Tokyo Forum; November 21, 2002
Community Wireless Networks and Regulatory Impact on Deployment in the United States
Tim Pozer (Founder, Bay Area Wireless Users Group)
This is a summary of Mr. Pozar's presentation at the Tokyo Forum on November 21, 2002.
I just want to cover a couple of things with two objectives. One is to show you the applications that we were trying to do with community wireless networking in the United State. I will give you a couple of examples; what people are doing, as well as some of the regulatory issues that we are having to deal with in deploying those networks.
Community Wireless Networks
So, the first thing I'd like to do is just define what the "community wireless network" is. We may be using it in a slightly different way. In fact, what we are trying to do is do much like what the original Internet was to have in co-operative network, that can be sharing work, resources and, actually, knowledge. In fact, the original Internet had no restriction on things like being able to publish, whereas we are running into that sort of things with asymmetrical bandwidth, port filtering,, non-static IP address assignment, etc., so that one cannot or is more limited to publish.
Community area network is also considered or known as a "free network." What I mean by " free network" is that once deployed, anybody can open a laptop and certainly communicate with anybody else within that cooperative network for free. Whether there is a monetary charge for going out the Internet is another issue. That is yet to be decided and that will probably be decided on a case by case basis for the community networks.
Community wireless network is also stretching the limits of the technology. 802.11 was originally designed as an office or home transmission medium. It was not necessarily designed to go tens of kilometers, but what community wireless people are doing is in fact doing that right now with antennas, amplifiers, things like that, hopefully keeping with the rules and regulations of the Federal Communications Commission.
Bay Area Wireless Regional Network
One definition that I'd like to show you is a group that I am working with, which is called "Bay Area Wireless Regional Network." What we are doing as an objective is to try to develop and document long range wireless technology, for third world countries, so that hey don't have to go out and spend tens of thousands of dollars for thing like radios by Western Multiplex.
We also want to be a wireless testbed to be able to do research, and we also want to be able to support public safety. We also want to be able to provide a "back-bone" to tie together other communities and groups and again respond to the loss of the bi-directional, expression on how the Internet is going. This is a real concern for a lot of people, particularly in the States.
There are different sizes of community wireless networks with a typical one, which is known as "hot spots" in the sense of the United State, necessarily a trade market in this sense. A friend of mime actually put up an access point connection, broadband connection, aimed it towards the cafe. So this way he was able to walk down, opened up a laptop, and be able to stay on the Internet at his favorite café. The café has no intention or no clue that this access point is actually there. That would be considered a hot spot.
Neighborhood Area Networks (NANs)
The next step up would be something like a "neighbor area network." Usually that is somebody who has gotten an access point, putting external antenna stayed on the top of their house or may be pointing out a window and try to cover one or more blocks with their broadband connection.
We will show you a couple of examples. New York City (NYC) Wireless, which is a community wireless group, is working with the City of New York to put access points around Bryant Park there. Bryant Park is actually a very well populated park there. There is a public library with the main branch of the public library for New York right there, and many people go over there, open up their laptops during the lunch and are able to stay connect to do things like Internet chat and such. This is all free.
This is a coverage map of actually my access points (PozarLAN) in San Francisco. You can see that covers a ittle bit more area. These are actually cross sections in the Sunset district of San Francisco. You can see this actually can cover about 20 or 30 blocks by just putting one access point there.
Metropolitan Sized Networks (MANs)
The next step up would be considered a Metropolitan Sized Network or a MAN. There are a number of organizations that are doing this. San Francisco Presidio, which is an area of San Francisco that used to be run by the Army has an organization called SFLAN. They are trying to cover this actually very nice parkland with 802.11 service.
There is another group called Seattle Wireless, where they are trying to get friends that have houses on hills - there are a lot of hills in Seattle - to put up access points, and not necessarily using current broadband, but doing things like "mesh networking," in other words, in order to get from one point to another in the city, you may have to hop thorough a number of different access points that are sitting on the top of the hills.
And then the group that I am working with, BAWRN, that is, Bay Area Wireless Regional Network, where we are using a backbone technology to cover multiple counties in the San Francisco Bay Area.
On the regulatory side of this, we actually are somewhat impeded, because to some degree unlicensed doesn't necessarily mean unencumbered. We do have certain responsibilities, and the FCC still has regulatory power over unlicensed devises such as 802.11.
The primary thing is that if you have even seen 802.11 device in the United Stated, there is a label on the back of it. And this is the paragraph but what I have underlined is actually the most critical thing here. "This device may not cause harmful interference, and this device must accept any interference received." This means that you have no priorities. You will not be able to have legal recourse to be able to address the interference you may encounter.
This actually touches on the biggest impediment to large investments in 802.11 deployment, due to the fact, again, you are not able to work anything out, if you have an interference, unless you can do it with handshake.
And the Impact of FCC regulation Part 15.5 is such that owners of wireless networks covered by 15:5 have no legal standing under FCC's rules to require interfering devices to shut down. One could deploy hundreds of thousands of dollars of wireless equipment that can be rendered ineffective if an other user of the band starts to transmit. Owners and operators of Part 15 networks must also shut down if they get interfered with by other users of the spectrum.
Other Users of 2.4 and 5 GHz
Part 15 devices are not the only users of 2.4 and 5 GHz. There are actually other licensed users that the band is shared with. Here is a list of all the other licensees and some unlicensees that actually share 2.4 and 5 GHz. I just want to point out that some of these people or organizations are very vocal with the FCC and have a lot of clout. They include, for instance, amateur radio community and also broadcast auxiliary.
Another point is Part 90. This is shared by public safety. Other users include an organization called NTIA, which monitors and regulates federal use of the bands, which also share the spectrum. We are also running to a problem, where we can interfere with ourselves due to the fact the there is a very limited amount of spectrum that can be used. In the United State there are only 11 channels. Since all the channels overlap each other, really there are only three clear channels, which do not overlap each other.
Another issue that we are running into and the FCC is taking a very active role lately in trying to prosecute is what is called "equipment certification". The FCC wants some responsible party for emissions that can cause interference. Typically this is the license holder. With unlicensed devices, the burden is on the manufacturer. Part 15 equipment is designed to be used by the general public. Equipment is certified as a "system" cannot be mixed and matched with other equipment. It is possible to re-certify equipment for our configuration.
Other issues include human exposure to radiation, where grass-roots, pseudo-scientific groups may be a factor. Also there are regulations on tower and antenna placement in housing tracks with height limits, etc. You may be limited by some broadband appropriate use policies (AUP).
In the future, there are some good and bad news. Fortunately, there are a number of standards and technologies that will help with interference, while some devices may contribute to interference such as RF lighting. Regulation may try to cripple long distance networking.
Who else may be trying to restrict unlicensed use of these bands? American Radio Relay League (ARRL) does not believe that the FCC has the legal right to allocate unlicensed spectrum and is challenging it. NTIA/IRAC has expressed some concern, but likely they have abandoned the channels except for high power applications. So there are other adjacent channel users, and anyone can affect you through the FCC's regulatory process.
Finally, I will say that community wireless networks can work with the following caveats. Deploying wireless network infrastructure based on un-licensed spectrum can be risky, as you have no rights or priorities. Coordination with other users is mandatory. A properly engineered and designed network will survive longer. Other issues can affect deployment like FCC Rules change or pressure to get the FCC to enforce. One needs to be active in watching and changing the FCC's Rules. Thank you.