Integrating Land Mobile Radio and Broadband Networks is a Necessity

Roughly a decade ago, Congress approved deployment of a public safety broadband network by the First Responder Network Authority (FirstNet). Many people in the sector — me included — thought that this marked the beginning of the end for land mobile radio (LMR). Click Here to listen to a MCP related podcast.

The reasoning was fairly simple. On the one hand, paying to operate, maintain, and upgrade an LMR system while also subscribing to FirstNet’s network would be cost-prohibitive for all but the largest jurisdictions — and likely even for them. On the other hand, it seemed only a matter of time before a “mission critical” voice component was added to Long-Term Evolution (LTE), the technology that provides the backbone of FirstNet’s network and other broadband networks serving the public-safety sector. LTE initially was contemplated solely for data transmission, but technology evolves at warp speed, and it seemed intuitive that LTE eventually would be capable of delivering public safety-grade voice.

Now I’m not so sure. In fact, I’ve come around to the thinking that LMR systems and broadband networks will coexist in the public-safety sector for quite some time. Here’s why:

• While the standards-development body Third Generation Partnership Project (3GPP) has made solid progress in adding mission-critical voice to LTE, it has failed to deliver reliable talkaround communications. Also known as device-to-device communications, talkaround enables emergency responders to communicate with any device that is within range of their radio. This is essential when responders are unable to connect to a repeater on the LMR system.
  • For example, large structures, especially those constructed of concrete, e.g., warehouses, are notorious for disrupting radio signals. If firefighters battling a warehouse fire were caught in a mayday situation and couldn’t connect to the LMR system, their lives would depend on the ability to communicate with other firefighters in close proximity via talkaround. Until that capability comes to LTE, the voice provided by such networks might be called “mission-critical,” but it won’t be public-safety grade. Said another way, if an LTE network doesn’t provide talkaround, then there’s nothing to talk about.
• LTE networks also are unable to provide the point-to-multipoint communications that are the hallmark of LMR systems. Considered in concert with talkaround, this is vitally important given that voice communications always will be the lifeblood of emergency responders.
• In addition, LTE networks cannot approach the coverage performance of LMR systems. This is because LTE networks are provisioned by commercial, for-profit entities that need to justify their infrastructure investments. Simply, if the population density needed to generate sufficient revenue doesn’t exist, then the commercial entities will avoid building out the infrastructure. This means that rural areas likely will experience significant coverage gaps, and this can occur even in urban environments. Conversely, public safety LMR systems are designed and engineered to deliver 95 percent coverage across the jurisdiction’s footprint, and often approach 98 percent or better.
• However, all of that said, LTE networks are the gold standard when it comes to transmitting data that will exponentially enhance situational awareness for emergency responders, both in the 911 center and in the field. This involves the amount of data that can be transmitted as well as the type of data. For example, streaming video is just one of a plethora of high-bandwidth data types that would choke and LMR system. In comparison, LMR systems, for the most part, are limited to transmitting text and, perhaps, thumbnail photos.

Perhaps in a nod to the reality that LMR systems and public-safety broadband networks will coexist for quite some time, major device manufacturers have brought to market devices capable of toggling between an LMR system and an LTE network. However, those devices are expensive, in the neighborhood of $10,000 per device, about twice the cost of a Project 25 (P25) digital LMR radio, and thus might be out of reach for many agencies. Fortunately, workarounds already exist. The Inter-RF Subsystem Interface (ISSI), which is a component of the P25 standards suite, enables an LMR handset to connect to an LTE network. Conversely, applications exist that enable smartphones operating on an LTE network to connect to an LMR system.

The simple truth is that emergency responders need the voice capabilities provided by LMR systems and the rich data capabilities that LTE provides, to do their jobs better and safer. State and local officials need to provide them with these capabilities. We would welcome the opportunity to help your agency develop a strategic plan for integrating your LMR system with an LTE network, which will maximize how well these capabilities are leveraged — please reach out.

Scott Neal is vice president and director of wireless services. Prior to joining the firm, Scott was a major with the Pennsylvania State Police overseeing the Pennsylvania Statewide Radio Network (PA-STARNet). Email him at ScottNeal@MissionCriticalPartners.com.