Is Wi-Fi in Danger?

Upcoming tests seek to predict whether Wi-Fi can survive cell companies' using its frequency bands.

(Like it says in that disclaimer over to the right, this post reflects the opinions of its author - not his law firm, its other lawyers, or its clients.)

Wi-Fi may be one of the best ideas anybody ever had. When the technology was still expensive, 20 years ago, its main application was connecting servers to computers in the workplace and to cash registers in large retail stores. It still serves those purposes today " and more.

Now, with costs greatly reduced, Wi-Fi is ubiquitous in homes, coffee shops, airports, hotels, car-repair waiting rooms - pretty much anywhere people might use a laptop or a tablet. Here in the CommLawBlog bunker, for example, we have good Wi-Fi service everywhere (except that dead spot behind the climbing wall). A long-range version provides Internet service to people who can't easily connect to cable or DSL phone lines.

Wi-Fi has a populist, democratic appeal. Anyone can easily set up an access point and provide service to family or customers or guests. Now, though, many see Wi-Fi as under threat from less populist, less democratic forces: namely, the wireless phone companies.

The phone companies' cell systems operate in licensed spectrum acquired at auction for prices totaling tens of billions of dollars. There is never enough spectrum. One way cell operators can ease pressure on their spectrum: When a cell phone is in reach of a Wi-Fi signal, its carrier has the option of moving data over Wi-Fi rather than cell towers. One carrier uses this capability as a marketing point.

The carriers' Wi-Fi usage generally blends in with other Wi-Fi applications and, so far as we know, has not caused significant problems. (Irony alert: The handset manufacturers include Wi-Fi so customers can save money on their phone-company data plans, but the phone companies are using their customers' Wi-Fi to save money in moving their data.)

Now the cell phone companies have plans to make greater use of Wi-Fi frequencies in ways that may cause real trouble for Wi-Fi.

First, a little terminology. Some people use "Wi-Fi" as synonymous with any unlicensed data transmission, but here we'll be more precise. Wi-Fi by definition conforms to a family of technical specifications with the catchy name IEEE 802.11. The term "Wi-Fi" is a registered trademark of an outfit called the Wi-Fi Alliance, which licenses the mark to manufacturers whose products comply with the relevant 802.11 standard. The standardization of specifications explains why every Wi-Fi-branded device works perfectly with every other Wi-Fi-branded device. This is also why a Wi-Fi device can function well in the presence of many others, as in a crowded Starbucks: the 802.11 standards tell multiple devices how to spread themselves over the available channels, and how to slow down transmissions when necessary to counter interference.

The phone companies handle data transmission between handsets and cell towers using a different set of standards called LTE - also a trademark, this one held by a European standards body (standing for "Long Term Evolution.") When the phone ads refer to "4G," they mean LTE. The standards are highly flexible, covering a wide range of data speeds over many frequency bands. If you ever took your cell phone overseas, swapped in a local SIM card, and received excellent data service, you benefited from the global standardization of LTE.

The phone companies look at their debt from past purchases of auctioned spectrum, and think about how to finance yet another auction coming up later this year. Then they look at the free, unlicensed spectrum used by Wi-Fi. They reason, as any rational person would, that moving more traffic off the expensive auctioned spectrum and into the free Wi-Fi bands could save money. This works best, though, if they don't use 802.11-type Wi-Fi, but instead use a version of LTE - called LTE-U - which is designed to function on the unlicensed spectrum used for Wi-Fi. The problem? In response to an FCC inquiry on the question, Google says that LTE-U will hog the channel and not let Wi-Fi get through. Qualcomm, which developed LTE-U, says in response that Google is wrong - that LTE-U is "a friendly neighbor" to Wi-Fi. About a hundred other parties have weighed in.

All this puts the FCC in a bind. Its rules for the Wi-Fi bands allow any signal for any purpose, so long as the signal conforms to certain basic technical criteria. The 802.11 standards (and many others) meet this requirement, and presumably LTE-U does as well. Wi-Fi has mostly served small users, rather than big providers, but nothing in the rules requires this. From a legal standpoint, the FCC presently has no authority to exclude LTE-U. But from a practical standpoint, Wi-Fi has become so important to the economy, and such a major convenience in people's lives, that to let LTE-U degrade it would be unthinkable.

The FCC's engineers are now doing what engineers do, when faced with a hard problem: they're trying to get better data. They have given Qualcomm a special temporary authority (STA), a kind of short-term license, to evaluate the coexistence of LTE-U and Wi-Fi at small Verizon sites in Oklahoma City, OK, and Raleigh, NC. (An STA is needed because the LTE-U devices do not have the FCC certification required for unlicensed devices.) The Wi-Fi Alliance will participate in developing the test plan.

People like to think tests like this can settle a dispute, but more often, the tests lead to fresh controversy over whether the test conditions were realistic and what the results mean. We hope that, this time, having the Wi-Fi Alliance involved in the early stages will promote a consensus around the outcomes, whatever they are.

If you have views on how the tests should be conducted, please speak up. There is no fixed deadline, so we suggest making yourself known soon as possible. To contact the Wi-Fi Alliance, use this website. For Qualcomm, use this one. To file a public comment with the FCC, go to this website and enter Proceeding Number 15-105.