> > Whitespaces devices should not need to rely on "circles on a map" as these > never quite reflect the reality of coverage. Hills, buildings, noise > levels > etc. never show up. I know, we use that method for some of our marketing. > It's a good estimate, but signal checks are still the only really > effective > mechanism for finding coverage zones. > >>>>> The TV contours we are talking about protecting are not just simple > circles on a map. They are based on the FCC criteria (for which I can not > quote off the top of my head, but it is published) that the broadcasters > must submit which then defines that particular TV station contour. I have > attached a map image for the state of Washington showing all the combined > analog and digital TV contours for ALL channels on file with the FCC. Many > of them overlap and some look like circles because if you do an RF > propagation at some of these sites using 50,000 watts you will get pretty > close to a circle result. These contours are part of the criteria we are > proposing to use in the goelocation database. Those contours are already > defined by the FCC and we are obligated to protect those licensed users > for > that particular area. It's not a random choice and it's certainly not just > a > circle drawn on a map. This comes from years of already established RF > engineering principles and rules. Some of those defined by the > International > Telecommunications Union (ITU) and thus by treaty, the FCC and US > government > are obligated to obey. You can further drill down on this type of data by > channel. I also attached images showing only the UHF contours and one for > only channels 31 and 32. Keep in mind these images include the current > analog stations. Once they go off the air this picture will change a great > deal. The maps are just meant to illustrate that this is a much more > complex > process than just drawing circles on a map. This also should help > illustrate > exactly what the white space spectrum potential can be nationwide when > looked at channel by channel.
Hmmmm. Interesting. From the looks of that map I should have several channels that will work well over the air. We're within what looks like coverage of at least 4 channels. Problem is, we don't get USABLE signal for more than one. You bring up a good point and I'm glad to learn this. I'll try to figure out some new phrasology. But my point isn't changed by it. *I* still have no TV coverage to speak of here so why not use the spectrum for broadband? > > The new devices should be held to a high standard for OOB emissions. I > think there should be two different standards. In one standard the > devices > aren't allowed to use the adjacent channels. But if a device is able to > limit it's OOB emissions sufficiently to protect the broadcasters the > adjacent channels should be allowed to be used. > > It's also time to start implementing some of the Spectrum Policy Task > Force's (SPTF) suggestions for improving the way spectrum is used. TV > broadcasting has remained basically static for what, 50+ years now? Same > channel sizes, same power output etc. With the change to DTV the > commission > should follow it's own advice and implement receiver standards instead of > only transmitter standards. Whitespaces devices AND TV sets/converters > should both be held to a minimum OOB rejection level of some kind. I > don't > know what the receive sensitivity is on the average TV set but based on > performance in my local area it's not very good these days. I think I've > run into less than 5 homes using over the air TV in the last 2 or 3 years. > When it became possible to get local channels via sat. signals everyone > moved to the better picture mechanisms that come with non broadcast > services. > >>>>> I don't know if you have tried off the air digital TV yet but you > should. First of all the current stations are running a fraction of their > concurrent analog station power levels. This is to protect adjacent market > analog stations on the same channels. Once February comes around they will > be turning those DTV stations up to maximum power. I have used a few > devices > with ATSC digital tuners in them and I can tell you there is one hell of a > difference in DTV over analog. It looks just like satellite quality when > it > works and if you compare it to the same analog broadcast, I have seen some > stations look perfect in DTV where I could hardly make out the picture in > analog mode. Another thing the DTV broadcasters have the option of doing > is > to multiplex up more than one programming channel on their broadcast in > digital. I have seen many stations run three or four separate channels on > their DTV carrier. That up to a 4 fold increase in spectrum efficiency. > You > may want to reconsider your point on that subject. I've heard that. But out here, there are NO DTV channels currently available. And we're not likely to cancel our satellite service now anyway. But those are issues that the FCC is paid to deal with. My job here is to tell them what my perfect world would look like. They have to decide how to ballance my perfect world with everyone else's perfect world so that in the end the public is the big winner. > > The SPTF also suggested that we start looking at time sharing as well as > spectrum sharing. I'd suggest that all AP's be required to sync transmit > cycles with each other, much the way that the Motorola Canopy product > currently does in 5 GHz. A second should be carved up into x time slots. > As VoIP calls need delays of 200ms or less I'd suggest that a second be > cut > up into at least 50 time slots. 100, maybe even 500 would likely be even > better. Each AP would be allowed to use all time slots as long as it > didn't > need to share space with another system. When another system needed to > use > the same channel (lets say we're operating in an area that TV channels and > adjacent channels have only left 4 available channels) each AP would split > the available time slots. > > This would, for all practical purposes, eliminate base station to base > station catastrophic interference like that from the self inflicted > interference article mentioned above. It would also place some level of > pressure on the manufacturers to create devices able to push as much data > as > possible down the pipe in as short of a time as possible. > > All Whitespaces devices should act as an intelligent network. All CPE > devices should sense and report to the AP's. The AP's should sense and be > aware of other AP's in the area. The AP's should then use the information > that they've gained to automatically set channels, power levels, time > slots > etc. on the fly and without operator intervention. > > All Whitespaces AP's should also issue owner contact information as well. > WiFi systems will tell scanners what channel they are on, what their name > is, MAC address, IP address etc. I think these new devices should NOT > have > the option of hiding. They should tell anyone that has the right tools to > look, what channels they are on and who owns them as well as how to > contact > that owner (via phone and/or email address). > > ATPC (automatic transmit power control) should also be built into > Whitespaces devices down to the transmission level. With base stations > dictating who will transmit at what time it should be reasonable to expect > the AP and client to only transmit at the power levels needed to maintain > stable connections based on receive signal levels at each device. With > ATPC > we should be able to run our systems at 5 to 10 dB of fade margin and > still > maintain great links. Time slot mechanisms that prevent system to system > competition for broadcast times would also help to limit the amount of > fade > margin that's needed. > > WISPA's proposal to give first in rights to those that build first is a > bad > idea. It effectively gives large companies or well funded venture firms a > nearly exclusive hold on the most lucrative markets. That will also > effectively stifle innovation and competition in a few short years. The > time slot mechanism allows for competition while also protecting existing > investments. I say this as the operator that was first in in most of my > current markets. On one hand I'd love to have been able to keep others > out > of my areas, as a successful entrepreneur I understand the value of > consumer > choice. > >>>>> WISPA's proposal does not give anyone first in rights. We were very > careful in our wording to not take that position and the use it or lose it > clause was put in there to try and minimize the spectrum campers from > doing > what you express (it has always been a concern of mine as well and that > point was always made clear to the committee). Use it or loose it still leaves the clause in there that if the first guy DOES use it to the point that there are no open channels, no one else can come in. > Nowhere does it state there > are first in rights. "These data points would include geographic coordinates, antenna beam width, transmitter power, antenna height, antenna polarization and antenna azimuth, which in turn could be used to calculate D/U (desired/undesired) protection ratios, geographic separation or any other defined measure of interference protection, as determined in this proceeding. After the data entry process, ULS would notify the registrant whether the proposed facilities are predicted to cause interference. If no interference to a primary licensee or a previously registered base station is predicted, the facilities could be placed in operation and, as described below, the Commission's database would be updated to show the new base station. If interference to a primary licensee is predicted, the registration would be rejected and the registrant could then propose alternative facilities. Although previously registered base stations would not be protected from interference from subsequent base stations, if interference to a previously registered base station is predicted, the prospective registrant could then propose alternative facilities so that neither party would suffer actual interference. " I'm not sure how else to interperate this section Brian. It clearly says that there can be no new stations that will interfere with an existing operator. Primary or "registered base station". > We have proposed that there are requirements for > notification of a new site to anyone else on that frequency registered in > the database and that there is record of such notification so that there > is > ample time for both parties to work out their technical details to avoid > interference to each other. After the 30 days they are still able to > construct even if there is no response from the other operators. If there > are interference issues the documentation will help the FCC deal with the > problem. This is one of those times when two operators could do things > like > share their time slot information to best occupy the spectrum. We did not > try and nail down the full technical details given the time constraints, > but > we felt the language was such that it would allow those details to be > worked > out later as part of any final order issued by the FCC. As they say, the devil is in the details and this is one that worries me quite a bit as written. Thanks for the comments. I'll work on changing this to reflect them. laters, marlon -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
