08.20.08

Google: The Kid that Gets Your Side in Trouble

Posted in TV Bands, white space at 10:16 am by JamesNeel

Google has started a propaganda promotional campaign to get public opinion behind opening up the TV Band’s white spaces for unlicensed devices. The website is here where you can sign a petition urging the FCC to open make unassigned TV bands officially unlicensed, if you’re so inclined (I’m not yet at this moment).

According to Fierce Wireless

Google is hoping public pressure will help it in its campaign to get the FCC to make white space spectrum available for unlicensed wireless Internet devices. The company today launched a campaign called “Free the Airwaves” that will target rural and Native American communities across the country that have inconsistent or no Internet connections.

Google has been lobbying to get this spectrum, which sits between the airwaves currently licensed to TV broadcasters, to be used to develop new mobile communications devices. However, the initiative has raised the ire of the National Association of Broadcasters, which argues that white-space devices may interfere with existing television broadcasts.

Since broadband over TV bands is already authorized for rural spaces, but for fixed devices (802.22), this will likely be counter-productive as the ostensible reason has already been (or is being) addressed via a less contentious route.

This is the latest example where I like Google and in general agree with their direction, but fear that they’re hurting the white space cause by 1) being way too combative, 2) not having a solid technical grasp of what they’re proposing, 3) showing really bad timing (last week’s news on wireless mic detection was not countered, so I’m assuming it was relatively accurate).

Since they’re making their positions so very public and stridently before all of the technical issues are worked out (and I think they will be, primarily via geolocation and transmitter registries ala 802.11y), I fear cognitive radio and white spaces will be tarnished thus making later deployment of cognitive radio into other bands and the deployment of new applications more difficult.

08.11.08

Quick Links 08/11/08

Posted in conferences, quick links, research initiatives, white space at 10:36 am by JamesNeel

First, contrasting viewpoints on white space testing:

(link) From Shure (after the Redskins / BIlls test):

“The FCC’s tests of prototype white space devices at FedEx field prior to Saturday’s game between the Redskins and the Bills conclusively show that spectrum sensing white space devices will cause harmful interference to wireless microphones during live events. Simply stated, the prototype devices were unable to consistently identify operating wireless microphones or distinguish occupied from unoccupied TV channels. More troubling, the devices failed to detect the presence of wireless microphones when switched on – an occurrence that takes place multiple times during any NFL game.

(link) From Motorola:

In an interview yesterday with FierceWireless, Steve Sharkey, Motorola’s senior director, regulatory and spectrum policy, said that the FCC has just finished most of the outdoor white space device testing and that Motorola’s white space device did very well in the tests. Sharkey said that Motorola uses geolocation technology, which means it uses a combination of location technology (such as GPS) and a database that advises the device on what channel to use and whether or not there is compatibility with other white space devices.”The geolocation approach has proved highly reliable,” Sharkey says.

(link) And Verizon wants white space devices licensed:

“Generally we have favored licensed spectrum,” Tauke said at a press conference, “but we are continuing to look at what the potential may be here.” On the other hand, he said he wanted to be certain that these applications, currently being evaluated by the FCC, don’t interfere with Verizon wireless products or anything else. “Nobody has passed the test” just yet, Tauke said.

My two cents. Applying these sorts of political slants to what should be a purely technical assessment (I have no first hand knowledge of the testing and no particular dog in the fight, but it seems to me they can’t all be right on the assessment) is inherent to decisions related to public goods and is a reason (among many) why I wish we would start transitioning to a regulatory regime that more closely mimicked private property.

(link) Effectively the same Motorola story as above, but this link has a line I want to discuss further.

Sharkey calls the tech “absolute, solid protection,” which should make members of the white space coalition happy — though we haven’t heard positive word from Philips, Adaptrum and InfoComm yet, who were also testing devices alongside Motorola, but aren’t using the geolocation technology. That, and the FCC has the final word on all of this, so we’ll just have to wait for that word from on high before we start riotous, interference free partying in the streets

The emphasis was in the original. There was a paper submitted to DySPAN that I wanted accepted (though not a very good paper and not anyone’s I know so ’twas rejected) which unwittingly made what I think is an important point – if 1) a primary user is turning off and on at unpredefined times and 2) is not helping secondary users (via a beacon or via any other method), then 3) secondary users will have to detect the presence of the primary when it starts transmitting. This then means that you simply can’t have assurances of interference-free operation if you want the secondary system to have any sort of useful throughput.

In practice, this means if we are constrained to detecting wireless mics via detection methods only, we will not be able to guarantee interference-free operation.

On a related note, I think IEEE USA did a real disservice to cognitive radio with their advocacy as it sets up the technology to fail by suggesting an impractical condition is inherent to the concept of cognitive radio.

By definition, CRs should be inherently non-interfering on a completely independent basis.

(link) Keith has done a valuable service and posted site measurements as matlab files on the DySPAN conference site for any researcher to use (mmm… real data). Unfortunately the DySPAN site appears to be down at the moment, so do check back later on this link. *Update* Here’s a direct link (zip).

07.25.08

Quick Links

Posted in conferences, quick links, white space at 4:48 pm by JamesNeel

(link) The International Symposium on Wireless and Pervasive Computing has issued a call for papers. Related topics include cognitive radio and cooperative communications. It’ll be held from Feb 11-13, 2009 in Melbourne, Australia. Papers are due October 12.

(link) The schedule for the next SDRF meeting / workshop is now posted. The focus of the workshop is “Government and Industry R&D Agendas for Next Generation Radio Technologies” (read as cognitive radio) and Bill Lehr (MIT) will give a talk on “Building the Ecosystem for Commercial Cognitive Radio”. Interestingly, the agenda page (pdf) lists meeting times for a white space task group. (Other than an agreement that it would be a good idea, it hasn’t actually gotten off the ground yet.)

(link) White Space Tests at the DNC and RNC conventions?

(link) The WaPo has a nice article (from yesterday) overviewing the current round of testing. Interestingly, only the Motorola device is aided by geolocation – something I expect to eventually be a requirement. (The WaPo sometimes requires a login, if you’re asked for one, try these.)

07.18.08

Quick Links – July 18, 2008

Posted in military, quick links, regulation, research initiatives, TV Bands, white space at 3:41 pm by JamesNeel

Or all white space, all the time! But first, some non-white space links… 

(link) Call for more dynamic spectrum policies. Not a lot new there for those active in the policy arena. Key graphs:

“Traditionally, spectrum policy has been all about exclusive licensing for specific service, during extended time periods. The considered opinion now is that static long-term licensing of spectrum hinders fast innovation cycles, and across the board. The fact of the matter is that new technologies tend to diffuse faster than regulations, especially in dynamic sectors like telecom. Already, the considerable strides made in digital technology, such as spread spectrum, software defined radio and mesh networks, do call into question the policy of administrative allocation of exclusive-use licenses.

With novel software, coordination amongst service providers in real time can allow umpteen secondary devices to transmit even while providing the right quality of service and non-interference for cellular customers. The bottom line is that we need proactive spectrum policy to fastforward growth of the most desired applications, as they evolve and take off.”

(link) The US Air Force is funding Finnish cognitive radio research. (I don’t know which Finns. I assume CWC @ Oulu, but I don’t see confirmation on their research page)

Officials from the Air Force, Army and Navy are now funding a Finnish research program that explores new approaches for improving telecommunications network management. 

The ultimate goal is to build on this basic research and create a cognitive network that will use rational decision-making methods to improve the speed and quality of information delivered via Defense Department networks.

(link) Ars Technica has a nice overview on the current round of white space testing.

(link – pdf) The current white space test schedule. Note a sports and entertainment venues are on the schedule.

(link) There was a complaint filed with the FCC on interference from unlicensed wireless microphones. Mmmm politics. I thought I went into engineering to avoid that. (FYI, the Public Interest Spectrum Coalition is not completely new as the article implies; they also were active in the 700 MHz block – see link1 & link 2)

A group calling itself the Public Interest Spectrum Coalition (PISC) and the Media Access Project have filed a complaint with the FCC regarding the unlicensed use of wireless microphones. The Media Access Project has filed a proposed “pathway to authorisation” for existing users that would help to protect new public safety and commercial wireless services operating on UHF channels 52-60 from 17 February 2009.

Michael Marcus has much more on this.

07.10.08

White space news / quick links (July 10, 2008)

Posted in quick links, white space at 11:04 am by JamesNeel

Since, procrastinating on starting my paper reviews = blogging, here’s some random white space links / news:

KU issued a press release on their white space testbed here. I didn’t see anything technically useful in the press release which just says the testbed shows that white space devices will not interfere with DTV reception, but there’s no details on the setup. Poking around the KU website, I did find this white paper (pdf) from May 2007, which has some measurement data from that testbed to backup a claim that adjacent channels could be used. But that seems a bit dated.

(link) Sports stadiums have offered their facilities for live testing of white space devices this fall.

(no link – first-hand reporting!) It looks like the SDR Forum (SDRF) will be spinning up a project to develop an analytic model for mobile white space devices. There’s supposed to be an initial phone call in late July to organize the project and based on other discussions, I believe this activity will be run out of the SDRF cognitive radio working group (CRWG) beginning in August.

If it is indeed hosted out of the CRWG, we’re pretty liberal about accepting contributions from non-SDRF members, so even if you’re not in the SDRF, you can participate (though bylaws say you can’t vote nor could you hold a leadership position). 

I’ll post more information about this after the late July phone call.

06.26.08

Quick Links 6/26/08

Posted in companies, conferences, quick links, white space at 9:37 am by JamesNeel

(link) DySPAN demo synopses have been posted.

(link) Omesh is a new (to me) cognitive network spinout from the University of Toronto.

(link) FCC to being field testing of white space devices soon. [Most of the article is about MSTV + Shure vs the WSC]

(link) A press release on the policy / DSA Yuma field trials by Shared Spectrum, Thales, and Harris.

06.19.08

White Space Workshop Panel Session

Posted in conferences, spectrum, white space at 7:45 pm by JamesNeel

Notes below the fold.

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Peter Tenhula (Shared Spectrum)

Posted in conferences, white space at 7:00 pm by JamesNeel

Notes below the fold.

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Ser Wah OH, I2R (Singapore)

Posted in research initiatives, white space at 5:45 pm by JamesNeel

Didn’t really follow it too closely. Key result seemed to be -118 dBm for 90% Pd and -123 dBM for wireless microphone.

Notes from Lary Alder (Google) at White Space Workshop @ SDRF

Posted in TV Bands, white space at 5:15 pm by JamesNeel

Notes below the fold

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Notes from (Paul Greenis) Adapt4 at White Space Workshop @ SDRF

Posted in cognitive pilot channel, devices, TV Bands, white space at 2:47 pm by JamesNeel

Notes below fold

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Notes from TDK RF Solutions (instead of Carl Stevenson from 802.22)

Posted in TV Bands, white space at 1:31 pm by JamesNeel

Didn’t find very much interesting in this talk. Kinda high level view of what cognitive radio is and the associated regulations (there was a nice summary slide of all the FCC activities with SDR, CR, and white space devices). 

Basic point is CR will be important, but it’s not easy, and regulations will be changing over time.

Question: John (Vanu) asks how you do interference measurements for new devices using radically different devices. TDK suggests you work with all parties and find ways to make them happy with the testing

Notes from Bruce (MSTV) at White Space Workshop @ SDRF

Posted in cognitive pilot channel, TV Bands, Uncategorized, white space at 1:24 pm by JamesNeel

Unfortunately wordpress ate my post and this was where I was taking my notes, so highlights from memory (take the numbers with a grain of salt). It’s really a shame as it was quite a detail-rich presentation. I might supplement this later after I get a copy of the slides.

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Notes from the White Space Workshop @ SDR Forum in Portland

Posted in TV Bands, white space at 12:10 pm by JamesNeel

Probably going to be a long post, so it’s below the fold. Typed in real time, so forgive the fact that there’ll be more typos than usual.

Kicked off by John Chapin (Vanu, Chair SDRF) – noted rapid projected growth in spectrum demand (an extra 500 MHz required under 5 GHz perhaps in the next 15 years). I’ll try to gather my notes from each talk in a different post.

06.17.08

Google suggests wireless mics should switch to CDMA

Posted in shameless self-promotion, TV Bands, white space at 9:23 am by JamesNeel

Google has a combative white paper up arguing that wireless mics should switch to CDMA (with cognition to adapt spreading codes). Here’s a direct link to paper (pdf)

My comments:

1) I don’t think implicitly arguing that wireless mics should switch to spread spectrum will advance the white space cause. Comes across as a bait (no interference to legacy systems!) and switch (legacy systems must change!).

2) I think you can get very close to what Google wants with pseudo-noise codes or fast frequency hoppers as opposed to adaptive codes which could have some significant stability issues with 300+ uncoordinated adapting mics all in close vicinity unless done right.

3) I do think it would be a good thing to use digital spread spectrum mics instead of analog mics, but Google (and this applies to me as well) is the wrong one to be making the case. Because of the messenger, it’ll likely slow the transition.

06.12.08

OFCOM WhiteSpace Plans

Posted in white space at 1:49 pm by JamesNeel

OFCOM announced plans to release white space from TV rebanding in Britain. The key graph:

The first white space will be released early next year in Carlisle, Cardiff and Manchester. Later phases will offer combined spectrum, allowing national services, with the final awards being made in 2011.
Users would be able to decide themselves which technology they use and the licences would be tradeable.

The official OFCOM announcement is here.

06.05.08

Quick Links 6/5/8

Posted in conferences, spectrum, white space at 9:55 am by JamesNeel

Wireless Net DesignLine article on the increasing use of interference avoidance techniques in the 2.4 GHz band.

At the same time as VT’s symposium, Microsoft’s Research Symposium on Cognitive Radio is going on over the 5th and 6th. Papers and presentations are supposed to be published online soon.

An overview of Pentagon efforts to address spectrum issues in Signal Magazine online.

The wireless mic community still doesn’t like unlicensed white space devices (link).

05.22.08

White Space Quick Links (May 22, 2008)

Posted in white space at 10:06 am by JamesNeel

Voyant got a contract to build white space radios. 3000 doesn’t sound like a real big order. But $2 million doesn’t sound like a lot of funds for development either.

Larry Page is in DC today to talk about google’s white space proposal with Michale Calabrese. (via) I think the whole talk will be available at that link. Listening, I’m hearing lots of good things (support for dynamic spectrum markets) and lots of objectionable things (e.g., an all frequency, all-mode SDR will be $5).

(Quasi live-blogging – ignoring the stuff not directly related to cognitive radio / wireless)

Larry asserted that you could turn off a transmission in a single ms. However, packet/frame lengths and processing times for the high data rate systems they want to use simply won’t support that.

Lengthy comment in support of completely turning off TV broadcasts and switching everyone to cable/satellite, but noting political difficulties (particularly must-carry requirements). I think that was about right.

Discussion of drop in relative ranking of the US broadband access. After noting that some places in the US have very high broadband penetration (like DC), Larry went on to lament the lower access levels in the US. My thoughts are it’s primarily a function of the lower relative urbanization of the US which makes deploying broadband far more expensive + the US deploying broadband earlier (and now stuck with a bit of legacy equipment).

Larry defends the business model of municipal WiFi?

Update

I decided I was being a bit too negative in tone on a couple things in the post.  I think this was because of my recent disposition to the two subjects in the blog post. I need to read it again, but I think I have a significant theoretical issue with the Google white space white paper, and the Voyant news came via a stock advertisement which looks the world to be flogging a dying stock.

So tempering a couple of my negative comments:

1) First, while various standards have long frame lengths and just because it normally takes a while to sense a signal, it doesn’t mean that a different standard couldn’t be defined that permit that level of responsiveness. However, I still expect this will severely cut into the achievable data rates (you lose transmission times istening, plus lose efficiency by using shorter frames) 

2) A $2 million dollar order would be a great order for a startup. However, Voyant is not a startup. Nonetheless, this is the first white space device order I’ve seen, so that’s good news for the cognitive radio community. However, it seems just a bit premature as it’s far from certain at this time that the regulatory environment will permit their use.

05.17.08

White Space News Roundup (May 17, 2008)

Posted in TV Bands, white space at 9:43 am by JamesNeel

On the Google public policy blog, there’s a link to a Google white paper (pdf) describing their geolocation proposal in more detail (though not a lot more). As opposed to earlier reports, they appear to be deemphasizing the aspect of having existing mics upgraded to include a beacon and are going more for a pure geolocation / database method (I think that’s preferable).

They’re also engaging in a little bit of the “cure for everything” mentality that is an unfortunate trait of the cognitive radio community. Specifically, Google is also touting the ability of unlicensed mesh White Space devices to aid the public safety community after a natural disaster. While the combination of mesh networks and cognitive radio is frequently touted for those purposes, I think it’s an unneccessary distraction in this case.

Specifically, what the unlicensed White Space community needs to focus on is just demonstrating non-interference with incumbents – which unfortunately hasn’t gone as smoothly as it could have. As additional features creep into these prototypes, the chances for bugs will neccessarily go up and any error at this point is being seized upon by the incumbents as proof of the infeasibility of DSA & cognitive radio.

Other notes:

In the last post on Google’s white space proposal, I mentioned that theaters and churches were also objecting, but I did not have links to support that assertion. Finally, here’s some news articles to support those claims.

Grand Ole Opry (along with CMT and MTV) complains about White Space.

A church audio blog following the controversy. It’s a short link roundup, but the Shure link is interesting to follow (they’re against it). While I’m on the topic of Shure, Michael Marcus rightfully rips into them in this post where he points out that frequencies suggested for use by Shure for wireless microphones, often unlicensed, interfere with licensed public safety incumbents! (Someone once said something about motes, beams, and eyes that seems apropos.)

05.14.08

Short Links

Posted in overview, Vertical Handoff Management, white space at 9:42 am by JamesNeel

Management of Vertical Handoffs

A news release noting an installation of a cognitive system from In Motion Technology for East Texas Medical Center (ETMC) Regional Healthcare System Emergency Medical Services. Reading into their solution page and technology page, what they’re actually doing is optimizing the choice of network assignment based on link information and performing vertical handoffs. Think normal mobile assisted handoffs (maintain a ranked list of link state information from multiple base stations and switch when some hysteresis threshold is crossed), but not restricted to a single wireless interface.

It’s not what most people would call full-blown cognitive radio, but this is representative of how I think cognitive radio is going to roll out – function by function.

White Space Device Resubmission

Motorola is resubmitting their white space device to the FCC for testing. Not much information in there but it’s interesting to note.

US Navy Video on spectrum

Via Elastic Spectrum, comes this video entitled, “Electromagnetic Spectrum, Critical to our Nation’s Security and Economy.” Beyond the video (kind of an overview), there’s also several nice reference documents linked on the sidebar at the site

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