Emergency first responders finally saw some progress last year for the roll-out of the nation’s first dedicated wireless broadband network for public safety, administered by the First Responder Network Authority (FirstNet). Although it is still early in the FirstNet network’s evolution, it is surprising to see that the topic of in-building coverage lacks any clear direction, so far.
Emergencies happen everywhere, and 80 percent of all emergency calls originate indoors, according to the 2016 National 911 Progress Report. When 911 operators receive emergency calls, most of the time they dispatch first responders. Therefore, public safety communications data coverage within buildings sufficient to guarantee the use of FirstNet services is critical to protecting the lives of members of the public and the lives of first responders.
When the U.S. Congress in 2012 established FirstNet, it gave the authority the mission to deploy a nationwide broadband public safety network to promote nationwide interoperability.
Over the past year, FirstNet and other stakeholders have made a lot of progress in bringing this network to life. In March 2017, FirstNet awarded AT&T the contract for building out the network. Since then, the FirstNet has been busy working out the deployment details. Each of the 56 states and territories have received a plan and, as of this writing, 31 states and territories have opted in to the FirstNet network. States and territories that participate will not have to cover the cost of the radio access network (RAN) for the next 25 years. Initially, the sale of communications airwaves spectrum will cover the cost of the RAN. This method of funding is designed to help start the network deployment. So far, Congress has raised $7 billion through the sale by FCC auction of radio-frequency (RF) spectrum, with none of the money coming from taxpayers.
However, a reading of initial public documents and the nature of discussions conducted during town hall meetings have revealed that the FirstNet network requirement of in-building coverage and what it takes for in-building wireless standards and strategy have received little focus. Overlooking the critical elements of standards and strategy for in-building wireless coverage will jeopardize the effectiveness of such a mission-critical service.
However, many buildings, especially new LEED-certified buildings, do not allow RF signals to propagate throughout the building. Building materials made for energy efficiency, such as low-e glass, can attenuate radio signals that pass through them and thus reduce the strength of wireless signals used for both commercial and public safety purposes indoors.
Additionally, concrete, drywall and even free-air loss (signal loss that occurs as the radio wave travels through the air from the transmitter site to the receiving location) all contribute to RF attenuation. This makes it more and more difficult to create an optimal wireless communications system without some sort of signal booster, bidirectional amplifier (BDA) or distributed antenna system (DAS) to enhance the signals indoors.
If the first responders are unable to access FirstNet network services indoors, then is this service truly providing the value that was intended when it was first devised?
The service’s initial documentation contains little language addressing in-building coverage. The original directive of the network involves deployment on the macro network. Policies for regulating the codes for in-building coverage were not included.
However, National Fire Protection Association (NFPA) and the International Fire Council (IFC) have developed model fire codes pertaining to in-building booster systems for public safety communications that apply at the national or global level. States, counties, municipalities and other jurisdictions make local decisions on how to interpret and apply these model codes. These organizations have created or have suggested specific public safety code requirements for in-building RF radio coverage for voice communications — from specifying minimum signal strength for emergency responder communications (−95dBm), to defining the coverage area (90 to 95 percent of the building), to 12- or 24-hour battery backup requirements for communications systems. The code bodies NFPA72 and IFC510 lead the effort to define the standards for public safety in-building communications at the local jurisdiction level.
One of these governing code bodies could introduce a regulation for the FirstNet network that would require LTE services testing similar to what is required for voice communications. For public safety voice communications, the building must meet a delivered audio quality (DAQ) score that meets the definition, “Speech understandable with repetition only rarely required. Some noise/distortion.” Testing would be carried out in every part of the building with each part of the building sectioned off according to a grid. Each grid section must meet the DAQ score for the whole building to be approved. The table on Page 00 shows the DAQ scale.
By requiring a similar data-oriented test for FirstNet network LTE services, first responders can rest assured that no matter what part of the building they are in, they will receive a sufficient level of signal service to be able to use the data services that are being delivered.
Although deployment of the FirstNet network has already begun for opt-in states, many see the lack of clear in-building network services coverage requirements as a big hole that needs to be addressed to ensure that first responders who would want to use its services would have ubiquitous access. Comba’s public safety CriticalPoint BDAs and soon-to-be-released fiber DAS are able to support FirstNet’s LTE Band 14 operations, but the next step is to ensure that authorities having jurisdiction (AHJs) require such access as part of their codes. Although manufacturers will do their part to make sure that the FirstNet network will provide service inside buildings, nonprofit organizations such as the Safer Buildings Coalition, of which Comba is a member, also recognize the need for in-building coverage for FirstNet network services. Through their leadership, the nonprofit organizations are focused on advancing the policies, ideas and technologies that ensure comprehensive in-building communications capabilities for public safety agencies and the people they serve.
It is our hope that when the FirstNet network is fully deployed, it will fulfill Congress’ vision of a reliable nationwide, interoperable, secure and innovative broadband network for public safety not only for outdoor coverage, but also indoors.
Jeff “JR” Wakabayashi is the marketing manager at Comba Telecom, North America, where he promotes brand awareness by implementing strategic marketing plans for the region. Prior to joining Comba, he was the global marketing manager at Patriot Memory. He is a member of APCO, and he participates with the Safer Buildings Coalition as an Education Committee member.