. The project aims to collect and publish active public safety radio system transmission data from LMR systems. This LMR traffic data can support efforts to develop public safety traffic models for more advanced telecommunication systems and technology, such as LTE. These traffic models will also ensure resources are allocated equitably and optimally, from cities to the countryside and everywhere in between.

Leveraging LTE to complement LMR

You’ve probably seen the words “LTE” pop up on your smartphone screen. LTE is a 4G technology that addresses some of the challenges of 3G by removing competing elements and making them more interoperable. Currently, LTE is very stable and more widely available than 5G.

If public safety organizations can further integrate LTE capabilities into their daily operations, teams could use two-way radios in the same way they use smartphones, with video, maps, blueprints, and photos as well as voice. Interagency coordination could become less challenging because responders from differing counties would be able to communicate with one another more easily. Adopting LTE for first responders could eventually help their devices work with 5G, and beyond.

Before public safety users switch their devices to LTE, better and more comprehensive LMR traffic data needs to be collected and studied. When are the networks busiest? Where are the LMR towers compared to the LTE towers? Are there competing signals nearby that could interfere with an emergency call? Scientists need this kind of information from urban and rural districts so the datasets reflect varying topologies and response patterns.

Mission-critical PTT handheld LMR radios provide reliable connectivity for first responders but do not support multimedia content.

NIST’s Public Safety Radio Data Grant

NIST awarded Texas A&M more than $900,000 in September 2021 to collect public safety LMR usage data and make the dataset available for research related to the comparison of LMR to LTE.

Texas A&M is in the process of curating an LMR dataset that includes special event, traffic, incident, and LMR tower location data to learn more about how, when, and for how long first responders communicate. Researchers can use this dataset to identify patterns in public safety call duration, frequency, and group interactions. User information is redacted to avoid any analysis of Personally Identifiable Information (PII).

Impacts of Rural Data Inclusion

To complete their project, Texas A&M is partnering with 10 public safety organizations across the country. These partnerships vary by organization size and geographic location, which ensure that the dataset represents features from urban, rural, and tribal public safety LMR applications.

This approach is significant because rural and urban areas face different challenges in wireless communication. In densely populated urban areas, coverage is usually not an issue due to the number of cell towers. However, there can be a lot of interference because of competing signals. Additionally, there is the urban challenge of indoor coverage, because going through walls can be difficult for cellular signals. In rural areas, interference is not an issue, but coverage may be limited due to cell tower sparsity.

By partnering with large and small organizations across the nation, Texas A&M’s dataset can produce stronger traffic models with less bias and more accurate, generalizable results. Ultimately, this helps ensure smaller communities are not left behind as LTE becomes more widely adopted by public safety.

The future of mission critical LTE

Whether in an urban or a rural area, emergency responders need to always remain connected. Advancing the adoption of public safety LTE in conjunction with LMR can leverage multimedia data capabilities with more reliable connectivity, helping ensure solutions are optimized for speed, simplicity, scale, and security.

For more information on NIST’s mission critical voice research and projects, visit our website and sign up for the mailing list.