Fixed Microwave Group Makes Case for Putting More Spectrum to Work

Posted on June 10, 2012 by Mitchell Lazarus

Coalition asks FCC to adopt service rules at 41-42.5 GHz.

The Fixed Wireless Communications Coalition wants the FCC to adopt new rules for fixed microwave service in the 41-42.5 GHz band.

Almost every new service nowadays involves some degree of sharing, and this band is no exception. The 41-42 GHz segment is allocated not only to the Fixed Service – spectrum-speak for point-to-point microwave links – but also for Fixed Satellite Service downlinks, plus broadcast satellite and a few additional services. The adjacent 42-42.5 GHz region has no Fixed Satellite Service allocation, but does have the same allocations for the Fixed Service, broadcast satellite, and others. To date there has been no actual licensing in either part of the band.

Fixed Service users are willing to share the lower part of the band with satellite interests, according to the FWCC. It points out that sharing arrangements between the satellite and fixed microwave services are highly asymmetrical, tipped strongly in the satellite industry’s favor, so that sharing will have relatively little impact on satellite operations. In both parts of the band, though, the FWCC asks the FCC to follow through on an earlier proposal to delete the broadcast satellite allocation, on the ground that its continued presence would make sharing impractical.

Back in 2004, the FCC proposed service rules for the 42-42.5 GHz segment that would have relied on area-wide auctions, much like those at 39 GHz. The FCC never followed through. Now the FWCC urges it not to, pointing out that the 39 GHz band is severely underutilized, in large part because the auction-related renewal requirements, although intended to encourage rapid build-out, in actual practice have had the opposite effect of deterring construction. Instead, the FWCC favors link-by-link licensing with frequency coordination, a decades-old approach that has shown great success in the 11, 18, and 23 GHz bands, among others.

The 42 GHz spectrum is needed, says the FWCC, to help meet the rapidly growing demand for “backhaul” – i.e., the carriage of customers’ mobile data between cell towers and providers’ network facilities. This band, it adds, is especially well suited to handling short links in densely populated areas, which of course is where most of the mobile customers are.

The FCC has put the FWCC request on public notice. Comments are due no later than July 9, 2012 and reply comments are due within 15 days of the comments to which the reply comments are directed.
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FCC Deletes 2,456 Fixed Microwave Licenses

Posted on April 10, 2012 by Mitchell Lazarus

Action follows licensee’s failure to pay $430,000 in filing fees when seeking an extension of the construction deadlines.

The FCC has denied reconsideration of an order that terminated 2,456 fixed point-to-point microwave licenses.

Metropolitan Area Networks (MAN), obtained the licenses between January 2008 and March 2009. FCC rules require a link to become operational within 18 months of the license grant, or the license automatically terminates. For MAN, the deadlines fell between July 2009 and September 2010. But before the earliest of those dates, in June 2009, MAN filed applications to extend all of the deadlines until March 2011. It explained that the microwave links were intended to support TV “white space” systems, and that delays in the FCC’s finalizing of the white space rules required the extension.

Ordinarily an application to extend a microwave construction deadline must be accompanied by a filing fee, which at that time was $175. The total filing fees for all of MAN’s applications works out to almost $430,000. Understandably, MAN filed a simultaneous request for a waiver of all but one of the filing fees. But the FCC’s rules state that, when a fee waiver is sought, the filing fees to be waived must accompany the waiver request; if the waiver is granted, the fees will then be refunded. MAN paid the fee for one application, but not the others.   In July 2009, the FCC dismissed all but one of the extension requests for failure to pay the fee.

MAN filed a timely Petition for Reconsideration of the dismissal. No one opposed. Eighteen months later, when the FCC had not yet acted, the Fixed Wireless Communications Coalition asked it to delete the MAN licenses from the database, as they were hindering frequency coordination of other license applications. The FWCC argued that even if MAN prevailed on its reconsideration request, that would extend the construction date only through the preceding March, so that MAN would still be in default regardless of the outcome.

The Wireless Telecommunications Bureau has now denied MAN’s petition for reconsideration, and ordered the removal of its licenses from the database. As to all but one of the licenses, the FCC found the extension applications to be defective for failure to pay the filing fee. As to the single application for which the fee in fact was paid, the FCC found that MAN had offered insufficient grounds for the extension.

MAN can still ask the full Commission to review the Bureau’s decision. Its problem, though, is that even a reversal of the Bureau, and a grant of the extension request, would carry the licenses only through March 2011 – now more than a year in the past. So far as we can tell, MAN has no procedural path by which it might keep the licenses in force until it is ready to use them. It can, however, reapply for the same licenses when that time comes, although other applications filed in the meantime may have made some of the paths unavailable.

The guidance here for other microwave applicants is clear: the FCC’s 18-month construction deadline has teeth. Applying for licenses too soon can turn out to have expensive consequences.
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Effective Date Of New Fixed Point-to-Point Microwave Rules Set

Posted on July 19, 2010 by FHH Law

Last month we reported that the Commission had relaxed certain of its rules governing use of the 6 GHz and 23 GHz bands for fixed point-to-point microwave operations.  The rule changes responded to requests filed in 2007 and 2008 by the Fixed Wireless Communications Coalition. The FCC’s order in that proceeding has now been published in the Federal Register, which in turn sets the effective date for the new rules. That date is August 18, 2010.

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FCC Eases Rules For Fixed Point-to-Point Microwave Operations

Posted on June 12, 2010 by Mitchell Lazarus

Changes will allow faster implementation of service in 23 GHz and Upper 6 GHz bands.

Important changes to the FCC’s rules for fixed point-to-point microwave systems will give operators greater flexibility and allow faster initiation of service.

The first change affects the 6 GHz band. That band, the long-haul workhorse of fixed microwave, consists of two segments. The “Lower 6”, being shared with over 4,000 C-band satellite uplink earth stations, tends to be congested in populated areas. On the other hand, its maximum allowable bandwidth is relatively high, at 30 MHz. The less crowded “Upper 6” band has no earth stations, but limits channel bandwidth to only 10 MHz. An operator who needs 30 MHz, but cannot find room in the Lower 6, must request a waiver to use 30 MHz in the Upper 6. The FCC has issued about a thousand of these. But the need for a waiver rules out an immediate start of operation under the so-called conditional licensing rules, and triggers several weeks’ delay in getting these systems on the air. We wrote about these problems here.

The FCC has now amended its rules to add 30 MHz authorization to the Upper 6, thus obviating the need for waivers and allowing operators to use conditional licensing in order to commence service much more quickly.

The other change is in the 23 GHz band. Suitable for shorter distances than 6 GHz, this band is often ideal for transporting cell phone and mobile broadband signals to and from cell towers. But the band is shared with the federal government, which insists on reviewing non-federal applications on most frequencies. The need for that review bars conditional licensing and hence delays the start of operations. Conditional licensing is allowed on only four frequency pairs in the band.

The same FCC order linked above adds two more frequency pairs to the list of pairs eligible for conditional licensing (and hence immediate start-up) at 23 GHz.

Both rule changes were requested and advocated by the Fixed Wireless Communications Coalition.

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Microwave Group Scores Hat-Trick At FCC

Posted on June 7, 2010 by Mitchell Lazarus

Three rulemaking petitions go on public notice; comment and replies due in July.

The Fixed Wireless Communications Coalition, which represents fixed microwave users and manufacturers, achieved the rare feat of having three of its petitions for rulemaking appear on FCC public notice on the same day. The petitions ask the FCC to amend its rules:

Parties wishing to support or oppose the petitions must do so by July 5.  Reply comments are due on July 20.

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Microwave Group Asks FCC to Change Rules for 3650-3700 MHz

Posted on April 16, 2010 by Mitchell Lazarus

Potential users of band react to FCC refusal to settle interference dispute.

A plan to fix problems with the FCC’s novel licensing scheme in the 3650-3700 MHz band has come from the Fixed Wireless Communications Coalition (FWCC), a diverse group of fixed microwave users, providers, and manufacturers.

The 3650-3700 MHz band is unusual. In most shared bands, the rules require frequency coordination prior to licensing. A coordinator tries to slot each newcomer’s application into a frequency band where it will neither cause interference to incumbents, nor receive interference. The scheme protects those in first from those who arrive later, although the degree of protection varies with the type of service.

In the 3650-3700 MHz band, however, the FCC has established a kind of do-it-yourself frequency coordination on the fly. Before starting operation, each incoming user is expected to consult a database of other users, and to tailor the new station’s locations and parameters to avoid causing interference. The new location and parameters then go into the database for the guidance of those who come later. Licensees are expected to resolve any interference problems among themselves. The rules also require the use of “contention protocols” in the equipment to help prevent interference problems from arising in the first place.

It turns out the FCC means what it says about people working out problems on their own. A licensee in the band went to the FCC with a complaint that a newcomer had not bothered to check the database, was causing interference, and had not cooperated in fixing it. To the surprise of many, the FCC refused to intervene, reiterating that it would leave a resolution to the parties. We reported on the case back in December.

The FWCC expressed concern about this outcome, fearing that users with critical applications are likely to avoid the band, rather than risk interference over which they have no control. 

Part of the problem, it thinks, is that some of the key rules for the band use language that is merely advisory. The FWCC does not ask the FCC to play referee (a role the Commission plays in other contexts) – but it does want the rules reworded to make users’ responsibilities more clear.

Specifically, where the rule now says that licensees “should” consult the database, “should” try to avoid causing interference, and “are expected to” cooperate in resolving interference issues, the FWCC asks for an amendment to make these steps mandatory. This, the FWCC suggests, will preserve the speedy set-up and flexibility offered by the present rules, while improving the quality of service and giving providers better assurance that they can reliably meet customers’ needs.

Read the FWCC’s petition here.

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Microwave Group Muscles In On U.S. Spectrum

Posted on March 16, 2010 by Mitchell Lazarus

Coalition seeks to share federal frequencies for mobile broadband backhaul

The Fixed Wireless Communications Coalition (FWCC), on the same day that the FCC released its new National Broadband Plan, offers to solve one of the problems identified in the Plan.

We all know about the growth in mobile broadband, driven largely by people watching Internet TV and videos on their phones and laptops. The FCC’s efforts to find more spectrum for these applications – efforts that might involve even auctioning off TV channels – are getting a lot of attention. Less conspicuous is the parallel problem of “backhaul”: moving data back and forth between the network and the cell towers that communicate with all those mobile devices. Today most cell towers connect with copper wire that Alexander Graham Bell would recognize. It works fine for voice calls, but lacks sufficient capacity for broadband. At some locations optic fibers are an option. Other cell towers, though, especially at remote locations or in rugged terrain, are best reached by microwave radio links. And that requires . . . Raise your hands, class . . . anyone? Yes! More spectrum!

Fortunately backhaul signals ride best on higher frequencies than mobile broadband, so the two need not compete. The 4-10 GHz range is the backhaul sweet spot. Below that the antennas are too big; above, radio waves are impeded by rain.

The “fixed service” – an FCC category that includes backhaul – has allocations at 4 and 6 GHz. But their use is severely limited by satellite operations in the same bands, except for a satellite-free slice at 6 GHz. The only other “fixed” allocation below 10 GHz is a huge Government-only swath at 7125-8500 MHz.

With nowhere else to go, the FWCC has now asked the FCC to let non-Government users, including backhaul providers, share the 7125-8500 MHz band with the Government. Also involved in the decision will be the National Telecommunications and Information Administration (NTIA), a part of the Department of Commerce that manages spectrum for all U.S. Government agencies.

There is precedent for the idea. The fixed service band at 21.2-23.6 GHz has been shared between Government and private users for many years, with great success. The one problem, from the private users’ standpoint, is the delay in licensing on most frequencies due to the need for coordination with NTIA. To avert that delay in the 7125-8500 MHz band, the FWCC proposes a database of both Government and private usage so that private frequency coordinators can determine quickly whether a given link can be safely constructed.

It remains to be seen whether NTIA will go along. We all share so much with the Government, it seems only fair to ask the Government to share a little back. Except, of course, for the frequencies that control the Black Helicopters. They can keep those.

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Microwave Systems May Move Data Sooner -- And Slower

Posted on July 10, 2009 by Mitchell Lazarus

Expanded conditional license opportunities, greater tolerance for adaptive modulation in the works

Microwave radio serves as the nation's nervous system. (Microwave ovens, a different technology, take care of the stomach.) These radios operate through the ubiquitous sideways-facing dishes and domes on radio towers, water towers, and tall buildings. Their signals regulate the movements of railroad trains, control the electric grid and natural gas and oil pipelines, carry long-distance telephone calls and Internet traffic, transport TV programming to cable systems, send 911 messages to the local police station, deliver cell phone calls to the towers, tell the ATM your bank balance, and carry vast amounts of data that fuel ordinary businesses nationwide.

Many of these systems operate at availability levels in excess of 99.9999% (“six nines,” in industry parlance). This allows for outages adding up to no more than 30 seconds per year – not bad for systems that sit high up outdoors, exposed to the weather year round.

The FCC is considering three changes that would help improve the operation of these systems.

Conditional Licensing

To obtain a microwave license is time-consuming. The applicant must: (1) design the system; (2) go through frequency coordination, which limits harmful interference to other systems and warns the applicant about any harmful interference coming in; (3) file an application with the FCC; and (4) wait for the FCC to issue the license. 

But there is a shortcut. Under a procedure called “conditional licensing,” the applicant can flip the ON switch after step (3).  The system can thus provide service while the application wends its way through FCC processing, conditioned (hence the name) on having to shut off if the application is turned down. That rarely happens.

Demands for service can arise quickly, while the FCC – and we say this with the deepest affection – sometimes moves slowly. This makes conditional licensing an important tool for microwave service providers.

Two of the changes pending at the FCC are intended to make conditional licensing easier.

Of the several frequency bands allocated for microwave operations, the 6 GHz band is the long-haul workhorse. Low frequencies go farther; and in much of the country, 6 GHz is the lowest available. For links that must span tens of miles or more, 6 GHz is often the only choice.

The band has two segments, called the “Lower 6” and the “Upper 6,” which differ in two important ways. The Lower 6, shared with over four thousand C-band satellite uplink earth stations, tends to be more congested than the Upper 6, which has no earth stations. On the other hand, the Lower 6 allows microwave channels up to 30 MHz wide, while the Upper 6 maximum is only 10 MHz. An operator who needs 30 MHz, but cannot find room in the Lower 6, is not entirely out of luck. It can ask the FCC for a waiver to use 30 MHz in the Upper 6. Such waivers are usually granted. But an application that needs a waiver does not qualify for conditional licensing, and so the system cannot turn on until after several weeks of FCC processing.

The Fixed Wireless Communications Coalition (FWCC) asked the FCC to amend its rules to add 30 MHz authorization to the Upper 6.

The FWCC also had a request concerning the 23 GHz band. Suitable for shorter distances, this band is ideal for transporting cell phone and mobile Internet signals to and from cell towers. The catch (there always seems to be one) is the federal government, which shares the band. On the one hand, the government long ago set aside four channels in the band for conditional licensing. On the other hand, those are everyone’s first choice; they tend to be crowded, and are not available everywhere. An applicant for any other channel does not qualify for conditional licensing, and so cannot operate until the FCC grants the license. In addition to the usual FCC processing, a non-conditional 23 GHz application requires government sign-off, which further delays the grant.

The industry was pleased back in 2007 when the government freed up two additional channels for conditional licensing. But they were of no immediate benefit. The conditional-licensing channels are listed in the FCC rules, so adding two more requires a full-scale rulemaking proceeding. The FWCC formally requested that change in November 2007.

The FCC has now issued a Notice of Proposed Rulemaking to accommodate the FWCC’s requests in both the 6 GHz and 23 GHz bands. Comment and reply dates will be announced on publication in the Federal Register, which has not yet occurred. The language of the NPRM suggests that the FCC intends to adopt both of the requested rules, barring unexpected surprises. The docket is WT Docket No. 09-114.

On the 23 GHz item, the FCC took an additional and very welcome step: it granted a request from the FWCC for a waiver during the rulemaking. This makes the two additional channels available for conditional licensing now, even before the FCC has received and reviewed comments. In the unlikely event that the FCC declines to add the two channels to the rules, an applicant then operating on conditional authority would have to shut off until the license issues.

Adaptive Modulation

To a microwave signal, air is tricky stuff. Depending on the frequency band and atmospheric conditions, air can severely weaken a radio beam, or even bend it away from the receiver. “Fades,” as these conditions are called, can interrupt communications and make it harder to achieve “six nines” availability, or whatever the application needs. A modern microwave system automatically steps up the power to counter a fade. But power increases can only go so far, and if used to excess, can cause interference to other systems.

There is another approach, similar to one we use every day. When talking to someone in a noisy room, or shouting over a distance, people instinctively speak slowly. We know from experience that a slower message is more likely to get through. The same is also true of data carried via radio: slowing the data rate – the bits per second – makes communications more reliable. (This is embodied in Shannon’s Theorem, the central tenet of communications theory.) In addition to boosting the power, a microwave operator can combat an atmospheric fade by throttling back the data rate.

In a given system, the data rate depends primarily on the “modulation,” the technique used to impress payload data on the radio signal. A system that automatically changes to a slower modulation when needed is said to be using “adaptive modulation.”

But there is a catch, as usual. The FCC, seeking to ensure that spectrum is used efficiently, requires a microwave system to be capable of carrying certain amounts of data. In the 6 GHz band, for example, a channel 30 MHz wide must be able to carry at least 134.1 million bits per second. (For comparison, an Internet signal this fast would download an entire movie in about four minutes.) Adaptive modulation, to be useful, must sometimes drop the data rate below the specified minimum. Does that violate the FCC rules?

The FWCC, together with several microwave manufacturers and service providers, thinks not, and has asked the FCC to interpret the data-rate requirement in a way that allows the use of adaptive modulation. In a word, they want the FCC to treat the minimum in the rules as an average, not an instantaneous value. That would let a system occasionally drop below the minimum, for brief periods, so long as normal operation between fades meets the minimum, as does average operation over a period of time.

This makes sense. A system without adaptive modulation runs a greater risk of having a fade cut off communications altogether. That gives a data rate of zero, hardly efficient use of the spectrum. Worse, the system may need several minutes to resynchronize, during which critical payload communications cannot get through. Data transfer at a reduced rate is better than none at all.

The FCC has issued a public notice soliciting public input on the request posed by FWCC et al. Comments are due on July 27, and reply comments on August 11, in WT Docket No. 09-106.
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