Wireless carriers are a major step closer to using unlicensed spectrum to ease network congestion and boost speeds following the FCC’s authorization of the first LTE-Unlicensed (“LTE-U”) devices on February 22, 2017. LTE-U technology allows carriers to deliver mobile traffic over unlicensed spectrum in the 5 GHz band already occupied by Wi-Fi, Bluetooth, and other technologies. The recipients of the equipment authorizations are Ericsson and Nokia. The certifications by the FCC’s Office of Engineering and Technology (“OET”) mean that the devices in question satisfy the technical criteria of the FCC designed to prevent harmful interference to radio communications services. Those rules stipulate that unlicensed devices must accept any harmful interference they receive from any source. Unlicensed devices have been certified for decades. The announcement of the certifications of the LTE-U devices represents an important milestone in the FCC’s recent focus on spectrum sharing and broadband deployment because these devices are specifically designed to support broadband and work in an integrated fashion with commercial mobile broadband providers’ networks. In short, this is not just a pumped up version of Wi-Fi offload, which carriers have used for years to relieve congestion on mobile networks. These devices mean that the hundreds of megahertz of 5 GHz spectrum that the cable and unlicensed communities fought for years to gain access to – the so-called Unlicensed National Information Infrastructure (“U-NII”) bands – will now be available for LTE technologies.
Wireless carriers generally hold exclusive licenses to operate in certain spectrum, while Wi-Fi, Bluetooth, and many other devices operate without radio licenses provided they can show adherence to certain emissions and other technical requirements designed to protect licensed services. The LTE-U authorization follows years of wireless industry pressure to open up unlicensed frequencies to offload mobile traffic and ease network congestion. The ability to offload traffic to Wi-Fi has become increasingly important as the demand for streaming video continues to grow. LTE-U only works over short distances, but its supporters highlighted its potential to improve over Wi-Fi capabilities using the U-NII spectrum to deliver gigabits of data at LTE speeds while improving capacity in buildings and city centers. However, LTE-U faced opposition from cable and internet service providers concerned that increased traffic would degrade the performance of Wi-Fi, Bluetooth, and other technologies operating in the same spectrum. Opponents noted that Wi-Fi networks already carry the bulk of mobile device traffic and asked the FCC for more time to evaluate LTE-U technology.
The Wi-Fi Alliance developed co-existence guidelines for Wi-Fi and LTE-U and released an evaluation test plan in late 2016. Tests have been conducted under the plan and, while the head of OET stated last week that he understood the LTE-U devices were evaluated successfully under that test plan, he emphasized that the certifications, as is the case with all equipment authorizations, merely demonstrated that the LTE-U devices in question met the FCC’s unlicensed device technical requirements for operation in certain bands. The devices have not been certified to not cause interference to or receive interference from Wi-Fi devices.
Following the authorization, multiple carriers announced their plans to deploy LTE-U devices in the next few months, with other wireless providers expected to follow suit. The LTE-U devices will complement existing LTE service, using compatible base stations located across the country that also serve as base stations to licensed LTE devices.
These certifications and the carriers’ related announcements of their intent to deploy the devices raise two important questions. First, will the deployment of these devices at scale lead to congestion and interference concerns in the U-NII bands? Cable operators, wireless internet service providers, and other Wi-Fi proponents will be watching closely. Second, will access by carriers using LTE-U devices in the hundreds of megahertz in the 5 GHz band reduce pressure for more licensed spectrum for commercial mobile carriers? The amount of U-NII spectrum available to mobile carriers deploying LTE-U devices is approximately the same, if not slightly more, than all of the spectrum licensed to commercial mobile carriers, and increasingly more and more usage is characterized by subscribers that are effectively stationary, in and near buildings and in public spaces and venues. It will be most interesting whether these certifications, in retrospect, end up being transformational in terms of how the spectrum is managed in years to come.