Two-Way Radio Is Different from Cellular WirelessMonday, June 08, 2009
I am frequently asked, since I have a foot in both worlds, why two-way radio users don't simply move over to commercial wireless systems. Many of today's commercial systems offer push-to-talk and group PTT, so why do these entities still spend hundreds or thousands of dollars on two-way radio services? There is both a long and short answer, but today I will concentrate on the short answer. The longer one could end up as a white paper for the commercial wireless industry.
I am bringing up this topic now because the two-way radio community needs to be aware of a petition (see PDF at the bottom of the righthand side of this page) in front of the Federal Communications Commission (FCC) and to support it, and many of my readers are deeply involved in the two-way radio industry. Further, I thought it would be an interesting blog post for those who have never been exposed to two-way radios except, perhaps, to use family radios or a CB radio.
Two-way radio systems have some attributes and capabilities that today's commercial wireless systems do not. The first is one-to-many dispatch. Wait, you say, we can do one-to-many PTT on our commercial network. This is true, but one-to-many in this case might be one to 5, 50, 100, or more depending on the type of network. Then there is the issue of coverage. Two-way radio systems are all local in nature, having been designed to cover a specific area very well, and this coverage has been beefed up and added to over time. In most cases, two-way radio systems provide better coverage for their users than commercial systems can provide today. Further, equipment requirements are completely different. Two-way radios mounted in vehicles have powerful amplifiers to provide loud voice audio from a loud speaker. Without the driver or others having to pick up a device, everyone in the cab can hear the message, and even when they are out of the vehicle, they can hear the dispatcher. Bluetooth is not a satisfactory replacement because the audio volume of in-vehicle Bluetooth devices cannot be sufficiently amplified.
All two-way radios can be operated with one hand. A speaker mic on a shoulder or a mic in a car can be operated with a single push of a button and users can talk to whomever they need to communicate with. When both hands are busy, they can still hear the radio traffic on the channel. When a group of vehicles are close to each other, they can use a mode of operation known as simplex, which you might think of as peer-to-multipeer. With simplex, communications are unit-to-unit and do not go through a cell site or base radio repeater system and this is a very important feature of all first responder systems. There are other reasons as well, but these serve to explain why two-way radio will not be replaced by commercial cellular-type networks for primary communications for some time to come, though many of these systems are beginning to be interconnected to commercial networks and their PTT systems.
Few people in the commercial cellular industry understand the issues being faced by companies and services that operate two-way radio systems. While the commercial world is going broadband, and hopefully first responders as well, two-way radio operators in the United States that have been using channelized communications since the 1930s are being told by the FCC that they must reduce the size of their channels by half (in most cases from 25 KHz to 12.5 KHz). This is certainly foreign to the commercial side of wireless where the trend is to move to broadband cannels and deploy technologies that make it possible for many devices to share the same spectrum.
While two-way radio services are also wanting broadband data services, operators are not going to give up their two-way, push-to-talk voice dispatch systems anytime soon, and it makes little sense with today's wireless technologies for two-way radio customers to have to "narrowband" their systems. Even so, all of the systems operating in many of the radio bands must replace or modify their radios to conform to the new narrowband standard by Jan 1, 2013. This move began in 2004, so many two-way radio customers have been purchasing radios that are, today, capable of both wideband (25 KHz) and narrowband (12.5 KHz). Most of them will be ready before the deadline, so getting the equipment to meet the requirements appears to be on track, though it is causing economic distress because of the costs involved.
What is not on track is the licensing process. Two-way operators must hold a valid license issued by the FCC, but prior to filing for the license, they must go through a process known as frequency coordination, which is designed to minimize interference from one system to another (many systems share the same channelized portion of the spectrum). The process can be long and involved, and it goes through organizations that represent one of two classes of two-way radio licenses. For example, public safety organizations go through the Association of Public Safety Communications Officials (APCO), which for many years has had volunteer frequency coordinators who are charged with reviewing every application for public safety channels designated for law enforcement. Other organizations have primary responsibility for other portions of public safety spectrum including the International Association of Fire Chiefs and IMSA for fire and emergency medical services, the Forestry Conservation Communications Association, which is responsible for spectrum supporting our forests and wild lands, and the American Association of State Highway and Transportation Officials representing the broad gamut of surface, water, air, rail, and public transportation. The work they do is tedious and time-consuming-sometimes tests need to be run between two systems, and channels have to be coordinated by the type of signaling to keep out any traffic not intended for the system as well as the type of system (analog FM or digital).
One of these organizations, the American Association of State Highway and Transportation Officials (AASHTO), provides coordination services for its members that operate on public safety spectrum. Though the FCC does not necessarily consider all AASHTO members as first responders when it comes to the public safety broadband system, local government service and first responder spectrum have been combined and all users can use any frequency available with little exception, and some frequencies are set aside for emergency medical use-but who qualifies as a first responder is a story for another day.
AASHTO (a non-profit association) coordinates radio channels for the organizations responsible for 4 million miles of roads and highways, 5,200 public-use airports, 26,000 miles of navigable water channels, 4,450 miles of commuter rail, and approximately 168,000 miles of bus and transit lines-in other words, many organizations that need two-way radio services on a daily basis and are on a par with the first responder community. There are also organizations that coordinate business band radio systems, trucking companies, taxicabs, and other types of vertical market two-way radio spectrum users.
Each applicant pays a small fee for this coordination, and any changes to the system that require a modified license must be re-coordinated, which brings me to the point of this article.
At issue at the moment is that in an attempt to tie this all together, the FCC is requiring all current license holders operating between 150 MHz and 512 MHz to apply for a license modification adding the designator for narrowband and later removing the designator for wideband-which means every application must go through a frequency coordination process twice.
This is turning into a nightmare for all of the coordination agencies, let alone the license holders. AASHTO is the first coordination organization to recognize this issue, and since its membership is large, with radio licenses held by members numbering in the thousands, it has taken the lead and has filed a petition with the FCC requesting that the rules be modified to allow a current license holder to receive an updated license without having to go through the coordination process simply to remove a wide bandwidth designator.
I believe this petition filed by AASHTO makes sense and is a move in the right direction. If approved by the FCC, the change will enable all land mobile radio license holders caught in the narrowbanding hassle to more simply and economically file for a license modification, it will greatly reduce the workload for the already overloaded volunteer frequency coordinators, and it will reduce the FCC's workload. There is no downside here, and I urge all frequency coordination groups to support this petition for rulemaking.
Andrew M. Seybold