3.65GHz: Made for Independent ISPs
3.65GHz: Made for Independent ISPs
Tim Sanders has a think piece on the “lightly regulated” 3.650 GHz band. In a 30-page ruling (pdf), the FCC said that using restricted, contention-based protocols would “facilitate operation of the widest variety of broadband technologies with minimal risk of interference.”
The FCC recently blessed WiMAX gear in the bottom 25 MHz of the 50 MHz available in the 3.65 GHz range.
In almost all
respects, the FCC made no changes whatsoever to its prior rulings on the 3.65 GHz spectrum. What it did, however, was clarify the rules around its “contention protocol” requirement, which are extremely important for both WiMAX equipment vendors and carriers potentially using this spectrum. 
The spectrum is still non-exclusive, but does require base station registration and a filing fee for the spectrum by each provider, of which there could be many. This is close to the unlicensed-band approach, aside from the registration and fee. One operator described it to me as a “lightly regulated” band, which seems a very apt characterization.
This band is potentially very important, with a solid block of spectrum (50 MHz) that would carry even more bandwidth per MHz than the 2.5 GHz range. It also boasts a mid-range blend of power allotment (higher than unlicensed spectrum and lower than licensed spectrum) that has a lot of utility, especially for rural providers.
Specifically, this is 25 watts per 25 MHz of spectrum for fixed/portable use and 1 watt per 25 MHz of spectrum for mobile use. Non Line of Sight (NLOS) service at modest ranges should be possible with this power allotment.
This would free smaller companies in many locales from competing in a hugely expensive licensed spectrum auction. It should significantly help the deployment of broadband access in underserved areas, at least once equipment is available. Several operators have written me that they are already asking their providers when gear will be available.
Unrestricted gear could be used across all 50 MHz, and restricted gear could be used only in the lower 25 MHz of the band. WiMAX falls into the restricted category.
An example of an unrestricted protocol would be the CSMA/CA (carrier sense multiple access / collision avoidance) approach that Wi-Fi currently uses. Although the polling methods used by WiMAX are much more efficient, they only work within the context of WiMAX-to-WiMAX gear. Thus, the restriction to the lower 25 MHz is designed to prevent WiMAX gear from interfering with unrestricted protocols in the upper 25 MHz.
In my view, the FCC essentially segmented the band into WiMAX (or WiMAX-type gear) and Others.
Is this a good thing? Yes, especially in terms of time-to-market. Also, there were few, if any, gear types that were ready for the unrestricted protocol previously defined. This is a huge WiMAX win. We could potentially have gear certified by the FCC for this band next year.
Airspan Networks recently announced that it is launching a full portfolio of 3.65GHz WiMAX products for carrier and enterprise customers, following the FCC’s June 2007 Memorandum regarding 3.65GHz spectrum.
Airspan will offer two 3.65GHz WiMAX Base Station products, its carrier class HiperMAX base station and its MicroMAX base station which is expected to ship to customers in the fourth quarter of 2007.
Airspan also offers a full portfolio of 3.65GHz WiMAX subscriber terminals, including the indoor desktop EasyST (right), and outdoor ProST, both of which also support optional WiFi and VoIP extensions.
Airspan’s 3.65GHz U.S. WiMAX products also include a “Detect and Protect” contention protocol designed to operate in accordance with the FCC ruling and, subject to obtaining formal FCC certification, enable the use of both the restricted and unrestricted spectrum blocks.
Paul Senior, Airspan’s new CTO, commented, “We welcome the FCC release of the 3.65GHz spectrum as it will allow a broader adoption of WiMAX technology in the important global 3.6-3.8 GHz band. Airspan’s 3.65 GHz solutions enable operators who today do not have a licensed spectrum to build high value, low cost WiMAX networks in both urban and rural locations.