The white space proceeding started in 2002 with a reasonably straight-forward premise. Every city has dozens of TV channels, with exceptional propagation characteristics, sitting empty. Why not use them for something? Low-power, unlicensed wireless devices operating on these unused channels – channels dubbed “white spaces” because they show up in white on a frequency map – could be deployed for a variety of uses, thereby increasing the efficient use of the spectrum. What’s not to like?
In theory, the concept looks great. But in practice, potential problems abound.
The primary concern, of course, is interference to other spectrum users. Each unlicensed device constitutes a potential source of interference if its operator happens to turn it on in the wrong place at the wrong time. And because the device is unlicensed, neither the FCC nor the victim of the interference will have any easy way of identifying the source of the interference.
The white space proceeding has thus been an effort to take advantage of the potential for wide-spread use of low-power, unlicensed devices on TV frequencies while protecting licensed users of those frequencies. Those licensed users include not only TV stations, but also wireless microphone users (a broad universe which includes not only TV and movie producers, but also churches, theaters and live music venues).
Back in 2002 the Commission kicked things off with a Notice of Inquiry relating to the possible use of portions of the TV band for unlicensed use. From that beginning, the Commission released a Notice of Proposed Rulemaking in 2004, which led to a First Report and Order in 2006, and then a Second Report and Order in 2008. The Commission’s deliberations were complicated by the fact that, throughout this time, the TV band was in the process of the digital transition, a process which wasn’t completed for full-power stations until June, 2009.
Meanwhile, a range of white space gadgets – now renamed “television band devices” (TVBDs) – was being developed by various proponents eager to get in on the ground floor of what many perceive to be a singular opportunity to create vast new and lucrative markets. In 2007, and again in 2008, the Commission tested out a number of prototype TVBDs in the field and in its lab. The goal was to see whether the devices could provide protection against interference.
The FCC advanced two basic approaches to interference protection. In one, the TVBD is capable of: (a) accurately identifying its own location (through GPS technology); and (b) cross-checking that location against a database of existing licensed spectrum users in that area. That cross-check process would preclude use of any frequency already licensed for use within a certain area. In the second approach, the TVBD is equipped with sensing capability allowing it to “sniff out” other uses of the TV band and automatically switch channels to avoid interference to such other uses.
Through several rounds of testing – testing which did not necessarily duplicate all real-world conditions – the “sniff out” technology did not fare particularly well. Still, the FCC concluded that the results demonstrated a “proof of concept”. In 2008 it adopted rules to authorize TVBDs under certain conditions. (As my colleague Mitchell Lazarus observed at the time, the Wright Brothers at Kitty Hawk also demonstrated the feasibility of powered, heavier-than-air, flight as a “proof of concept”, but it still took 30 more years for the check-in lines to form at O’Hare.)
The 2008 rules did not give an unequivocal green light to TVBDs, however. The rules imposed three constraints:
- Operation is flatly prohibited on certain channels, and in certain areas, and on some channels in some areas.
- Every TVBD must know where it is, and have a current list of open channels for that location, or else it must operate under the direct control of a TVBD having that information. (Manufacturers can bypass this rule by undertaking extra procedures; see below).
- Every TVBD must sense the spectrum for incumbents on the channel it is using.
The details were stringent. Device locations, for example, must be determined to within 50 meters, a requirement that only GPS can fulfill today. The catalog of available channels must be updated at least daily. Sensing must achieve a detection level of -114 dBm, equivalent to 0.004 trillionths of a watt – yet even this sensitivity could miss TV signals that are viewable with a good outdoor antenna.
Under the rules, TVBDs must be certified by the FCC before they can be marketed. To protect incumbent users of the TV band from millions of interference-causing renegade TVBDs, the Commission added extraordinary steps to the usual certification process. First, the manufacturer must test the device itself. Next, the Commission re-runs the tests, both in its lab and then again on the mean streets of America. Finally, the Commission seeks public comment on the TVBDs’ test results. Only after the successful conclusion of this stringent certification process would the Commission permit the importation and sale of any TVBD.
While the rules were technically adopted in 2008, they have not, for the most part, yet taken effect. Approval by the Office of Management and Budget is necessary before crucial elements of the new rules can be implemented. (Those crucial elements include the rules concerning the database of occupied channels and the procedures for approving sensing-only devices.) Also, to the extent that the protection system requires the existence of a comprehensive, accurate, frequently-updated database which TVBDs may check against, TVBDs can’t be rolled out until that database is in place. To date, that database is still on the drawing boards. (The Commission did invite proposals for the design and maintenance of such a database in November, 2009.)
Also, the Commission still has to resolve issues raised in 17 petitions seeking reconsideration of the 2008 rules. The petitioners include:
- broadcast-related interests who seek a return to square one, arguing that the record does not support any unlicensed devices on TV channels;
- LPTV stations that lack needed protection for still-ongoing analog operations;
- petitioners objecting to a great many specific technical rules, including emission limits, separation requirements, sensing levels, power levels for first-adjacent channels, special procedures for sensing-only devices, and fixed base station heights, among others;
- cable satellite TV providers that claim inadequate protection for headends and cable-ready TV sets; and
- those presenting other issues: real-time operation of the database that catalogs available TV channels; database information security and registration requirements; pending negotiations with the Mexican government; rejected proposals, such as licensed use of white space frequencies; and too many more to list here.
Additionally, an appeal of the rules is pending in the U.S. Court of Appeals for the D.C. Circuit, although that has been held in abeyance while the FCC works through the reconsiderations and database development.
So when the Commission rolls up its sleeves to tackle the white space proceeding at its September 23 meeting, it will theoretically be trying to (a) resolve the pending petitions for reconsideration and (b) get the database set up.
While those are already complex problems, they are further complicated by the brooding omnipresence that casts its shadow on everything the Commission does these days: the National Broadband Plan (NBP). The NBP expressly recommended that the Commission move forward with the white-spaces proceeding. That makes sense, since the NBP is all about increasing the efficient use of spectrum while encouraging technological innovation.
But the NBP also entails the possibility – if not substantial likelihood – that the FCC may reallocate up to 120 MHz of TV spectrum for broadband use. That in turn would require “repacking” of the remaining TV spectrum by moving existing TV stations from the reallocated spectrum to channels in the remaining TV band. The repacking process would almost certainly increase congestion in the TV band, which could reduce available white space and thus complicate the roll-out of white space devices.
There is much at stake in the highly technical, highly contentious white space proceeding. The Commission has thus far struggled to strike a workable balance between protection of incumbent licensees and the desire to unleash innovative TVBD services. Presumably that struggle continues. Just among ourselves, we think it might even continue beyond the September 23 meeting.