As the announcement at the left shows, the FCC website is announcing a 2 day workshop on “Spectrum Efficiency and Receivers”. The workshop was originally announced on February 24, 2012. The home page announcement has a link for each day, but they go to pages with the exact same content:

As part of the Commission’s efforts to enhance the use of spectrum for mobile broadband, the FCC Office of Engineering and Technology, in conjunction with the Wireless Telecommunications Bureau and the Office of Strategic Planning will host a workshop on "Spectrum Efficiency and Receiver Performance." The workshop will be held on Monday, March 12, 2012 and Tuesday, March 13, 2012, in the Commission Meeting Room at FCC Headquarters in Washington, DC.

The role of receivers in enabling access to spectrum for new services implicates federal stakeholders, as well as the private sector. Receiver performance issues have often arisen as a conflict between legacy stakeholders and new entrants where deployment of new technologies and services threatens to adversely impact an incumbent or place restrictions on the new entrant. Past examples include interference issues between new cellular radio systems and public safety radio systems, satellite digital radio systems and proposed terrestrial data services, unlicensed WiFi systems and FAA weather radar systems, and ancillary terrestrial service on mobile satellite spectrum and GPS. The resolution of such matters has historically required a public process involving regulators, stakeholders and other parties. Because such discussions sometime begin upon the introduction of a new service or technology, full deployment of such new services could be hindered. New approaches to spectrum management focusing on spectrum efficiency and receiver performance may enable more assured deployment of new services and reduce the necessity for the involvement of regulators.

This two-day workshop will discuss the characteristics of receivers and how their performance can affect the efficient use of spectrum and opportunities for the creation of new services. Key topics will include current practices for receiver design, case studies involving interference due to receiver characteristics, and approaches for promoting interference avoidance and efficient use of spectrum, given the current receiver base and potential future deployments. The workshop will include perspectives from licensees, equipment manufacturers, component providers, and other interested parties.

Apparently there will be panels of speakers, but they have not been announced. Nor has any sort of agenda beyond the above been announced.

(I was surprised by the mention of “unlicensed WiFi systems and FAA weather radar systems” as I have previously written this appears NOT to be a receiver problem, but rather an SDR security issue for the unlicensed cognitive radio systems. Oddly, my September 2011 appeal of an initial redaction of a FOIA request has never been acted on by FCC/OGC. I believe the requested document with fewer redactions would confirm the real nature of the TDWR problem. Motorola is fighting the release of the document with fewer redactions in a “reverse FOIA” action.)

My suspicion is that there is a major coordination problem among the various power that be within FCC on both the agenda and the speakers, probably in their attempt to pacify various industry sectors who have their own view of the issue. Perhaps there is an NTIA problem also.

NTIA has classically been in favor of receiver standards, claiming they have them for federal systems. (Mostly true.) However, NTIA has been unwilling to pressure FAA into adopting 20 year old ICAO Instrument Landing System receiver immunity standards that are used around the world and has been strangely silent on the issue of GPS receiver standards.

In any case, it seems rather strange to have a 2 day workshop with no published agenda 3 working days before it starts.

UPDATE

The afternoon of March 9, the agenda was released.

UPDATE 2

The Powerpoint presentations used are available now on the (ever chaotic) FCC website.

Here are the videos of the 2 days:

Tags: Receiver standards, Spectrum policy

The cellular industry has severe mood swings with respect to unlicensed spectrum. Presumably the cellular industry is the power behind the recent Spectrum Innovation Act of 2011’s Section 104, which, if adopted, would require an “unlicensed auction” for all new unlicensed spectrum. No one from any industry has spoken publicly in favor of this concept.

However, Thomas M. Lenard, president of the Technology Policy Institute has tried to explain its merits in a post entitled “Use the market to allocate spectrum” in another blog. While the intent of Mr. Lenard appears to be limited to spectrum related to the proposed incentive auction, the language in Section 104 would have made any future new unlicensed spectrum nearly impractical regardless whether it was exclusive unlicensed spectrum in the incentive auction spectrum or even secondary/“junk” spectrum use such as for Wi-Fi or U-NII.

But despite this industry “dissing” of unlicensed spectrum and the dogma that only exclusively licensed spectrum is efficient, the cellular industry has embraced unlicensed quietly in other contexts. In October Fierce Wireless reported,

AT&T said the number of connections to its Wi-Fi network nearly tripled year-over-year in the third quarter to 301.9 million. AT&T also said that the amount of data on its Wi-Fi network in the quarter more than doubled from the year-ago period.

The statistics reflect not only AT&T's growing use of Wi-Fi offloading for its cellular networks but also the wider trend within the industry to use Wi-Fi as a tool to manage mobile data traffic. Indeed, AT&T said that users are now making around 100 million Wi-Fi connections per month, more than the total number of connections made in all of 2009 and five times the total number of connections made in 2008. For now at least, neither AT&T nor any other U.S carrier counts Wi-Fi usage toward a subscriber's monthly data allotment.

AT&T's Wi-Fi hotspots now number 29,000 across the country, and AT&T said hotel locations account for approximately 40 percent of the carrier's total Wi-Fi network traffic.

Yesterday, the usually reliable GigaOM reported

In a sure sign that the cellular industry is getting serious about Wi-Fi, telecom networking giant Ericsson is buying BelAir Networks, adding its high-performance outdoor hotspot technology to its portfolio, sources told GigaOM. The deal could signal a big shift in the mindset of the big wireless vendors, which have always favored their own specialized and expensive cellular technologies to meet growing mobile data demand rather than more generic but much cheaper Wi-Fi technology. ...

As smartphone data usage explodes, consumers have begun turning to home, office and public Wi-Fi to bring their handsets online, taking advantage of fast speeds while bypassing the data caps on their mobile plans. There are some exceptions, such as AT&T, but most U.S. mobile operators have been reluctant to incorporate Wi-Fi directly into their networks, preferring instead to keep customers on their 3G and 4G networks, where they can collect data revenues and maintain control of the network connection. With big vendors like Ericsson on board, though, that attitude could be changing.

While your blogger was responsible for bringing a total of 5234.5 MHz into unlicensed use through the proposals he drafted and the decisions he helped draft in Dockets 81-413 and 94-124, he does not see unlicensed as a panacea for all the world’s spectrum problems. Exclusive licensed and unlicensed band both have positive points and both contribute towards an efficient telecom infrastructure.

It is unfortunate that many on both sides view the choice between licensed and unlicensed as a zero sum game with respect to the long term interests of the cellular industry. The continuing industry interest in Wi-Fi shows that the truth is more complex.

Tags: spectrum policy , unlicensed policy

In the April 2011 issue of IEEE Wireless Communications magazine is an article by your blogger with the above title. It explores an idea that first came up during the ill fated AWS-3 deliberations: are there special cases where the “hidden node problem” can be solved?

The hidden node problem refers to the problem of protecting receivers from interference in a cognitive radio system when you can’t explicitly detect the receiver’s presence. This is the crux of the TV whitespace problem since TV receivers can not announce their presence. (In that case the use of cognitive radio detectors 20+ dB more sensitive than TV receivers can be used to solve the problem although FCC chose the more conservative approach of geolocation for initial implementation.)

The instant article considers the case of a full duplex mobile transmitter with known frequency offset, as in the case of the ubiquitous cellphone. It points out that in this case the hidden node is no longer “hidden” since it can be readily detected at short distances by the uplink signal and that the receiver frequency can also be calculated by adding the offset to the detected uplink frequency.

This is a special case of Preston Marshall’s general observation that while cognitive radios are best known for finding empty spectrum that can be used without cochannel interference, if you know the location and characteristics of nearby receivers you can also select frequencies that will not result in interference from adjacent channel or intermodulation mechanisms in receivers with limited rejection capability. Pres points out that receiver ejection capability is generally expensive because it requires on precise analog components, whereas cognitive radio technology is mostly digital with little marginal cost in the long run.

In the AWS-3 proceeding, T-Mobile, the adjacent channel licensee in most places, claimed that adjacent channel interference to their FDD downlink was inevitable if the adjacent AWS-3 were used for either uplinks or TDD. Since we now know that T-Mobile was “on the auction block” during this deliberation, they had every incentive to maximize their sale value by using a massive legal effort for both trying to stop a new entrant and removing any risk of interference from concerns of potential purchasers. One of the parties in the AWS-3 proceeding mentioned a variant of virtual guardbands in comments, but this was promptly dismissed by the cellular mainstream as speculative.

But while there might be some slight question of how well TV whitespace devices can detect a TV signal from 50 miles away that provides marginal reception to TV sets using antennas near the devices, detecting a cellphone uplink signal nearby - the only place where adjacent channel or intermodulation interference is a threat - is trivial by comparison.

Industry loves to demand guardbands: it is a proven technology to prevent interference and also limits competition. But guardbands also have a real cost in our spectrum dependent economy that is always searching for more spectrum. Virtual guardbands can be a realistic way to use today’s technology to avoid interference while allowing more intense spectrum use at the boundaries of FDD bands.

FCC has never resolved the AWS-3 issue, they just told M2Z Networks that no answer was coming soon. AWS-3 continues to lie fallow as we beat the bushes to find the 500 MHz of new spectrum demanded by the National Broadband Plan. - there are no easy answers. Maybe with technologies such as virtual guardbands we can put AWS-3 to use serving society and the economy. With AT&T and T-Mobile now before the Commission begging for permission to merge, maybe they can more more flexible on the AWS-3 issue as a merger condition.

Tags: virtual guard band, DSA, Cognitive radio, Dynamic spectrum access

IEEE-USA is the policy arm of the Institute of Electrical and Electronics Engineers. It advances the public good and promotes the careers and public policy interests of 210,000 engineering, computing and technology professionals who are U.S. members of IEEE and this week sent a letter to FCC on the implementation of Section 7 of the Communications Act of 1934.

Since the passage of Section 7 in 1983 in response to the Commission’s endless delay in resolving issues about an innovative narrowband land mobile technology, it has carefully tried to avoid ever mentioning the existence of this provision in both decisions and publications. Section 7 is not a perfect piece of legislation. It has an explicit deadline, yet doesn’t state exactly what has to be done within that period.

The IEEE-USA letter points out that the Commission does have explicit guidelines for review of pending mergers and forbearance petitions pursuant to Section 10(c) of the Act that both give nominal time schedules. However, there is no analogous guidance on Section 7 issues.

The letter also pointed to recent White House initiatives to speed up patent review to expedite innovation:

We believe that FCC might wish to emulate the White House’s recent Startup America initiative “to dramatically increase the prevalence and success of America’s entrepreneurs.” Under part of this program the Patent and Trademark Office (PTO) will offer an Enhanced Examination Timing Control Initiative “to give innovators more control over the application processing and support a more efficient market for innovation.” For wireless innovations subject to non- routine FCC approvals, FCC deliberations determine if and when diffusion, and thus positive cash flow, is possible. In contrast, the improved and more timely PTO decisions only scope the level of intellectual property protection were these cash flows possible. We urge the FCC to examine this PTO initiative and consider offering to entrepreneurs parallel programs to resolve policy deliberations on a faster, more predictable basis.

FCC has a poor track record in responding to this type of suggestion. Let’s hope they are more attentive this time. If others with like views tell Chmn. Genachowski their views, more may happen.

vox populi, vox dei

Tags: 47 USC 157, Wireless innovation