Steven J. Crowley, P.E.
In a November 20 FCC filing, the Wi-Fi Alliance reported on recent meetings with FCC staff on the subject of Wi-Fi/LTE-U coexistence. The Alliance says consensus was reached on the following points at its November 4 Coexistence Test Workshop:
- The LTE-U specification can be further refined to provide greater clarity, and recent updates to the specification are a good step forward
- A broader set of test scenarios than currently exists is likely necessary to test LTE-U’s fairness to Wi-Fi
- Stakeholders are committed to collaborating within Wi-Fi Alliance to develop an industry agreed test regimen for LTE-U devices
A follow-up workshop is scheduled for the week of February 8.
In LTE-U, different companies can come away with different views of the same event. We’ll see if these consensus points hold.
The Global mobile Suppliers Association (GSA), representing mobile industry vendors, has commissioned a report on opportunities in LTE broadcasting. Prepared by a UK business consultancy, it’s part marketing document making a case for impressive growth in the LTE Broadcast business, which it turn makes it a useful sales tool for GSA members.
Interference arguments at the FCC would become more objective and less dependent on wordplay under a proposal by the FCC’s Technological Advisory Council (TAC).
Risk-informed interference assessment is a quantitative methodology intended to draw out the trade-offs between risks and benefits of new services. By using it interference assessments would move from, in the words of a TAC report, “What’s the worst that can happen?” to “What can happen, how likely is it, and what are the consequences?”
IEEE 802 and 3GPP are working together more on coexistence of Licensed Authorized Access (LAA) and Wi-Fi. Since November, each group has made a presentation to the other. There’s been an exchange of liaison statements, the latest on March 18 when IEEE 802 sent 3GPP two statements containing several requests and recommendations.
On October 13 Google filed two experimental radio applications with the FCC. The first seeks permission to test in the 3.5 GHz band in Mountain View, California and in suburban Washington D.C. The second is for testing in the 5.8, 24, 72, and 82 GHz bands in Mountain View and San Mateo County, California. The applications are redacted. Most technical detail is unavailable, but here’s what’s visible.
Google has applied to the FCC to conduct “airborne” testing of data over millimeter-wave frequencies in Northern Nevada. I saw the frequencies and thought this was another test of millimeter-wave radar for automatic cruise control; Google has applied to test that several times since 2011. The emission designators for the current transmissions, however, contain the symbols D1D; that’s data, not radar. An application to the FCC to test millimeter-wave data is a first for Google.
Google has filed an application with the FCC to conduct drone tests in New Mexico. The company has sought confidential treatment of its application form and exhibits. All we have to go by now is one exhibit that’s been redacted for public consumption. Google provides some detail, and we can try to infer some more.
The interaction of radio waves in free space has never been much of a concern to this wireless engineer. Propagation models do a pretty good job of estimating received signal strength. Receivers are designed to select desired signals and reject undesired ones, within limits. “Interference takes place in the receiver,” I’ve heard more than once. Yes, there are a lot of signals in the air at once, but I’m more interested in the end result.
Once a year the Telecommunications Industry Association (TIA) holds a membership meeting that looks forward to tomorrow’s networks. Last week I moderated a spectrum panel at the “Network of the Future” conference in Dallas, and stayed for the rest of the wireless track (parallel tracks I didn’t attend related to software-defined networking and big data).
Sinclair Broadcast Group, the country’s largest TV group owner, is also a communications technology proponent. With partner Coherent Logix, a developer of software defined radio (SDR) technology, it’s behind one of several systems up for consideration in the Advanced Television Systems Committee (ATSC) for next-generation television in the U.S.. The new standard will be known as ATSC 3.0.
Update March 27, 2014: A few days after this application was filed, it was apparently withdrawn. The links below to the application form and exhibits no longer work, and I see no trace of the application. The essential application information is still in my original post below. I don’t know why the application was withdrawn. The application was apparently prepared by an engineer based at a Google office in Seattle. To me, it seemed incomplete in some aspects. Usually, such applications are prepared by Google’s attorneys; I speculate this caught the attorneys unaware, they didn’t like it, and they pulled the application for their review. Look for it to be recast and filed again.
Google yesterday filed an application with the FCC for an experimental radio license that apparently involves connected-car technology. No specific location for the experiment is indicated; it’s to take place in the “Seattle and San Francisco areas.” A total of 10,000 transmitting units are involved, with 5,000 being custom experimental devices manufactured by Google, and 5,000 consisting of off-the-shelf CSR CSR8311 Bluetooth ICs, which the manufacturer describes as the “first Wideband Speech IC qualified for the automotive market” and “the first Bluetooth low energy IC ready for automotive use.” I speculate the IC will be used in combination with the Google device, for a total of 5,000 experimental radio systems. There’s only one frequency band (2402-2480 MHz) and one emission designator (1M00F1D) specified in the application; these parameters are consistent with Bluetooth, so the custom Google transmitter would seem to have Bluetooth-like emissions.
Supporting exhibits are usually filed with experimental applications. Google has done so, but designated them “not available,” presumably invoking confidentiality provisions of the FCC’s Rules. It’s standard FCC practice to have the applicant make the confidentiality request visible to the public. Google has not. Furthermore, from the exhibit descriptions, it appears Google has not even filed a confidentiality request. I expect the FCC to ask Google to do so and to make it public. If there are updates to this application, I’ll update this post.
On January 22 Google filed an experimental radio application at the FCC. The company has requested confidential treatment of the application, so significant portions aren’t publicly available.
As part of the filing, Google filed a request for confidentiality, which is public. It contains a few technical details. Two separate transmitter types are identified, both operating at low power in the range 76-77 GHz, and using FM and BPSK modulation. The 76-77 GHz band is used for short-range vehicular radar and, knowing Google’s interest in vehicles, it’s reasonable to assume that is what the experiment involves.
A study commissioned by UK telecom regulator Ofcom examines tradeoffs among many mobile indoor-coverage technologies, and suggests the agency help consumers learn more about them.