Audit key to 800 MHz reband
The rebanding of 800 MHz airwaves ordered by the FCC in August is analogous to the painful act of changing the tires on a loaded bus while it is speeding down the highway at 70 miles per hour.
Radio system operators are not going to be able to turn off their networks while they are being retuned. In some cases, if the repeaters and other hardware are so old that they won’t retune, entirely new systems will have to be built, all while the systems remain in operation.
The order calls for Nextel Communications to reband 800 MHz spectrum to create two adjacent blocks — one for Nextel and one for public safety — in order to eliminate interference that is plaguing first responder communications nationwide. It promises to be the most complex spectrum re-shuffling ever undertaken. The goal of this article is to provoke sufficient forethought to keep the rebanding process from turning into a disaster for public-safety agencies.
Whether you are happy with the FCC ruling that will result in all of this energy and money being spent, one thing is certain: Interference does exist. Case in point: While de-bugging a strategic solution for a public safety entity in Houston, we could not understand why our software would sporadically stop decoding for many seconds for no apparent reason — that is, until we discovered a Nextel tower very near to our receive antennas. At that point, it all began to make sense.
This discovery caused us to move our entire development and production environment to a cleaner site about 2 miles away, at no small expense. There was no fighting what had to be done. The FCC’s allocation of the spectrum made sense at its inception. In practice, however, the RF emission from the Nextel systems (and other CMRS systems) makes managing the interference a moving target. Our inability to hear the control channel in that instance is exactly what happens when police, firefighters and others can’t key their radios at certain times.
Let’s put the issue in very simple terms. Suppose you have a row of yellow and blue spray paint cans and you want to paint a wall. Let’s say yellow is Nextel and blue represents public safety and others that are licensed in the 800 MHz band. We’ll line up the cans yellow, blue, yellow, blue, and so on — this is the way the 800 MHz frequencies were aligned by the FCC. Suppose, too, that we place the cans far enough apart so that, given what we believe is good practice and the specifications of the spray heads, the paint won’t intermix.
Now let’s paint. When we start spraying with all of these cans, moving them along the wall, we find that theory often loses something in practice because we get some green areas where yellow paint has over-sprayed into the blue. No matter how we try to explain that it shouldn’t happen, it does. And we have a mess. Rebanding says we’re going to move all of the yellow paint cans to one edge of the wall and all of the blue paint cans to another section of the wall, with enough space in between to make sure we don’t have the problem ever again. Rebanding cleans up spectrum. In computer terms, it is like using the disk defragmenter on a PC’s hard drive.
Let’s now discuss the logistical aspects of rebanding. When the Transition Administrator — the entity that will oversee the rebanding process — tells you that you need to be relocated, it is doubtful public-safety agencies will be handed a blank check. In fact, such agencies likely are going to be required to offer some sort of accounting that quantifies and justifies how much money will be needed to accomplish the move. To provide those figures, public-safety agencies will need to know precisely how many sites, repeaters, antennas, mobiles and portables they have, as these are the system components that are frequency sensitive.
Agencies also will need to have a totally clear understanding of the system components that can’t be retuned because they are too old or not flexible enough to make the change. Potentially, some agencies may need some, or almost all, of their equipment replaced with new technology. While this sounds like Christmas, here’s the catch: once a public-safety agency’s system accounting is accepted, the Transition Administrator won’t be inclined to revisit it. As one consultant recently told me, “I believe you’ll get one bullet to fire, and if you miss, getting another shot will be really difficult.” While it won’t be too difficult to count antennas and repeaters, the biggest variable is the quantity of mobiles and portables that public-safety agencies really have on their systems. They will need to do their homework and be ready when the time comes to turn in their assessments. That time will come very soon.
Some system owners will have good inventory records and will know what equipment actually is deployed in the field. However, from experience, we have learned that for more than 80% of system owners, such recordkeeping is the lowest item on their priority list, which means such records almost never are updated.
One Motorola SmartZone system operator told us that, after running software for 60 days to audit the radios actually talking on its system, they found more than 200 radios — worth about $600,000 — that had been forgotten. They just fell through the cracks. Should a public-safety agency underreport its needs to the Transition Administrator for retuning or new equipment, the balance might come out of the agency’s pocket, depending on when the discrepancy is discovered. At the very least, such an error likely would delay the rebanding process.
Consequently, public-safety agencies should start now — not next month — to get a handle on their radio inventories. The longer the lead time, the more accurate the assessment will be. Each should build a database consisting of the following essential information: model numbers, serial numbers, software versions, programmable features, department ownership and identification of cloned radios.
While the task may sound daunting, commercially available software tools can make the job manageable. These software tools can automatically listen to a system’s data control channel, which contains a wealth of information about the system’s radio traffic. They also can provide an organized list of every radio that talked, every talkgroup they used and every feature they used. This information can be combined with other data — such as model and serial numbers — to easily extract a list of radios that an agency thought it had, as well as radios it didn’t know it had.
From there, the data can be sorted based on frequency of use to develop a rebanding plan of attack. Radio suppliers can provide a list of model numbers that can be retuned and those that will not retune. Once rebanding is completed, public-safety agencies can use these same tools to verify that all radios made it through the transition and to provide a clean and updated inventory database that can be used going forward. All of this adds up to increased efficiency, both in operation and spectrum use. In the process, public-safety agencies just might find the proof they’ve been seeking to justify their requests for more channels.
In summary, I have no idea how to change the tires while that bus is speeding down the highway. The rebanding logistics will be tricky. Fortunately, there are many companies appearing on the scene that can act as a general contractor (or like AAA, to keep the metaphor alive) to help with the licensing, engineering, reporting, purchasing, auditing and hand-holding. However, one thing is certain: Public-safety agencies should use the techniques described here to conduct an accurate rebanding audit — and, in the process, avoid some of the potential heartburn — before the tire salesman shows up at their door.
Phil Burks is the founder and president of Burks GenCore Co. Inc. and The Genesis Group. GenCore has been enhancing Motorola SmartNet, SmartZone and Dimetra Trunking infrastructure in more than 30 countries since 1983 with software soluions. The Web site is www.GenesisWorld.com.