Unlicensed spectrum has never been more popular! The reason people love unlicensed spectrum is because it is the “public commons” of spectrum that is open to anyone to use and has led to innovations that people use every day. Technologies such as Bluetooth, cordless phones, baby monitors, and Wi-Fi all come from use of unlicensed spectrum, and we expect to see many new innovations in the near future as a result of unlicensed spectrum, such as self-driving cars.
Wireless broadband carriers are now bringing forward a new protocol to route traffic that will make use of unlicensed spectrum to take some of the burden off of the licensed spectrum they use to transmit your phone calls, videos, and other Internet traffic. The new protocol is called LTE-U (adding the “U” to the 4G service called “LTE” because it adds unlicensed spectrum to the bands wireless carriers can use to serve their paid subscribers).
LTE-U is all over the news right now because there is only so much quality spectrum available and how that spectrum is used has huge impact on both companies and consumers. New uses of spectrum must be approved by the Federal Communications Commission (FCC) in order to prevent interference and ensure the public’s spectrum is used efficiently and in the public interest. If wireless carriers get LTE-U approved, it will free up more space for traffic on wireless networks, which in the end saves money for the carriers based on their network management and deployment decisions.
However, other industry advocates, like the National Cable and Telecommunications Association (NCTA) and Google, have noted that the protocols that LTE-U uses can slow down or degrade other uses of unlicensed spectrum, including Wi-Fi connectivity. How could this happen? Wi-Fi and other unlicensed devices have always functioned in ways that prevent this sort of degradation, using coexistence mechanisms such as the feature called “Listen Before Talk” (LBT). Such mechanisms prevent traffic from shifting to a specific frequency until the device can sense that the frequency is clear, a decentralized way of controlling traffic on unlicensed spectrum.
One simple way to picture this is if the unlicensed band was a dinner table conversation where people naturally follow LBT rules, or else you end up talking over each other and the conversation doesn’t work. In this example, some LTE-U protocols allow people to talk over each other at the dinner table, degrading the quality of the quieter talker, and their ability to effectively communicate.
Unfortunately, early versions of LTE-U previewed in the United States don’t use LBT protocols. Instead these versions of LTE-U use the unlicensed spectrum bands without checking for other users first, which has the effect of slowing or degrading other unlicensed traffic. Like a rude talker at the dinner table, these early versions of LTE-U simply talk loud enough on the unlicensed band to make it hard for some to talk. This is in violation of basic Wi-Fi standards. Since LTE-U is centrally controlled by the licensed wireless carrier, they could even potentially set LTE-U protocols to degrade unlicensed spectrum bands just enough to edge out services that compete with their offerings, such as digital media, video, and music.
What happens when the average consumer doesn’t think they can rely on Wi-Fi connectivity? Those consumers may end up switching to paid licensed carriers. Our FCC filing noted that 90% of iPads and other tablets use exclusively Wi-Fi connectivity. Imagine the windfall that would come if licensed wireless carriers were able to nudge those consumers to purchase a wireless plan instead of relying on Wi-Fi.
Some commenters claim erroneously that FCC intervention into the LTE-U rollout would pick winners and losers in a business dispute. Those commenters fail to acknowledge that the current protocols for unlicensed spectrum are there not to protect other businesses, but instead protect the public interest that is derived from unlicensed spectrum. No one owns unlicensed spectrum, and the rules for its use are purposeful and neutral to business interests. All innovations that have developed on this commons did so under basic rules of the road, and LTE-U should not get special treatment.
Many news reports have asserted that this dispute over LTE-U is a fight between wireless carriers and big cable companies. Public Knowledge doesn’t often agree with the big cable lobby like NCTA, but in this instance, their FCC filings show a great loss for consumers if LTE-U is allowed to roll out without simple “do no harm” practices incorporated into its protocols. That’s why Public Knowledge and other consumer groups have raised those concerns at the FCC. We often note that when big companies debate, it is the consumer’s perspective that gets lost and sometimes ignored. The FCC’s obligations to the public interest means they must take into account the impact on consumer uses and benefits of Wi-Fi and unlicensed spectrum before allowing approval of LTE-U.
The FCC can prevent harm to consumers and protect their widespread use of W-Fi and other unlicensed spectrum. In the past, standards based groups like the 3GPP and IEEE have collaborated to ensure that licensed and unlicensed protocols worked in harmony, but unfortunately, LTE-U proponents like Qualcomm have pushed those two groups away from working together. That leaves the FCC to arbitrate these concerns. Our coalition of public interest consumer groups makes recommendations to the FCC with the goal of meeting this need for coordination. As the licensing agency, the FCC sets simple limits on licensed spectrum and there is no reason that these shouldn’t apply to services that link licensed and unlicensed in a way that prevents the greater public interest benefits of unlicensed spectrum.