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Archive for the ‘White Spaces’ Category

White Spaces Geolocation Database

Friday, September 24th, 2010

For now, all White Spaces devices will use a geolocation database to avoid interfering with licensed spectrum users. The latest FCC Memorandum and Order on TV White Spaces says that it is still OK to have a device that uses spectrum sensing only (one that doesn’t consult a geolocation database for licensed spectrum users), but to get certified for sensing only, a device will have to satisfy the FCC’s Office of Engineering and Technology, then be approved by the Commissioners on a case-by-case basis.

So all the devices for the foreseeable future are going to use a geolocation database. But they will have spectrum-sensing capabilities too, in order to select the cleanest channel from the list of available channels provided by the database.

Fixed devices (access points) will normally have a wired Internet connection. Once a fixed device has figured out where it is, it can query the database over the Internet for a list of available channels. Then it can advertise itself on those channels.

Mobile devices (phones, laptops etc.) will normally have non-whitespace connections to the Internet too, for example Wi-Fi or cellular data. These devices can know where they are by GPS or some other location technology, and query the geolocation database over their non-whitespace connection. If a mobile device doesn’t have non-whitespace Internet connectivity, it can sit and wait until it senses a beacon from a fixed whitespace device, then query the geolocation database over the whitespace connection. There is a slight chance at this point that the mobile device is using a licensed frequency inside the licensee’s protected contour. This chance is mitigated because the contour includes a buffer zone, so a mobile device inside a protected contour should be beyond the range of any whitespace devices outside that contour. The interference will also be very brief, since when it gets the response from the database it will instantly switch to another channel.

Nine companies have proposed themselves as geolocation database providers. Here they are, linked to the proposals they filed with the FCC:

Here’s an example of what a protected contour looks like. Here’s an example database. Note that this database is not accurate yet.

Actually, a geolocation database is overkill for most cases. The bulk of the information is just a reformatting of data the FCC already publishes online; it’s only 37 megabytes compressed. It could be kept in the phone since it doesn’t change much; it is updated weekly.

The proposed database will be useful for those rare events where the number of wireless microphones needed is so large that it won’t fit into the spectrum reserved for microphones, though in this case spectrum sensing would probably suffice. In other words, the geolocation database is a heavyweight solution to a lightweight problem.

FCC to address White Spaces at September 23rd Meeting

Monday, September 13th, 2010

The agenda for the September 23rd FCC Commission Meeting lists:

TV White Spaces Second MO&O: A Second Memorandum Opinion and Order that will create opportunities for investment and innovation in advanced Wi-Fi technologies and a variety of broadband services by finalizing provisions for unlicensed wireless devices to operate in unused parts of TV spectrum.

Early discussion of White Spaces proposed that client devices would be responsible for finding vacant spectrum to use. This “spectrum sensing” or “detect and avoid” technology was sufficiently controversial that a consensus grew to supplement it with a geolocation database, where the client devices determine their location using GPS or other technologies, then consult a coverage database showing which frequencies are available at that location.

Among the Internet companies this consensus now appears to have evolved to eliminate the spectrum-sensing requirement for geolocation-enabled devices.

The Register says that this is because spectrum sensing doesn’t work.

The Associated Press predicts that the Order will go along with the Internet companies, and ditch the spectrum sensing requirement.

Some of the technology companies behind the white spaces are fighting a rearguard action, saying there are good reasons to retain spectrum sensing as an alternative to geolocation. The broadcasting industry (represented by the NAB and MSTV) want to require both. It will be interesting to see if the FCC leaves any spectrum sensing provisions in the Order.

Linley Report on Mobile Connectivity Chips Released

Saturday, February 28th, 2009

I have been working for some time on a report about mobile connectivity chips. This is an interesting market, one that is so hot that it is actually going to continue to grow in 2009 as the overall cell phone market declines by 10%.

The term “connectivity” denotes all the radios in a cell phone that are not cellular radios. There are a lot of them. The main ones are Bluetooth, FM radio, GPS and Wi-Fi. Others beginning to appear in handsets are TV and NFC. Further out in time are 60 GHz and White Spaces radios.

The cell phone market deals in massive volumes – about 1.2 billion handsets were sold in 2008. It also has some stringent requirements. The market demands chips that are small, cheap, battery-life conserving and easy to design-in. These considerations have driven chip vendors to combine multiple connectivity radios onto single chips. The first combo chips were Bluetooth plus FM. Then came Bluetooth plus FM plus Wi-Fi then most recently Bluetooth plus FM plus GPS.

Because the market is so big, the competition is intense. The 2008 leaders in Bluetooth were Broadcom and CSR; in Wi-Fi TI, ST-Ericsson and Marvell; in GPS TI and Infineon; and in FM ST-Ericsson and Silicon Labs.

These vendors are leap-frogging each other on performance and features. 2009 will see major changes in market share as some vendors fail to refresh their old product lines, others refresh their product lines but with inadequate products, and new entrants come in with better solutions.

FCC Approves White Spaces!

Wednesday, November 5th, 2008

This is incredible news. The FCC has done a wonderful thing, standing up to the broadcast TV lobby to benefit the people of America. What’s even better, four of the five commissioners are enthusiastically behind the decision:

It has the potential to improve wireless broadband connectivity and inspire an ever-widening array of new Internet based products and services for consumers. Consumers across the country will have access to devices and services that they may have only dreamed about before.

Some have called this new technology “Wi-Fi on steroids” and I hope they are right. Certainly, this new technology, taking advantage of the enhanced propagation characteristics of TV spectrum, should be of enormous benefit in solving the broadband deficit in many rural areas.

Today the Commission takes a critically important step towards managing the public’s spectrum to promote efficiency, and to encourage the development and availability of innovative devices and services.

While new broadband technologies are the most likely uses of these channels, the most exciting part about our action today is that we are creating the opportunity for an explosion of entrepreneurial brilliance. Our de-regulatory order will allow the market place to produce new devices and new applications that we can’t even imagine today.

The fifth commissioner, Deborah Taylor Tate, is only partly on board – she thinks some of this spectrum should be licensed, and she is concerned that not enough provision has been made for remediation in the event that interfering radios are deployed.

The FCC decision is a bold one – a more conservative positive decision would have been to approve a rural broadband access-only (802.22-style) use for now, but the commissioners went ahead and approved personal/portable use as well, which is what Google, Microsoft and numerous other computer and Internet industry companies have advocated.

The ruling imposed a geolocation requirement which will vastly increase the market for GPS silicon, though the trend in embedded GPS is to include GPS on the same die as other radios (like Bluetooth or cellular baseband) so whoever makes the White Spaces radio chips will probably be putting GPS on the same die by the second product generation.

The digital TV transition will open up the White Spaces spectrum in February 2009, but I will be very surprised if any white spaces consumer products appear in the market before 2010.

White Spaces Heat Up

Monday, October 27th, 2008

In my last post I alluded to the techniques by which the TV broadcast industry was resisting the FCC’s exploration of unlicensed use of unused spectrum in the TV bands. These techniques appear to have borne fruit. Representative John Dingell has written to the FCC with some questions that they need to answer before their November 4th meeting that has White Spaces on the agenda.

I hope that Rep. Dingell keeps an open mind on this issue, and studies it sufficiently deeply to form a balanced opinion. I hope the FCC commissioners stick to their guns and argue persuasively for their plans.

White Spaces Videos

Tuesday, October 21st, 2008

I found this “grass roots” video on Google’s Public Policy Blog. That blog also has some interesting posts on related issues by Richard Whitt and Vint Cerf.

Looking at this provoked me to go to YouTube and search for other White Spaces related videos. I was interested to find a coordinated (by Google) effort by the proponents of White Spaces, and on the other side basically nothing – just this incredibly lame video that takes 7 minutes to tell us that microphones are used in sports broadcasting (don’t waste your time watching more than a few seconds – it’s the same all the way through).

It’s odd that the main opponents of Whitespaces (NAB and MSTV) haven’t put rebuttal videos on YouTube yet, and even odder that they haven’t found a need to present any more thoughtful analyses of the issue, equivalent (but presumably opposite) to those of Chris Sacca or Tim Wu. Instead, I have the impression that their strategy rests on the two prongs of public fear-mongering and bare-knuckled political lobbying.

Green light for White Spaces

Wednesday, October 15th, 2008

The eagerly awaited White Spaces test report of the Office of Engineering and Technology of the FCC came out on Wednesday. The operational paragraph in the Executive Summary reads:

We are satisfied that spectrum sensing in combination with geo-location and database access techniques can be used to authorize equipment today under appropriate technical standards and that issues regarding future development and approval of any additional devices, including devices relying on sensing alone, can be addressed.

It is huge that the FCC leaves the door open to devices relying on sensing alone, because even Google had begun to back off from this idea.

As expected, the report is a little more enthusiastic about fixed wireless Internet access, the kind of use advocated by the IEEE 802.22 working group, than it is about the personal and portable use advocated by Microsoft and Google, among others:

It will… allow the development of new and innovative types of unlicensed devices that provide broadband data and other services for businesses and consumers without disrupting the incumbent television and other authorized services that operate in the TV bands. The Commission is considering whether to also allow “personal/portable” WSDs to operate in the TV spectrum.

I have been following the White Spaces saga for some time (click on the “White Spaces” tag below, and the links to the right of this column); it is a great idea in theory, and if it turns out to work as hoped, the concept could eventually be extended across much more spectrum, leading to a nirvana of effectively unlimited cheap wireless bandwidth.

The commissioners plan to discuss White Spaces at their November 4th meeting.

White Space update from TV Technology.com

Saturday, April 12th, 2008

Robin Berger of TVTechnology.com has written a good summary of the current (9th April 2008) state of White Spaces. She details the status of device testing at the OET and the recent proposal by Google on spectrum sensing, noting that Google’s embracing of geolocation puts them at odds with the rest of the Wireless Innovation Alliance.

She lists the main advocacy groups on each side of the issue, and summarizes their positions. Among the people apparently interviewed for the article are Stu Overby, Motorola’s senior director of Global Spectrum Strategy, Ed Thomas of the White Spaces Coalition and Ahren Hartman, Shure’s director of Platform Engineering. Also quoted in the article are David Donovan of the MSTV and statements from the NAB and the Broadway League, which is interested in wireless microphones.

In the discussion of the testing, the article covers the wireless microphone issue in depth, with an interview with Ahren Hartman.

Opposing Print Ads from White Spaces Advocates

Friday, April 11th, 2008

An April 8th 2007 article in PC Magazine gives some background on ads from the NAB and the WIA.

White Space update

Thursday, March 27th, 2008

The forthcoming transition to digital TV transmissions will free up about half the spectrum currently allocated to TV broadcasters. This freed-up spectrum was the subject of the FCC’s just-concluded 700MHz Auction, which yielded about $20 billion in license fees to the government. The fate of the other half of the TV spectrum, the part that will remain assigned to TV broadcasts after the digital transition, remains in contention.

This spectrum will be shared by licensed TV broadcast channels and wireless microphones, but even so much of it will remain mostly unused. These chunks of spectrum left idle by their licensees are called “White Spaces.” The advent of “spectrum sensing” radio technology means that it is now theoretically possible for transmitters to identify and use White Spaces without interfering with the licensed use of the spectrum.

The FCC has issued a Notice of Proposed Rulemaking and a First Report and Order to explore whether this is a good idea, and if so, how to handle it.

The potential users of the White Spaces have formed roughly two camps, those who see it best suited for fixed broadband access (similar to the first version of WiMAX), and those who see it as also suited for “personal/portable” applications (similar to Wi-Fi).

Google, along with Microsoft and some other computer industry companies, advocates the personal/portable use. The FCC’s Office of Engineering and Technology (OET) is currently lab-testing some devices from Microsoft and others to see if their spectrum-sensing capabilities are adequate to address the concerns of the broadcast industry, which fears that personal/portable use will cause interference.

Google filed an ex-parte letter with the FCC on March 24th, weighing in on the White Spaces issue. The letter is well worth reading. It concedes that in the introductory phases it makes sense to supplement spectrum sensing with other technologies, like geo-location databases and beacons. The letter asserts that these additional measures render moot the current squabble over a malfunction in the devices in the first round of FCC testing, and that the real-world data gathered in this introductory phase would give the FCC confidence ultimately to repeal the supplemental measures, and perhaps to extend open spectrum-sensing uses to the entire radio spectrum, leading to a nirvana of effectively unlimited bandwidth for everybody.

The kicker is in the penultimate paragraph, where Google recycles an earlier proposal it made for the 700MHz spectrum auction, suggesting a real-time ongoing “dynamic auction” of bandwidth. Google now suggests applying this dynamic auction idea to the white spaces:

For each available spectrum band, the licensee could bestow the right to transmit an amount of power for a unit of time, with the total amount of power in any location being limited to a specified cap. This cap would be enforced by measurements made by the communications devices. For channel capacity efficiency reasons, bands should be allocated in as large chunks as possible. The airwaves auction would be managed via the Internet by a central clearinghouse.

Current expectations are for spectrum-sensing use of the whites spaces to be unlicensed (free, like Wi-Fi). Now Google appears to be proposing “sub-licensed” rather than unlicensed spectrum use. The word “auction” implies that this could be a revenue producer for TV broadcast licensees, who received their licenses free from the government. This is a very different situation than the original context of the dynamic auction proposal, which applied to spectrum for which licensees paid $20 billion. Depending how it is implemented, it could fulfill the telcos’ dream of directly charging content providers for bandwidth on a consumer’s Internet access link, a dream that Google has opposed in the network neutrality wars. Google may ultimately regret opening the door to this one, even though it presumably sees itself cashing in as the ideal candidate to operate the “central clearinghouse.”

Update April 10th: Interesting related posts from Michael Marcus and Sascha Meinrath.