Steven J. Crowley, P.E.
It appears Google is finalizing the design of what it variously calls, in recent FCC filings, a “personal communication device” or an “entertainment device.” It further appears it would be an unlicensed device supporting both Wi-Fi and Bluetooth, and operate at low power in the bands 2400-2483 MHz and 5180-5825 MHz.
In two applications requesting special temporary authority (STA) under the FCC’s experimental radio service, Google says it expects to have fully compliant hardware ready for submission under FCC’s equipment authorization testing process by August 2012. If all goes well, authorization could come a few weeks later, in late August or September. Then, Google would be free to manufacture, market, and sell the device.
Since the design has to be locked down before the equipment authorization process proceeds, with only minor changes permitted thereafter (without repeating the whole authorization process), submission of equipment to the equipment authorization process in August means its development will then be essentially finished for that hardware release.
In the experimental applications, Google doesn’t say much about use cases for the device, but does discuss the goals of the tests:
Testing of the prototype device is intended to reveal real world engineering issues and reliability of networks. The device utilizes a standard Wi-Fi module, and the testing is not directed at evaluating the radio frequency characteristics of the module (which are known), but rather at the throughput and stability of available Wi-Fi networks that will support the device, as well as the functionality of the device. Experimentation to date has included, and will continue to include, functional testing of all subsystems, including Wi-Fi and Bluetooth radio. Users will continue to connect their device to their home Wi-Fi networks and to publicly available Wi-Fi networks.
Trying to infer what’s going on becomes more confusing because Google appears to be operating under two separate authorizations for special temporary authority for the same device. Usually, one authorization suffices, which is made sufficiently broad to cover any anticipated tests.
Usually we don’t pay much attention to experimental call signs. We do here because we’re dealing with two authorizations, to help keep them straight.
The applications were originally filed in December 2011 and approved. Renewal applications for both were filed in May 2012 and approved within a few days, and are good for six months from approval. One authorization, assigned call sign WF9XLG, specifies two bands of operation, 2400-2483 MHz and 5180-5825 MHz. The other, WF9XKU, specifies just one band, 2400-2483 MHz.
Another distinguishing feature is the emission designators, a shorthand for classifying radio emissions. WF9XLG specifies G1D, which could cover the 802.11b variant of Wi-Fi. WF9XKU specifies W7D, which could cover an OFDM variant of Wi-Fi such as 802.11g, and F1D, which could cover Bluetooth. There is not a strict one-to-one mapping of radio technologies and emission designators.
Even though there are two separate authorizations, I can’t imagine there being two separate products covered by the above. (Why put out an 802.11b-only device?) So, why did Google file two applications? I don’t know. I suspect that the first application, WF9XKU, was filed intending to cover everything. Later someone noticed it didn’t cover certain prototype functionalities, so the application for WF9XLG was filed a couple weeks later. It was probably easier to just file a second application than go to the trouble of trying to amend the first one.
In the May renewal applications, Google takes the opportunity to expand the scale of its tests. The original test description in December 2011 was to test 102 devices under WF9XKU and 252 devices under WF9XLG. Under both call signs, testing would be within 121 kilometers of four cities: Los Angeles, New York City, Mountain View, California, and Cambridge, Massachusetts. Under the renewal for each call sign, Google asked that up to 700 units be permitted within 322 kilometers of Mountain View:
The expanded Mountain View test area is intended to allow testers to connect to new networks in different regions to test for Bluetooth and Wi-Fi interoperability, functionality, and compatibility with various types of hardware and networks, which can vary on a regional basis, as well as to facilitate different modes of use (use of applications and services likely will vary during business or other travel as compared to standard home or office use) and a variety of environmental and use factors that will, or have the potential to, affect performance, including altitude (which affects cooling rates, for example), humidity, air quality, and frequency of use. The expanded number of devices also will allow Google to examine the increased load effects of streaming content and particular use applications on functionality and latency.
Google provides some information on the location capabilities of the device:
All devices will continue to be registered to Google employees, and to be used solely by Google employees (except that Google requests authority to permit up to five devices at any given time to be used by third parties under the supervision of Google employees). Google will continue to maintain a record of each device so that devices may be recalled at any time during testing and upon completion of testing. Device location can be tracked using Wi-Fi geolocation (typically accurate to about 75 meters), and Google has the ability to remotely disable any or all test devices should it become necessary. Moreover, GPS tracking of the devices remains in testing and development, and is expected to become functional during the STA period.
Steve is a consulting wireless engineer who provides support for projects involving technology analysis, standardization, regulation, patent portfolio management, and corporate communication. Clients include vendors, service providers, asset managers, government agencies, and other professional service providers.
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Steven J. Crowley, P.E.
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