What Is LTE?


Over the past several years, there has been much discussion on the topic of a nationwide public safety broadband wireless network. This is where Long Term Evolution (LTE) impacts public safety broadband. Originally, 10 MHz of spectrum, known as the D-Block, went up for auction by the Federal Communications Commission (FCC) to be part of a commercial network including specific requirements defined by public safety (reliability, redundancy, priority, etc.). For a number of reasons, the auction failed. One of the most significant factors was the absence of a national standard, which is essential for nationwide interoperability.

In 2010, most national public safety organizations endorsed LTE as the favored technology for a nationwide interoperable wireless broadband network in the 700-MHz public safety band. On Dec. 10, 2010, the FCC's Public Safety and Homeland Security Bureau (PSHSB) adopted an order that establishes a technical framework to ensure interoperability in the public safety mobile broadband networks. The FCC order further states that the regional broadband networks being built must be technically compatible and fully interoperable with one another, as well as the nationwide network envisioned for America's first responders. In the FCC press release, James Arden Barnett Jr., rear admiral (ret.) and chief of the PSHSB, said, "There are many forces that pull against interoperability; this is why it is critical that we have an iron rule of interoperability for America's public safety mobile broadband networks." A number of FCC representatives reinforce that the goal is to establish and maintain an interoperable nationwide broadband network for public safety.

· The benefits. LTE is the latest standard in the mobile network technology timeline. The current generation of mobile telecommunication networks is collectively known as 3G (for third generation). The LTE network promotes that it is designed to transmit data wirelessly through a standard Internet protocol (IP) with much higher download speeds to support data-intensive services such as high-definition video and complex mapping tools. LTE is currently being rolled out by several wireless carriers for commercial use in 2011.

LTE technology is also designed to allow more simultaneous users with fewer dropped connections than the earlier 3G networks through an improved radio access network that expands transmitter range and capacity. LTE also offers an enhanced ability to prioritize users through IP-based traffic control tools and increased levels of security. The basic premise of LTE is that it will establish a nationwide standard that will be interoperable by creating a WiFi-like system, but much faster.

  • What about mission-critical voice communications (talk-around)? While an LTE network will provide faster downloads and significantly better performance than 3G, LTE does not provide mission-critical voice communications for public safety. This is because broadband device technology does not exist that can provide talk-around communications (the ability to communicate one to one or one to many in the absence of infrastructure), which is currently achieved through the local land mobile radio systems. Presently, there is some movement toward Voice over LTE (VoLTE), but that is similar to Voice over IP (VoIP); neither of these two applications is capable of replacing land mobile radio (narrowband) talk-around capabilities.
  • 4G summary. 4G networks will transform public safety communications in ways that are beyond imagination. Data in the form of digital images, high-definition video, unmanned detection devices, personnel tracking/accountability systems, vehicle locators and database queries will lead to enhanced "real-time" situational awareness for responders, incident commanders and local, state and national emergency operations centers. This technology will also transform Next Generation 911 with a much higher level of integration with and between 911 callers and emergency responders. As the 4G technology rolls out, there is momentum by major radio manufacturers to develop hybrid devices that will combine present-day land mobile (narrowband) radios with broadband capabilities.
  • What about WiMax? WiMax is another 4G broadband network that offers many of the same advantages of those listed throughout this column. While it is not the adopted standard, it offers many of the features discussed in this column.
  • Convergence. Our world is moving into a new era as applications, information, technology and connectivity are evolving into a period of convergence.

CHARLES L. WERNER, a Firehouse® contributing editor, is a 34-year veteran of the fire service and chief of the Charlottesville, VA, Fire Department. He serves on the Virginia Statewide Interoperability Executive Committee, Virginia Secure Commonwealth Panel, National Public Safety Telecommunications Council Governing Board and IAFC Communications Committee. Werner is chair of the IAFC Technology Council, first vice president of the Virginia Fire Chiefs Association and chair of the DHS SAFECOM Executive Committee.