FirstNet will build a new Band Class 14 network designed to be reliable, functional, safe and secure, and to provide optimal levels of operational capability at all times. Public safety communications for the first time will be based on commercial standards, bringing the benefits of lower costs, consumer-driven economies of scale and rapid evolution of advanced communication capabilities.

LTE Technology

By law, the network is to be based on minimum technical requirements that meet the commercial standards for long term evolution (LTE) service, or wireless communication of high-speed data, now in its fourth generation. FirstNet is involved in the standards process and working closely with public safety organizations to support the development of functionality that meets the needs of the public safety users that FirstNet will serve. Much of the current focus is on an international set of standards that will allow FirstNet to offer mission-critical voice (MCV) when these capabilities become available. The same MCV technologies will then work across all standards-based equipment and networks worldwide.

FirstNet broadly defines its LTE network in distinct layers: core network, transport backhaul, radio access network (RAN) and public safety devices.

Long term evolution networks distinct layers

Core Network

FirstNet is responsible for building the enhanced packet core network, a key component for ensuring that users have a single interoperable platform nationwide. The core network has six primary functions: it switches data, processes and reformats information, stores and maintains data and keeps it secure. Applications and services and operational and business support systems also reside in the core network. The core will interface with other state, local and federal networks, including 911 and the internet. Essentially, the core serves as a giant umbrella covering all of the US, including the territories and the District of Columbia. The core is connected to radio access networks in each state via the backhaul layer of the network.

Transport Backhaul

Backhaul carries the voice, data and video traffic on the network. Backhaul provides the connections between cell sites and the core wireless broadband network. Backhaul will also connect FirstNet to the internet and other networks such as 911 centers. Typically these connections are made via fiber optic and microwave technology. To meet the reliability needs of public safety, backhaul will be redundant wherever feasible to ensure that network traffic continues to flow during periods of extreme network demand and stress.

Radio Access Network (RAN)

The RAN portion of the network consists of the radio base station infrastructure that connects to user devices. RAN includes cell towers as well as mobile hotspots embedded in vehicles that backhaul to the core network over satellite or other types of wireless infrastructure.

Comprehensive RAN planning is required to optimize coverage, capacity and performance for a nationwide network. Initial modeling has shown that tens of thousands of radio base stations are needed to cover at least 99 percent of the population and the national highway system. Population coverage alone won’t suffice for public safety. State by state, FirstNet needs to understand public safety coverage needs.

During consultation, FirstNet will work with the states to determine the coverage expectations and priorities that must be included in the RAN deployment plan to enable public safety to meet its mission, no matter where it takes them.

RAN Reliability

The very circumstances that can require first responders to come to the aid of others can also wreak havoc on RAN sites when first responders need coverage the most. Making a system reliable requires physical and operational redundancy and hardening.

Most network outages are due to power failures and the loss of data links. To be public safety-grade, FirstNet sites will need redundant power backup that relies on a variety of sources. Power, backhaul, sites and coverage will be designed with the goal of avoiding single points of failure.

Public Safety Devices

Devices are all the user access points that will send and receive information over the network. Everything from smartphones to laptops, tablets, dongles and a wide variety of specialty devices will be developed for FirstNet users. The goal is to create devices that are rugged enough to withstand the many public safety environmental issues, but still be easy to use and convenient to carry. Devices will also have to be easy to administer and secure.

With the potential for millions of users, FirstNet will have the scale and leverage to drive development and procurement of devices at the best possible prices. Scale can also spur interest from a number of new vendors, which can enhance vendor/design diversity, increase competition and help lower prices for public safety devices. In the future, FirstNet will work with industry to develop device types and applications to meet public safety use cases identified by public safety users. FirstNet devices and applications will undergo a variety of testing and certification in areas including interference, operation, environmental factors and security.