Blog | Doug Smith | June 13, 2019

Spectrum Needs for the 5G Future

5G has taken center stage in the wireless industry—and rightly so. American companies and consumers are poised to benefit from the next wave of technology and innovation. Industry and regulatory stakeholders are also taking steps to advance spectrum and network deployment plans for the 5G future.

President Trump has prioritized 5G as a top policy goal in this Administration’s efforts to expand economic growth and extend America’s leadership in the global economy. The Federal Communications Commission (FCC) is owed tremendous praise for successfully bringing to market new spectrum in the mmWave band through its recent auctions and a planned third auction later this year.

Advancing U.S. leadership in 5G, however, requires an “all of the above” policy for new spectrum availability—a position that’s predicated on the fact that no single spectrum band can solve all the deployment and network challenges in the 5G future. While increasing mmWave spectrum availability is certainly a positive step in the right direction, there is a growing consensus at the FCC and in industry that America’s success at winning the “Race to 5G” will largely be driven by spectrum policy in the mid-band. With that goal in mind, the FCC has several proceedings (i.e., CBRS, L-Band License Modification, C-Band, 1675-1680 MHz NPRM) in front of them to bring more spectrum online in the mid-band category.

The critical importance of mid-band to 5G is no secret. What is less understood, however, is that mid-band is not simply a catch-all for spectrum between 1 GHz and 6 GHz. In fact, there are significant differences in spectrum propagation and technical operating parameters that influence the way specific bands in the 1-6 GHz category are deployed.

In the higher mid-band (2-6 GHz), there are larger blocks of spectrum (e.g., CBRS, C-Band, and BRS/EBS) that can provide wider channel sizes to enable high data speeds for a true 5G experience. Unfortunately, spectrum above 2 GHz has not been widely deployed in today’s 4G wireless networks. As a consequence, wireless infrastructure grids are not designed around the propagation characteristics of higher mid-band frequencies, making it relatively expensive to rapidly deploy these new, wider-channel bands on a sub-2 GHz network grid. The optimal use for this band is to have it deployed in a way that leverages its core attribute – delivering high-speed throughput.

Lower mid-band (1-2 GHz) spectrum, by contrast, enjoys favorable propagation and in-building penetration characteristics that enable broad-based mobile coverage. New technologies like supplemental uplinks and carrier aggregation can support combined use of lower mid-band and higher mid-band to deliver more bandwidth across a greater coverage area. A 2019 Nokia 5G technical study finds that “[s]uperior propagation characteristics of lower mid-band spectrum improve 5G coverage, both outdoor and indoor, as compared to 5G coverage when using only higher mid-band spectrum.” For example, “[a] cell site utilizing [a] Ligado uplink band can cover an area roughly 4.8 times greater than C-band.”

The benefits of combining these two spectrum categories to improve 5G performance underscore the importance of answering the industry’s call for an “all of the above” spectrum policy. Increasing spectrum availability in the lower mid-band—when combined with wider channel bands in higher mid-band—provides the best of both worlds: favorable signal propagation that enables the use of wider channels on a sub-2 GHz network grid. Similar to the rapid rollout of 4G a decade ago, re-use of existing wireless infrastructure and spectrum availability in all of the mid-band will ensure swift and economical network deployment to advance U.S. efforts to win the “Race to 5G.”

It’s time for the FCC to take action on all mid-band spectrum proceedings—advancing not only Ligado’s L-Band License Modification and the 1675-1680 MHz NPRM, but also those in CBRS and the C-Band. Once these FCC spectrum actions are taken, industry players can accelerate their 5G technology deployment plans. For Ligado, this means working with critical vendor partners like Nokia and Ericsson to deploy our planned 5G services.


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