Replacing the FCC with "don't be spectrum selfish."

Radio technology has advanced greatly in the last several years, and will advance more. When the FCC opened up the small “useless” band where microwave ovens operate to unlicenced use, it generated the greatest period of innovation in the history of radio. As my friend David Reed often points out, radio waves don’t interfere with one another out in the ether. Interference only happens at a receiver, usually due to bad design. I’m going to steal several of David’s ideas here and agree with him that a powerful agency founded on the idea that we absolutely must prevent interference is a bad idea.

My overly simple summary of a replacement regime is just this, “Don’t be selfish.” More broadly, this means, “don’t use more spectrum than you need,” both at the transmitting and receiving end. I think we could replace the FCC with a court that adjudicates problems of alleged interference. This special court would decide which party was being more selfish, and tell them to mend their ways. Unlike past regimes, the part 15 lesson suggests that sometimes it is the receiver who is being more spectrum selfish.

Here are some examples of using more spectrum than you need:

  • Using radio when you could have readily used wires, particularly the internet. This includes mixed mode operations where you need radio at the endpoints, but could have used it just to reach wired nodes that did the long haul over wires.
  • Using any more power than you need to reliably reach your receiver. Endpoints should talk back if they can, over wires or radio, so you know how much power you need to reach them.
  • Using an omni antenna when you could have used a directional one.
  • Using the wrong band — for example using a band that bounces and goes long distance when you had only short-distance, line of sight needs.
  • Using old technology — for example not frequency hopping to share spectrum when you could have.
  • Not being dynamic — if two transmitters who can’t otherwise avoid interfering exist, they should figure out how one of them will fairly switch to a different frequency (if hopping isn’t enough.)

As noted, some of these rules apply to the receiver, not just the transmitter. If a receiver uses an omni antenna when they could be directional, they will lose a claim of interference unless the transmitter is also being very selfish. If a receiver isn’t smart enough to frequency hop, or tell its transmitter what band or power to use, it could lose.

Since some noise is expected not just from smart transmitters, but from the real world and its ancient devices (microwave ovens included) receivers should be expected to tolerate a little interference. If they’re hypersensitive to interference and don’t have a good reason for it, it’s their fault, not necessarily the source’s.

The truth is, if you follow these rules there is an absolute ton of spectrum out there. There’s no shortage at all. The shortage is created because the FCC allocates wide swaths of spectrum to people who barely use it, use it badly and have no incentive to improve. With no spectrum allocation the capacity of the ether is immense, especially as we put in more and more wires for the long hauls. The more wires do the long haul, the more we do our radio short range where we can. Without powerful transmitters blasting at you, each tiny cell of spectrum has terabits of capacity for local traffic, including local traffic to wires that will send it to another tiny cell with terabits. If only the people who truly need to go long distances to locations that can’t be wired, their needs are small.

In the extreme, consider free-space-optics, with infrared lasers. Strictly line of sight, short haul, but with gigabits of bandwidth per link. It’s so directional that you could have almost an arbitrary number of gigabit links flying through the air in a tiny space. And the next block could have another, independent pile of gigabit links. The shorter distance the radio links go, the more you can pack per square mile — your total capacity is immense.

One of the rules I talk about — use the latest technology — does require an arbitrary time guideline. It will be the case that some people install a network based on today’s latest technology, and a year later its obsolete and quite selfish compared to something newer. People need to manage risk, so we probably would not immediately declare this technology selfish and demand its replacement. In order to give people time to plan and write things off, they would be allowed to use now-selfish technologies of a certain age. But I don’t think that age should be more than a few years, not with the pace things are moving at.

Indeed, not preparing for the fact that technology will change is a selfish activity. If you design a technology and don’t make it easy to replace how the radios work after 5 years, that’s your bad unless you can show a compelling reason.

It’s not that there won’t be compelling reasons for certain selfish activities. Directional antennas, which need people to aim them, can cost a lot more than omnis. Sometimes “doing it cheaper” so that more people can adopt a technology can be a reason to not be a perfectly unselfish player in the spectrum cloud. That’s why a court-like body with a mandate for the eventual deprecation of older precedents may make more sense than a complex set of rules.

One case I would like to consider is emergency and military radios. There’s a big push right now to increase the special spectrum for “first responders,” and to come up with standards so that police can talk to medics and firefighters and so on. On top of that, they want mechanisms to shut down “civilian” radios to make sure the emergency users can get through.

This is totally backwards, but it has appealing soundbites — “Do you want the ambulence driver to not hear your address because everybody is on the phone during a terrorist attack?”

There is more than enough spectrum for everybody if we do it right and aren’t selfish. Enough so that everybody can be on the phone at once.

If emergency services people decided to use consumer technologies, they would gain from the vast economies of scale and huge pace of innovation that comes from mass market technology. Their radios would be compatible with everybody else’s, of course — including the civilians who often perform a major role in emergencies. The emegency responders would get radios for 1/10th the price that do ten times as much. That’s how consumer technology works. And they would not have to shut off the victims at the top of the World Trade Center having their last conversations with loved ones (or sending vital information to first responders) in order to do it. (How’s that for an emotionally charged soundbite?)

Of course, something as radical as this is not going to happen all at once. However, it can be tested by allocating more and more of the existing spectrum to this regime. That would include lots of currently unusused spectrum (talk about selfish) including all unused TV channels. (It’s possible selfish allocation of a few new TV channels could continue, with devices in that band simply knowing enough to not use any band with a licenced carrier.)

I believe that such an experiment would surpass even what the 2.4ghz experiment demonstrated, and take us on the path to the more complete deregulation.

Comment on Radio/Interference

Hi Brad,
Regarding Amateur (Ham) Radio, at least, there are regulations which stipulate which party must correct interference; these regs do follow common sense. In truth, most operators operate in a good faith manner.

I do agree with using the internet whenever possible; again, in Amateur Radio, this technology shift has been felt; many operators use packet-based communications, etc. via the internet.
Regarding interference "in the ether", we perceive the interference at the receiver, because that's how we hear it. There are occasions, however, when 2 distinct signals operating at the same frequency, but originating from different sources, can find themselves in the same space at the same time. It is for this reason that some transmitters (ususally FM) transmit at much higher power levels during the day than they do in the evening, because of ionospheric ceiling changes. I recall travelling back home from the NJ shore to my home in Northern NJ and there was a distance during which the FM signal 92.7 recieved by my car's FM radio kept switching between the South-Jersey based WOBM and the Long Island based WLIR, and that happened despite FCC transmission power regs.

for whatever it's worth :-)

Earl

Interference

Radio waves do not interfere in space. Two radio waves can pass through one another without effect. Interference only occurs when they both reach the same receiver on the same band with sufficient power for the unintended one to disrupt the intended one. The higher the frequency, the more bound the path of the waves can be. Low frequency waves like FM will spread everywhere, they should only be used when that is the goal — to go everywhere. High frequency waves can have directional transmitters and receivers that will only interfere when two transmitters are along the line the directional receiving antenna (or in particular dish) is aimed — or over a wider swath when the application demands less directionality in the antenna. And again, only if the unwanted transmission has enough power to interfere with the desired signals, since they should be using a noise tolerant system.

Low frequencies should be used only for rural applications, where you need to go long distances to mobile devices.

Alas, the news for hams is not good under my regime. Hams would have to stop using bands the way they do, and experiment with new technologies to be unselfish. But in fact that’s what being a ham is all about, after the initial learning phase. It’s not about using ancient technology, it’s no longer about code, and if you want to socialize with remote people, there are far better and less selfish ways to do that now.

Though on the other hand, there really is so much spectrum out there, if we opened it all up, that there should be enough for people to “play” and experiment and engage in activities that would be selfish if there were other people with a better use for the spectrum. But if there aren’t, then hams could feel free. No need for a licence, actually.

omnis!!!

I think that some may have comments on most of your ideas, but surely everyone agrees that omnis can be a menace?? That's what I hear from the WISPs I talk to.

Omnidirectional antennas

Have their place, of course. For handheld devices, for example and today for most mobile devices. (It's not that hard to imagine, however, the availability of mass-produced directional self-aiming antenna systems for vehicles that are cheap enough to do away with omnis there.)

Fixed wireless should be directional, clearly. That is more work and a touch more expensive, but again it is the sort of thing that can come down in price. One can even make fairly simple mildly directional antennas without moving parts if you have multiple elements and can switch among them by electronic means. Expensive today -- but in quantity 100 million, almost everything is cheap.

Very small devices like bluetooth dongles and the like will continue to have omnidirectional elements, but at low powers and high bands, mostly.

Omnis can also make sense if you legitimately have a giant audience. If you have millions of people tuning in to a broadcast, using high-power, omni signals like a modern TV station is not selfish, in fact it's efficient. It is an interesting challenge to work out what the audience threshold is -- in this case we do have a scarce piece of bandwidth. To show you are not selfish in using it, you would just show that your audience is at some percentile of size.

Omnidirectional antennas

Omnidirectional antennas (a misnomer, actually; they really should be called "antennas with 360 degree horizontal beamwidth) are not a menace. In fact, they are necessary to follow one of the precepts Brad advocates above: to use as little spectrum as possible and not hog it.

Many wireless ISPs use multiple sector antennas on multiple frequencies at their access points, unnecessarily congesting the spectrum. It is easy to demonstrate that the most efficient use of spectrum and the least interference in a point-to-multipoint system are achieved when each provider uses an omnidirectional antenna and a single channel, rather than multiple sectors and multiple channels.

Unfortunately, many of today's wireless ISPs use the multiple channel/multiple sector approach, with antenna gains and power levels that violate the FCC's Part 15 rules. Why? In part, because equipment vendors -- who get to sell them more equipment if they do this -- tell them to. Another reason is that no one is enforcing any requirement not to hog spectrum, so they just use it all. This approach backfires, however, when multiple providers must coexist -- especially on bands such as the 2.4 GHz ISM band. The 4 Color Theorem says that even if each WISP used a different channel on a directional channel pointed at each given area and the signal did not splatter into others, there STILL wouldn't be enough channels for interference to be avoided unless the number of available channels 4 times the number of WISPs serving the area. However, there's no "4 Color Theorem" for spectrum. So, if there are as many channels as there are WISPs (which can be achieved by using slightly narrower channels than standard Wi-Fi) you can have no interference between them.

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