Voice Communications, without Limitations
Historically accepted limitations of where a firefighter can and cannot communicate are being challenged through innovation and next-generation technologies.
The world of two-way radio voice communications has a long and robust history of providing reliable communications in the most difficult environments. Despite an ever changing communications world, with cellular voice and high-speed data available at ever decreasing costs and continually expanding coverage, the public safety community continues to rely almost entirely on two-way radio voice communications. Arguments against the change to newer technologies such as 3G/4G cellular include overloading of public networks during major emergencies, lack of robust equipment designed for the harsh public safety environment and security of information (privacy) when using public networks. While these concerns have long been valid, and continue to be the case in some instances today, a growing number of companies and customers are learning to manage these perceived weaknesses while still using the tremendous strengths these other technologies provide.
Two-Way radio communications has provided communications for firefighters for the past 50 years. While the technology has vastly improved over this time, the innovation surrounding the basic operation has not changed much since the advent of trunking technology. Initial radio communications on the fire ground was for communications between the incident and the station, not between individual firefighters. Over time this evolved to allow each firefighter to carry a radio into the fire, an advancement that has saved countless lives. More and more channels were added to these initially simple systems which resulted in the last great innovation of two-way radio communications; trunked radio. Trunked radio finally allowed users in the field make use of a large number of radio channels in the most efficient
ways possible while still allowing a simple user experience.
As these technologies grew, from basic conventional VHF communications to larger, more capable trunking networks, the reliance on these networks, as well as the costs, grew substantially. Advancements in digital radio communications further added to this, allowing for more channels using the same amount of frequency spectrum. Digital radio brought with it a suite of additional features and clearer voice communications, however the onset of these various technologies that would not interoperate with each other created its own set of issues.
Two-Way Voice Today
Today’s two-way radio networks have advanced FAR beyond where they first started. Digital technologies such as P25, DMR and Tetra have been adopted by public safety agencies all over the world. Analog FM radio is the technology that still makes up the majority of the radio networks around the world but that is changing though as costs for digital two-way technology slowly drops. With the adoption of digital radio communications comes the entry into the world of data and IP networks. Users of these new digital networks continue to push for more information which further pushes the technology to the limit.
With increased capability, come increased costs. The price to deploy a wide-area digital radio system, dedicated for the use of one or more public safety agencies, is high. As agencies move to these technologies, with the hopes of enjoying the latest features of a digital radio system, trade-offs must be made. More often than not, the trade-off is system coverage.
Designing a new radio network to communicate with these devices is an expensive endeavor. Public safety agencies do not have the benefit of putting up radio towers everywhere (like they do in the cellular world) as the price for these sites is very high. Therefore, proper planning must be done to ensure that the most radio coverage can be provided in the most cost-effective way. Often, the result is a radio system designed to communicate with high power radios found on a vehicle while outdoors, and not the portable radios on a person. In the end, this results in a “successful” radio system design that lacks the coverage required by a large majority of its users when indoors. If only all major incidents occurred outside where the radios worked well, but perhaps, there is a way to get the best of both worlds.
As the world of two-way radio has slowly been moving to the digital era, the world of IP networks has quickly arrived and been absorbed. Any radio technician that has worked on a digital radio system today will tell you that a background in IP and networks is almost mandatory. While this is not a surprise to anyone in the radio industry, it is interesting to see how the old habits of radio system design continue to remain. Relying on pure radio technologies with slow adoption of newer technologies due to old reasons is a common problem that holds back the ability for Public Safety agencies to use their radio systems where they want, when they want, without limitation.
In discussions with the head of any public safety agency today, their issues will be immediately obvious. When asked what the users of their system do when they cannot talk on their radio, the answer usually comes in two forms: “move to a location where the radio works” or “use your cellular phone”. Unfortunately public safety operations are not that easy to move to a location that works, which leaves the use of a cellular phone as an ongoing and common solution to a VERY common scenario.
Historically there have been some simple technologies that agencies could use to solve these problems. This has included transportable repeaters, vehicular repeaters and Bi-Directional amplifiers; each with their own pros and cons. Bi-directional amplifiers are permanently installed into buildings, requiring significant design and installation costs. Vehicular repeaters provide the benefit of extending a trunking system’s coverage to a nearby portable radio, but they are limited to the street and require connectivity to the existing trunking system. Transportable repeaters offer unlimited flexibility in where they are located, but provide only communications to the users on scene and not back to a central command or dispatch.
If the common approach is to use cellular phones to communicate when radio communications do not work, perhaps the combination of new and existing technologies can remove some of the trade-offs currently accepted in the two-way radio systems. As mentioned before, the world of IP networks is already fully embraced by the two-way radio industry. Cellular data systems, IP data networks and digital radio systems all have the potential to form a very powerful solution.
A hybrid approach
Transportable repeaters offer a simple solution with a set of limitations preventing their wide scale use in the industry. The most common limitation for a transportable repeater is its lack of connectivity back to a central headquarters or dispatch; or even to additional transportable repeaters in a wide-area deployment. Other limitations may include large repeater size, complexity to deploy (requiring a radio technician) and the passing of digital radio signals and encryption to allow digital radio features to be properly utilized (a common issue with repeaters made up of two mobile radios). Overall, the main issue that continues to prevent transportable repeaters to be used as a regular solution remains lack of connectivity outside of the fire ground or area of operations.
With the advent of digital radio protocols such as P25 and DMR, the ability to connect these radio systems over an IP network has become very simple. Open standard protocols such as the P25 Digital Fixed Station Interface (DFSI) and the DMR equivalent allow the very low data rate of a digital radio signal to be passed from a repeater to a central server for distribution to a headquarters or dispatch facility. Instead of legacy technologies that simply passed analog voice, users on this system are now passing their digitally encrypted voice AND radio data such as Unit IDs and Emergency messages over a network.
Agencies currently using these digital technologies have already embraced cellular 3G/4G networks as a solution of last resort. If this is already the case, then perhaps the use of these well-established cellular networks should be further considered. 3G/4G networks are currently being deployed around the world at a rate never seen before. The coverage and reliability of these networks continues to improve while the limitations do still remain, although to much less degree. The addition of a 3G/4G backhaul for a transportable repeater would now allow for the digital radio interface to connect to any device, on any network. The combination of these technologies could allow users to use their existing, trusted digital radios in locations they have never dreamed of.
Two-Way Radio of the future
The capabilities and limitations of the two-way radio systems currently in use in the Public Safety industry have not changed significantly for a very long time. New radio system designs continue to accept limitations that are historical and based on legacy. As more and more technologies become available, it is imperative that they be considered; not for complete change, but to compliment the very robust systems that are already in use. The world continues to demand more and more capability in their communications which continues to drive innovation. Technologies such as HF Radio, Satellite, microwave, LTE, MIMO and others are amazing feats of engineering that could further enhance the radio systems that are relied upon every day to save lives. Let’s continue to ask how we can improve the ability to communicate in the Public Safety world, wherever, whenever.
For further information, go to www.codanradio.com