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If you have not heard about public-safety broadband during the past few years, you may be living in a remote area of the United States, or you may need hearing aids. Regardless, hundreds of millions of dollars have been spent promoting and developing a new system to provide public-safety-grade broadband service across the United States. The promoters of this service are saying every square meter of the United States will be covered. That will be truly great. We really need someone to make coverage great again.
As we in the radio business know, using 800 MHz spectrum and higher will not cut it. There are thousands of existing cellular towers, and there are huge gaps in coverage in the rural areas. A new concept and approach is needed. Can you imagine building thousands of towers across pristine rural countryside? It would be just like all those wind generators that dot the countryside.
One major requirement for providing the high speeds that public safety needs is wide frequency bandwidth. A review of technical literature provides an approximate data speed versus channel bandwidth chart. It is clear from this chart that 20 megahertz of channel bandwidth is needed. Now where to find it? Manufacturers keep looking higher — now all the way to 60 GHz with the great range of 100 yards or so.
“How about lower?” I kept thinking. Then it struck me like a piece of dangling waveguide! Low band! There is 20 megahertz of almost unused spectrum from 30 to 50 MHz. No one uses low band anymore. What about the existing users? Another rebanding project! Instead of moving the users to a new frequency band, they would be the first users of the new low-band broadband. They could “kick the tires” and would be the Spectrum Users Concept KickERS (SUCKERS).
Now that the spectrum has been determined, a successful approach must be developed. To be successful, one has to have not only the technology but the appropriate marketing approach and buzzwords. First, a catchy name! It does not have to mean anything. For example, LTE stands for Long Term Evolution. What does that mean? No one knows. Base stations are called “eNodebs” or “eNbs.” Where did that come from? So how about LbTE? Low-band Technology Evolution. Base stations will be LbeNbs. The hardest part is now complete.
Second, what about the actual technology? Something catchy is needed there as well. For those of us in the know, steampunk technology is the latest thing. What is steampunk? It is old technology that meets new technology like an electronic watch with tubes.
Figure 1 is a concept of what a steampunk LbeNb might look like in actual practice. The actual electronics used is that newfangled integrated circuit technology. It is too small to be seen by anyone over 30, so it is not shown for simplicity.
User devices, also known as user equipment (UE) in LTE lingo, will need to be designed. Current broadband systems have abandoned fix-mounted mobile units for portable units. This works fine where power levels can be kept low. However, in rural areas, power is king. Power is needed to reach long distances. Therefore, true mobile devices will need to be developed. Keeping with the steampunk theme, Figure 2 shows the author pointing to a conceptual physical mockup of a high-power UE or HPUE.
The next job is the portable unit. When in town, officers and firefighters will want a portable device. If there is an LbeNb located right in town, portables should work. The one drawback to LbLTE is that it requires a larger antenna size for maximum performance — 90 inches tall or so would be great. This is not a problem on a vehicle but does hamper portable use.
Portables could use an even more advanced technology called diversity receive or possibly multiple input multiple output (MIMO) technology. MIMO sounds so much cooler. The portable radio concept would use shorter antennas, but there would be two. These antennas would be tiny compared to the long 90-inch whip antennas. They may also need to be made from rare earth materials. So, they would be called Tiny Miny MIMO or TMMIMO for short. Figure 3 shows the author demonstrating a concept model of one of these units.
While some may laugh at this concept, how can it fail? The initial clever marketing words and acronyms have been developed. Attractive equipment concept models have been developed. There is 20 megahertz of unused spectrum. Truly, a concept for the future.
Joe Blaschka Jr. is principal of ADCOMM Engineering and a registered professional engineer (PE) in eight states. He has been working in the communications field for almost 40 years. This article is in honor of April Fool’s Day and is meant to be humorous.