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Mobile WiMax’s inclusion in a global wireless broadband standard means that it can be used over standard bands approved for this purpose: IMT-2000 is a set of five radio standards linked to other elements that have been approved by many different authorities for use over advanced wireless bands in their various countries and regions. The two most popular are W-CDMA (GSM 3G) and CDMA2000 (CDMA 3G). By gaining ITU approval for mobile WiMax (really, 802.16 in this context), this dramatically increases the odds that it can be deployed more widely by not requiring special approval or specific bands. It also provides mobile WiMax as a migration possibility for carriers that haven’t yet deployed 3G.
Early mobile WiMax profiles from the WiMax Forum cover 2.3 GHz, 2.5 GHz, and 3.5 GHz, the most common currently available bands worldwide. (5.4 and 5.8 GHz mobile WiMax isn’t covered by approved profiles, but the same technology may be used on those bands as on the profiled bands.)
The news was made public on a mailing list for those involved with IEEE 802.16 by Roger Marks, the working group’s chair.
As might be recalled, a good hunk of the 2.5 GHz that Clearwire and Sprint Nextel “own” is sublet from academic and other institutions which originally received allocations for distance learning, among other purposes: Ah for the days when sweet, prime spectrum was given away without a purpose being set in stone. Congress allowed the institutions that were granted these licenses to sell them as a sort of non-auction backdoor that’s resulted in the holdings primarily in the hands of Sprint Nextel and Clearwire today.
Many institutions apparently forgot they had the spectrum, and has the value has become known have filed renewal notices, both on time and late. Apparently, some lapsed licenses if renewed would impinge on other coverage areas, which doesn’t exactly make sense to me since 2.5 GHz licenses were assigned on a frequency and geographically divided basis. There must have been some multiple licenses in the same areas who were supposed to work out conflicts.
Clearwire, which has more of these licenses, Marketwatch reports, wants the expired licenses renewed, because, they say, that would speed the way to getting that spectrum in use. Sprint not so much, as they apparently think they have an advantage in their spectrum portfolio. Clearwire and Sprint will build out a network jointly, if the government approves, but I imagine revenue splits and roaming may be based on coverage areas. The less Clearwire has, the more Sprint can sell to what would have been Clearwire customers.
This article also notes that a lawsuit against the Peralta Community College District was settled with Peralta receiving more fees than originally agreed to. Peralta had alleged a side agreement with Clearwire that would have provided more than the main agreement promised. The suit was filed in mid-2006. The license was their only viable San Francisco Bay Area spectrum at the time.
The FCC, after nearly two years, has affirmed its plan to allow overlapping uses of the 3.650 GHz band: The agency has reserved 50 MHz for a special kind of licensed use that will make it possible to run reliable high-signal-strength systems from fixed base stations using WiMax or—an import or—any other standard or technology that conforms to what sound like fairly broad rules. The band will allow 20 watts of transmit power versus a maximum of 1 watt for an omnidirectional antenna with Wi-Fi and like systems in 2.4 GHz and some of 5 GHz.
The licensing require is just a bare minimum. There will be no restriction on the number of licensees, and licensees will be required to register themselves and how they’re using the band in their area. The users of the band will have to coordinate among themselves to avoid interference and system problems. Failing that, the FCC could step in. But no licensee under this regime will have any priority rights over any other.
It’s a significant departure from the Part 15 rules that govern unlicensed Wi-Fi and other devices in 2.4 GHz and 5 GHz, in which every device is required to accept interference without complaint, but not generate too much interference. The 2.4 GHz band in particular is a problem because there are many competing uses of the band, including licensed users that do have priority (amateur radio operators among others).
The band isn’t completely clear, however. Earth receiving stations for satellite systems will have priority over new uses, and they will have broad exclusion zones that will prevent this band from being broadly used in urban areas, especially on the coasts. Wireless ISPs and others who can, however, negotiate with earth station operators and come up with solutions that let them operate in the band.
Initially, therefore, rural areas will see much simpler use—with potentially no overlapping wireless ISPs, even—and, Harold Feld argues, so will municipalities. The band is perfect for backhaul and network links for a muni network, and cities are in good positions to negotiate with the existing licenseholders—they’re on the hook if something goes wrong.
The lower 25 MHz of the band will require scheduling of time slots among competing devices in the same airspace; the upper 25 MHz entire band will use open contention rules similar to those in Wi-Fi (listen to see if anyone’s talking, and then start talking if they’re not). That’s WiMax rules for the lower band, more or less, and Wi-Fi rules for the whole thing. (Note: I had originally stated that only the 25 MHz top half of the band would allow contention rules; not the case. See the comment from Harold Feld below.)
I’ve linked to Harold Feld’s analysis. Feld works for the Media Access Project, a non-profit that’s interested in expanding the number of voices that get heard by influencing media ownership, telecom, and spectrum policy. So he has a horse in this race. But his description is detailed and tells you who has won and who has lost (no one, really) in the FCC’s decision.
Meanwhile, Ubiquiti already has a piece of gear ready to go—it’s designed for either 3.5 GHz (a more broadly available worldwide chunk of spectrum) and 3.65 GHz with contention.
XM Radio revealed that many of its ground transmitters are out of compliance: The company told the FCC that 221 repeaters (which are really very little different from terrestrial radio stations) were operating above their power levels and 19 repeaters were using out-of-band frequencies. The ground stations are a critical, often-overlooked part of XM and Sirius’s coverage requirements for their radio services, offering a boost to signal strength in areas where the satellite signal can’t penetrate, mostly in urban areas.
Because XM’s licenses adjoin 2.3 GHz licenses that will be used for services such as WiMax, there’s apparently some real anger, as expressed in this article. This article says that there’s little deployed in 2.3 GHz, but my sources say there aren’t a lot of users, but there are a number of deployments.
The FCC is evaluating what its response should. An industry trade group wants a full enforcement action to bring XM into compliance.
There are some interesting discussions going on across the blogosphere surrounding software defined radio and regulations: Sascha Meinrath has a couple of warnings. The first is that if a few of the most promising open projects don’t get some sustainable funding, the big companies will corner the market with proprietary solutions. Her second warning is that if regulators around the world don’t recognize the potential of SDR and accommodate for it, people will do it anyway and regulators won’t be able to stop them. The result is what she calls “pirate radio on steroids,” where load of people will be using SDR products that will become available to make at very low costs and that will be basically impossible for regulators to track down and stop. The solution to this problem, she argues, is for regulators to make available enough unlicensed spectrum that SDR fans won’t need to encroach on licensed bands.
Sascha’s piece is interesting next to a piece written by Guy Kewney. He also argues that if regulators don’t deal with software defined radios, people will use them anyway and there won’t be anything the regulators can do to control them. He’s confused a couple of issues here and possibly gotten some facts wrong, but basically he also suggests that Intel is working hard on building software defined radios into chips as a way to accommodate for the different spectrum bands likely to be used for WiMax around the globe. Where Kewney seems to get confused is where he writes about Intel’s efforts to make 2.5 GHz a worldwide standard. If there were a clean worldwide band, software defined radios would be unnecessary. It’s more likely that Intel would be working with regulators to make sure they’ll allow software defined radios so that Intel could easily accommodate for the different spectrum availabilities around the globe.
Software defined radio has huge potential but I fear that Sascha’s first warning may come true. Already, engineers have been talking about and working on software defined radio for many years, and it’s only just begun to get a mention by regulators. The longer regulators take to open up to the idea, the greater the possibility that some huge company will corner the market, slowing down or stopping the great innovative potential of the concept.
As a condition of approval of the Sprint/Nextel merger, the FCC set some broadband wireless goals for the new company: Within four years of the merger, the companies must be serving 15 million people using their combined 2.5 GHz assets. That figure must double within six years. The combined companies control less then half of the 2.5 GHz band and both have actively trialed equipment for networks that could be deployed in the spectrum. As the author of this story notes, while it’s great to see some pressure on these companies to launch, the FCC has been known to forget requirements on telcos.
Some are saying that the FCC’s decision to stop requiring DSL operators to open their networks to ISPs may be good news for wireless broadband: This is the end of the road for most ISPs. However, it’s also a big opportunity for broadband wireless equipment vendors. Essentially the only way to be an ISP in the future will be to have your own facilities and wireless is the most cost effective way to do that. Dana Blankenhorn suggests wireless ISPs tout the fact that they’re able to totally bypass the telcos as a way to win customers eager to take their business away from the incumbents.
This is a bit of a side note but also relevant. Wireless networks need backhaul. Wireless operators can lease lines from telcos, lay their own fiber or use point to point wireless links. They can even use LMDS spectrum. That’s right, you read correctly, the long forgotten LMDS spectrum. First Avenue Networks has consolidated a bunch of the LMDS spectrum and is currently doing a lot of backhaul for cellular companies. Wireless ISPs could also lease bandwidth from an operator like First Avenue for backhaul and an executive at the company says it is looking at the WiMax opportunity.