Earlier this week, we responded to the FCC Notice of Inquiry on expanding flexible use, mid-band spectrum between 3.7 and 24 GHz, which explicitly called out two specific band ranges — the 3.7 to 4.2 GHz band, which we believe is suitable for licensed operation, and the 5.925 to 7.125 GHz band, which we believe is suitable for unlicensed operation. This is an important FCC initiative that aims to open more spectrum for wireless communications in the U.S. and will be essential to maintaining and achieving American leadership in 5G by complementing mobile millimeter wave deployments in the 28 GHz and 39 GHz range, and sub-6 GHz deployments in the 600 MHz, 2.5 GHz, and 3.5 GHz ranges.
We have already seen great progress from the FCC. Last year, the FCC opened 11 GHz of spectrum in multiple millimeter wave bands with its Spectrum Frontiers Ruling, followed by the successful auction of 600 MHz spectrum in April of this year, which T-Mobile will initially use for LTE deployments and eventually for 5G NR. For the mid-band, the FCC has also allocated spectrum in the 3.5 GHz range for the Citizens Broadband Radio Service (CBRS), which opens a total of 150 MHz of spectrum for mobile use cases and introduces a new 3-tiered sharing framework that allows incumbents to efficiently share spectrum with other users — already targeting initial LTE deployments for next year. In addition, one U.S. operator, Sprint, is working with us to deploy 5G NR in its existing 2.5 GHz spectrum (Band 41) in late 2019.
The use of mid-band spectrum, especially bands below 5 GHz will play an integral role for 5G enhanced mobile broadband deployments starting globally in 2019 — which will be key to delivering wide-area capacity and achieving multi-gigabit speeds that consumers around the globe demand. And that is why it is so important for the FCC to allocate more mid-band spectrum for the U.S. to enable more bandwidth for 5G services.
So, how exactly should the FCC proceed with the identified mid-band spectrum in the U.S.?
First, we proposed that the 3.7 to 4.2 GHz band be allocated as licensed spectrum for 5G. This band offers promising attributes for mobile broadband — possessing very good propagation characteristics to support wide-coverage with fewer base stations than high-band spectrum requires, while offering 500 MHz of bandwidth to support much wider channels (e.g., 100 MHz per operator license) and much higher throughput than low-band spectrum typically offers. Access to wider channels, such as 100 MHz, is important for these new bands to fully leverage 5G NR’s inherent ability to use these channels to and deliver improved performance and user experience. As this proposed band is adjacent to the 3.5 GHz CBRS band (3550 to 3700 MHz), allocating this band for licensed cellular service will provide opportunities for devices to share or reuse RFFE (RF Front End) components (e.g., LNA & PA), which will keep device complexity low. In addition, the 3.7 to 4.2 GHz band offers potential for spectrum harmonization with other counties targeting this band range for 5G, such as Japan, Brazil, and the EU (e.g., Italy, France, and the U.K.).
Second, we recommended that the 5.925 to 7.125 GHz band be allocated as unlicensed spectrum, further extending the existing 5 GHz unlicensed bands, which unleashed unprecedented unlicensed device innovation and development of Gigabit LTE with Licensed Assisted Access (LAA), Wi-Fi and its evolution to 802.11ax, as well as upcoming technologies like MulteFire. Opening 1.2 GHz of unlicensed bandwidth will fuel the need for even faster broadband access by increasing the availability of wider channels — and bring new use cases such as private networks for the industrial IoT — also key to next-generation wireless technologies including 5G NR based spectrum sharing that is currently under 3GPP development. This band is also adjacent to the existing 5 GHz unlicensed bands, by making the FCC rules for this new band technically compatible with the existing 5 GHz bands, the wireless components supporting unlicensed broadband operations at 5 GHz can readily be shared or reused. And to make better use of this significant amount of unlicensed spectrum, we are working with our wireless industry partners, standards organizations, and other stakeholders on exciting new ways to share spectrum far more efficiently, such as synchronized unlicensed sharing. Our filing contains some our ideas in this regard, and we’ll be discussing more on this topic as we head into the 5G NR Spectrum Sharing Study Item, so stay tuned.
Finally, to ensure timely rollout of 5G services, the FCC needs to start facilitating the transition to mobile wireless uses of these bands. As with all new spectrum allocations, the process to move current incumbents (such as satellite receivers) will take some time. In our response to the FCC, we provide recommendations on how new users can gain access to the spectrum before it is completely cleared — by implementing either exclusion zones or possibly using advanced spectrum sharing techniques that will protect the incumbents.
The use of mid-band spectrum is of course only part of the bigger picture for 5G, which also will leverage low-band spectrum in the sub-1 GHz range and high-band millimeter wave spectrum, using licensed, unlicensed, and shared regulatory paradigms. And getting more spectrum for 5G is a global effort; in case you missed it, I recently published a blog post discussing the global 5G spectrum status.
At Qualcomm, we are actively working with regulators, operators, and partners all over the world to ensure a smooth 5G rollout, and we are excitedly anticipating the first global 5G NR network and device launches — including millimeter wave operations in a smartphone form factor — in 2019. Stay tuned for further updates.