Congress to FCC: Now, Let's Do Something About 10 GHz

Some familiar faces take an alternative approach to trying to get the FCC to open up spectrum for wireless broadband.

Recently, we reported on bills introduced – actually, re-introduced, since proposals with the same language had died during the preceding Congressional session – by several reasonably high-profile Senators and Representatives. Their goal: requiring the FCC to study the possible use of the 5.9 GHz band for Wi-Fi use. Now the same crew is at it again, but they’re using a somewhat gentler approach. Rather than looking to require the Commission to do anything, this time they’re simply offering their support for the FCC’s efforts to “free up additional spectrum for wireless broadband use”. They don’t identify precisely which “efforts” they’re supporting, but they do happen to suggest that the Commission “explore potential sharing opportunities within the 10 GHz band”.

While the letter doesn’t say how this Congressional team happened to hit on the 10 GHz band, we’re guessing it wasn’t an accident.

As it turns out, back in May 2013, a company called Mimosa Networks filed a petition with the FCC asking it to start a rulemaking proceeding to make available additional spectrum for wireless broadband services. Where would that spectrum come from? Why, the 10.0-10.5 GHz band, of course. Mimosa suggested that additional spectrum is needed for wireless internet service providers (sometimes called “WISPs”) to provide long distance, high capacity links. These “backhaul” links form the middle portion of our internet connections, connecting points that collect “last mile” end user information to the Internet “backbone.” Backhaul is often transmitted over fiber (or legacy copper), but also it’s also transmitted wirelessly when the alternatives don’t make sense – for example, in rural areas, where wireless facilities are quicker and cheaper than fiber.

In its petition Mimosa asks for a fairly aggressive power level (55 dBW). That’s based on similar power levels (specified in Part 101 of the rules) for operations in the 10.7-11.7 GHz band. Mimosa also helpfully suggests ways to mitigate interference to radar uses – specifically, a method referred to as Dynamic Frequency Selection, which means that, before transmitting, the broadband system would have to first listen for the signals from other users.

The bad news for Mimosa is that the 10 GHz band is currently used by amateur radio (HAM) operators and amateur satellite services (amateur communications conducted via satellite). (It’s also used for both government and commercial radiolocation (a/k/a radar).) Longtime CommLawBlog readers will recall that amateur operators can be aggressive and persistent when it comes to protecting the spectrum turf they call home. Predictably, the amateurs opposed Mimosa’s proposal in full force. Whether or not as a result of that opposition, the Commission has taken no action on the proposal since the last comment was filed nine months ago.

Against that backdrop, what should arrive but the recent letter to Chairman Wheeler from six members of Congress, encouraging the FCC to be sure to check out the 10 GHz band as a possible means of “expanding Wi-Fi capabilities to bring Internet access to more Americans.” (For the record, the letter was signed by Senators Booker and Rubio and Representatives Matsui, Guthrie, Eshoo and Latta.) While their letter falls short of the considerably more aggressive approach that these Congresspeople took with respect to the 5.9 GHz band – i.e., introducing legislation that would require the FCC should to consider Wi-Fi sharing in that band – nonetheless a pattern appears to be emerging: when the private sectors says that more spectrum is needed for Wi-Fi, Congress will come knocking on the FCC’s door if the FCC doesn’t move quickly enough. It remains to be seen exactly how the Commission will react to this unsolicited advice from Congress. Check back here for updates.

Congress Steps Back Into Wi-Fi-Related Spectrum Fight

New bills would force the FCC to examine, on an expedited basis, possible Wi-Fi and other unlicensed use of 5.9 GHz band.

As a general rule, the FCC is in the driver’s seat when it comes to spectrum management in the U.S. But that doesn’t mean that Congress can’t, and won’t, occasionally engage in some aggressive backseat driving. And so it is that several members of Congress have reintroduced legislation – S.424 in the Senate, H.R.821 in the House – strongly suggesting the direction the FCC should take with respect to the 5.9 GHz band (i.e., 5850-5925 MHz). The bills would require the FCC to “provide additional unlicensed spectrum in the [5.9 GHz band] under technical rules suitable for the widespread commercial development of unlicensed operations in the band”, provided that the Commission first determines that such use won’t cause harmful interference to existing licensees of that band. The bills also provide detailed specifications, and an accelerated timetable, governing how the FCC must make that determination.

If this sounds familiar, that’s probably because an essentially identical proposal was introduced last year. No action was taken on it then, so it’s been reintroduced.

Under the detailed schedule set out in the bills, the FCC would have to:

  • solicit comments on proposals for “interference-mitigation” techniques and technologies (including potential rechannelization) that could permit the band to accommodate both existing users and “widespread commercial unlicensed operations”. For purposes of the bills, that latter term – which in recent years has been legislative shorthand for “Wi-Fi” – would include outdoor operations with at least one watt of transmitter output power, but would not require use of Dynamic Frequency Selection (i.e., the process in which the device automatically looks for, and then transmits on, available channels);
  • develop and implement a test plan for Wi-Fi use of the 5.9 GHz band. This would be done in cooperation with the National Telecommunications and Information Administration (NTIA) and the Department of Transportation (DOT). The bills helpfully provide a list of eight specific considerations that the FCC would have to address in this test process; and
  • based on the test results, adopt rules “suitable for the widespread commercial deployment” of Wi-Fi in the 5.9 GHz band (if the tests establish that such rules could be crafted so as not to cause interference to existing licensees in the band).

The bills lay out specific – and fast – time frames for each of these steps. The Commission would have to: invite preliminary comments within three months of the statute’s enactment; complete the test plan within six months of enactment; wrap up the tests within 15 months; and then adopt appropriate rules in light of the test results within 18 months of enactment.

The proposal, if adopted, would put Congress at odds with the automotive industry, which for more than a decade has been working to develop smart car technology (sometimes referred to broadly as Intelligent Transport). That technology would use the same 5.9 GHz spectrum band for “dedicated short range communications service” (DSRC), allowing cars to communicate wirelessly to prevent accidents. The auto industry and the DOT have been attempting to develop standards for vehicle-to-vehicle (V2V), or connected cars, technology. During the past few years, the DOT has been involved in demonstration projects to test V2V systems. Since it hasn’t yet adopted any regulations governing the commercial use of this technology, it’s safe to say that actual deployment will not be coming to your car anytime soon.

Intelligent Transport proponents are concerned that shared use of the 5.9 GHz band – particularly with Wi-Fi operations – could reduce the effectiveness of V2V operations. The notion of such sharing has been percolating at the FCC for at least a couple of years. The automotive industry, with DOT’s political support, has been fighting the idea of sharing the band with other potential users, including Wi-Fi, whom they view as a threat to V2V operations.

In contrast, Commissioners Michael O'Rielly and Jessica Rosenworcel recently put out an FCC blog post advocating for band-sharing between the two uses. As they see it, the safety considerations underlying V2V/DSRC operations should continue to be permitted and protected. But during the 15 years since such operations were first accorded their own spectrum, the DSRC has developed “slowly” while the demand for Wi-Fi and other unlicensed devices has “exploded”. Accordingly, Rosenworcel and O’Rielly are ready for “a compromise that allows both unlicensed and DSRC use” in the 5.9 GHz band.

Senators Rubio and Booker are sponsoring S.424 in the Senate, while Representatives Eshoo, Matsui and Latta are sponsoring H.R.821 in the House. These are not political unknowns, which ordinarily might mean that their legislation should get some consideration in Congress – although last year’s unsuccessful bills had the same sponsors. But even if this year’s model of the Wi-Fi Innovation Act, like its predecessor, fails to make it to the finish line, the fact that Rosenworcel and O’Rielly appear to be in agreement is, in and of itself, a noteworthy development. The votes in a number of recent high-profile Commission decisions have broken down along strict party lines. But since Rosenworcel is a Democrat and O’Rielly is a Republican, their common openness to the notion of some compromise that would give Wi-Fi access to the 5.9 GHz band suggests that there is likely no political roadblock at the FCC.

Congress Contemplates Cohabitation at 5.85-5.925 GHz

Bill would set timetable for unlicensed operation, deferred by FCC in April.

The crack electrical engineers and spectrum policy experts elected to the U.S. Congress are considering a bill called the Wi-Fi Innovation Act.

Readers may recall that the FCC proposed to add rules for Unlicensed National Information Infrastructure (U-NII) operation on 5.85-5.925 GHz at one watt output power. (U-NII overlaps with Wi-Fi and serves many of the same purposes.) The proposed use would share spectrum with “Dedicated Short Range Communications” (DSRC), authorized in 2004 for automatic communications among vehicles and between vehicles and roadside points, to facilitate safety and the movement of traffic. Although interest in DSRC remains high among vehicle manufacturers, widespread deployment does not appear imminent.

Some who support DSRC opposed the new U-NII rules in the 5.85-5.925 GHz band, fearing interference. The FCC’s First Report and Order in the proceeding did not resolve the issue, deferring action on it pending the completion of ongoing technical analyses.

If enacted, the Wi-Fi Innovation Act would take over the FCC’s deliberations. The FCC would have to: (a) consider “interference mitigation techniques and technologies” that would enable the proposed U-NII service at 5.85-5.925 GHz while protecting DSRC; (b) conduct tests of those technologies, and (c) adopt U-NII rules (or not) based on the outcome of those tests – all within two years.

In addition to imposing particular deadlines for FCC action, the bill would require actual interference testing. Parties to a proceeding often submit test results, and the FCC has sometimes done its own testing (in the TV white space proceeding, for example), but this is not part of the FCC’s usual routine.

An earlier version of the bill, from U-NII advocates in Silicon Valley, would have required the FCC to adopt U-NII rules even over DSRC objections. Then the DSRC folks stepped in. Their efforts led to the current version with required interference testing – a process that may take longer than would the FCC’s own processes, without congressional help.

The bill has the bipartisan support of some key members of Congress. But the present Congress, which will hold office until after the elections in November, has advanced very little legislation, and its upcoming calendar will be shortened by the election campaigns. There may be hearings on the bill in the fall, but prompt action beyond that is unlikely.

Users of 5.8 GHz unlicensed spectrum – you know who you are – may wish to keep an eye on the bill, as its passage could affect the availability of additional adjacent spectrum at relatively high power.

5 GHz Reply Date Extended

Reply comments in the proceeding on 5 GHz unlicensed operation are now due July 24.

In February we reported on an FCC proposal that would not only add new 5 GHz frequencies but also overhaul – maybe even simplify – a confusing stretch of the rules. One possible upshot would be the opening up of 195 MHz of spectrum for Wi-Fi-type operation.

Comments were filed on May 28. The FCC has extended the date for reply comments, originally June 24, to July 24.

Update: Comment Deadlines Set in U-NII 5 GHz Rulemaking

In February we reported on an FCC proposal that would not only add new 5 GHz frequencies but also overhaul – maybe even simplify – a particularly confusing stretch of the rules. One possible upshot would be the opening up of 195 MHz of spectrum for Wi-Fi-type operation.

The Notice of Proposed Rulemaking (NPRM) has now been published in the Federal Register which, as our regular readers know, establishes the relevant filing deadlines. Comments in response to the NPRM are due to be filed by May 28, 2013, and replies by June 24.

FCC Proposes to Simplify and Expand Unlicensed 5 GHz Use

Suggested rules would combine and harmonize the rules for various sub-bands, and open another 195 MHz for Wi-Fi-type operation

Blame it all on Congress. The Middle Class Tax Relief and Job Creation Act of 2012, best known for extending the since-expired payroll tax cuts, took just a few lines for that task, but continued on for another hundred pages of unrelated legislation. The statute has been good for CommLawBlog; we reported on incentive auctions, microwave issues, 911 implementation, and lots more. Now the FCC has responded to yet another mandate in the act: to expand unlicensed operations in the 5 GHz band.

But the FCC is doing more: it has issued a Notice of Proposed Rulemaking  (NPRM) that would not only add new 5 GHz frequencies but also overhaul and (we hope) simplify a particularly confusing stretch of the rules. We will touch on that first, and then take up the proposed expansion.

It is hard to overstate the importance of having enough unlicensed spectrum. The vast majority of radio transmitters in use today are unlicensed. We would be hard pressed to get along without Wi-Fi, Bluetooth, cordless phones, nursery monitors, automatic toll payment, automatic braking in cars, and myriad other such consumer conveniences. Industry as well relies on unlicensed communications and, increasingly, on unlicensed radar. Equally important, though less often mentioned, is the importance of unlicensed spectrum as a technology test bed. Licensed frequencies, if auctioned, are usually too expensive to risk on untried technology, while non-auctioned, site-licensed spectrum is governed by technical rules so restrictive as to preclude experimentation. Much innovation benefits from the technical flexibility inherent in the FCC’s unlicensed rules.

Updating Rules on the Present Bands

Unlicensed operations in the frequency range 5.15-5.825 today are governed by four sets of technical rules. Three are collected under the heading of “Unlicensed National Information Infrastructure Devices,” or U-NII, detailed in Section 15.407 in the FCC rulebook. The fourth comes under the “digital modulation” rule, in Section 15.247. Here is the breakdown:

Below 5.725 GHz, the U-NII rules are the only choice. The power limits are relatively low, and the need to avoid certain airport weather radars adds complication. The region above 5.725 GHz is popular because it offers the highest power for Wi-Fi standards a and n (and also the proposed standard ac). The band is a favorite of wireless Internet service providers, or WISPs, which offer Internet service via a roof antenna, mostly in regions not served by either broadband cable or telephone.

Before 2003, most manufacturers working above 5.725 GHz opted for the U-NII standards, which have no express limit on data speed, because Section 15.247 then limited speeds to about 11 megabits/second. But a rule change that year eliminated the limit in Section 15.247, and thus put the two sections on an equal footing for speed. Today Section 15.247 is the favorite because in fixed point-to-point applications it allows more focused antennas with no penalty in transmitter power, offers 125 MHz of bandwidth versus 100 MHz for U-NII, allows more power per megahertz, and has more relaxed limits for out-of-band emissions.

The FCC now proposes to harmonize the two rule sections. In some respects it suggests changing the U-NII provisions to match those in Section 15.247: namely, extending the upper bound on U-NII-3 by 25 MHz, to 5.85 GHz, and allowing the same power-per-megahertz as Section 15.247. In other respects, however, the harmonized rules would follow the U-NII provisions: a power penalty in fixed point-to-point applications for antenna gains above 23 dBi, and the more stringent U-NII limits on unwanted emissions.

A separate proposed harmonization would amend the rules for U-NII-1 at 5.15-5.25 GHz to more closely match those for U-NII-2 at 5.25-5.35 GHz in three respects: raise the power limit from 50 mW to 250 mW; raise the power-per-megahertz to match U-NII-2; and drop the limitation to indoor-only operation. As an alternative, also up for discussion, is raising the U-NII-1 power limits to U-NII-3 levels (1 watt), and again allowing outdoor operation. Neither proposal would require DFS or TPC in the U-NII-1 band.

The NPRM revisits the stubborn problem of U-NII-2 devices causing interference to airport weather radars operating at 5.6-5.65 GHz. Dynamic frequency selection (DFS) capability is required in the U-NII-2A and U-NII-2C bands specifically to protect those radars: the U-NII device must “listen” for the presence of a radar signal and, if found, move to a different frequency. Interference has persisted nonetheless, some from illegally operated U-NII devices that may lack DFS, but also from fully compliant systems.

Some interference to radars comes from users unlawfully changing the frequency of a certified device. This can result in a transmitter possibly overpowered for its band, with no DFS, operating on the same frequency as the radars. The FCC has found that some U-NII transmitters are easily modified in this respect. It proposes to require security safeguards to prevent such reprogramming, and/or the transmission of ID information to help locate offending units. It also asks for comment on these additional measures:

  • built-in geolocation capability in combination with database registration and access, so that units within a certain distance of a radar will automatically avoid its frequencies;
  • tighter limits on unwanted emissions to reduce interference from U-NII transmitters operating close by a radar frequency;
  • improved sensing capability; and
  • changes to certification test procedures to better assess sensing capability.

(Note to manufacturers and test labs: The above is only a rough summary. Please consult the proposed rules and measurement procedures in NPRM at pp. 39-45.)

Expanding into New Bands

As shown in the table above, the FCC is considering an expansion into 195 MHz of new U-NII spectrum. It hopes to find 120 MHz in the tentatively-named U-NII-2B band at 5.37-5.47 GHz, and another 95 MHz in the U-NII-4 band at 5.85-5.925 GHz. This would yield an unbroken sweep of 775 MHz, albeit subject to differing technical rules in the various sub-bands.

The problem, of course, is that both of the proposed new bands are occupied. The 5.37-5.47 GHz U-NII-2B band houses military and other government radars, weather radars (some used by broadcasters), NASA systems, unmanned aircraft, satellite observations of the planet, and border surveillance. At 5.85-5.925 GHz, U-NII-4, are more military and other government radars, automatic communications with and between vehicles, and a secondary amateur band.

U-NII, being an unlicensed service, will be required to protect licensed services, i.e., all of the above. We expect it will be a challenge to accomplish adequate protection to the satisfaction of the federal government (not to mention the amateur radio folks) while leaving enough technical elbow room for U-NII to be useful.

As a starting point for discussion, the FCC proposes:

  • U-NII-2B to operate under the same rules as the adjoining bands, U-NII-2A and U-NII-2C, providing 475 MHz of contiguous and consistently regulated spectrum; and
  • U-NII-4 to operate under the same rules as U-NII-3, with the same rules also applying to the 25 MHz in between. This would provide another 200 MHz that is contiguous and consistently regulated, at somewhat higher power.

The FCC seeks comment on whether DFS and TPC requirements should apply to U-NII-2B and U-NII-4, and if so, what the technical characteristics should be.

Manufacturers of future devices and present users of the proposed expansion bands should pay close attention. Reading between the lines, we have the sense that the FCC is tired of tinkering with these rules. The outcome of the proceeding may set the technical provisions for many years to come.

Comments and reply comments will be due 45 days and 75 days, respectively, after publication in the Federal Register. Watch this space (or subscribe) and we will let you know when that happens.