Today’s hyper-connected world is driving explosive network growth as 5G adoption continues at a frenetic pace. Plans for the rollout of 5G-Advanced and 6G networks are already heating up, even as many network service providers are still deploying mid-band 5G spectrum. Anticipating this future growth, some industry pundits suggest that the U.S. mobile industry will exceed available network capacity soon without more spectrum allocations.

Before making any hasty decisions, perhaps we should take a step back and realistically evaluate the current and future state of affairs.

Spectrum Scuffles

Two U.S. Congress members recently introduced legislation requiring the Federal Communications Commission (FCC) to auction at least 600 megahertz of spectrum between 1.3 and 13.2 GHz within three years and at least 1,250 megahertz of spectrum within six years. The proposed bill, known as the Spectrum Pipeline Act of 2024, also would direct the National Telecommunications and Information Administration (NTIA) to identify at least 2,500 megahertz of mid-band spectrum to reallocate from federal use to commercial wireless services within the next five years.

Likewise, the industry trade organization 5G Americas recently published a white paper that calls for a comprehensive roadmap to introduce new commercially available spectrum to support the rollout of 5G-Advanced and future 6G networks. However, the 5G Americas white paper focuses on the upper mid-band spectrum, ranging from 7.125-15.35 GHz, noting that “more spectrum helps ensure effective deployment of future networks and drive the emergence of groundbreaking technologies.”

These plans presuppose that more spectrum is indeed required for wide-area 5G networks and not for private networks using unlicensed frequency bands such as the Citizens Broadband Radio Service (CBRS).

5G Coverage Evolution

However, it would take some time for these new spectrum bands to be available for cellular networks, while the current 5G networks should evolve to meet the various needs for capacity and bandwidth. As 5G technology evolves to embrace cloud-native architecture and mid-band frequencies, mobile network operators (MNOs) are changing the way they plan and deploy their networks. At the same time, traditional macro cell sites are reaching saturation, pushing MNOs to densify 5G networks by building out small cells. This small cell approach provides additional 5G coverage, capacity, speed, and performance more quickly and efficiently — particularly in high-traffic urban and suburban areas.

With small cells covering shorter distances, these network architectures use the available spectrum more effectively to meet escalating demands for higher speeds, greater bandwidth, and lower latency. By serving smaller coverage areas located closer to subscribers, small cells can reuse the same frequencies more often, increasing network capacity without radical increases in spectrum allocation. This is not to say that no new spectrum will ever be required. New spectrum for 6G and beyond will be necessary, opening opportunities to drive new innovation.

As the steady drumbeat calling for more spectrum gets louder, it’s important to remember that the journey from 5G to 6G and beyond will be a marathon, not a sprint.

Capacity Where It Is Needed

Considering that 80 percent of all mobile traffic occurs indoors, perhaps the current focus should be on how much spectrum is needed for in-building communications and how it can be used most effectively. Just as small cells are used in the outdoor network to densify network capacity, in-building wireless networks using small cells, distributed radios, and distributed antenna systems (DAS) can deliver dedicated capacity and coverage indoors.

These in-building wireless solutions offload the capacity demanded of the outdoor network, mitigating or at least delaying the need for additional spectrum. Until radio and antenna technologies catch up to the physical limitations imposed by higher frequency spectrum, reaching above 6 GHz is impractical for wide area coverage and unnecessary for indoor coverage, with some exceptions such as very high capacity venues like stadiums and arenas.

Sustainable Frequencies

Spectrum above 6 GHz is incredibly expensive to deploy and operate due to poor propagation. It is not currently sustainable, requiring significantly higher transmit power than lower frequencies. Densifying the network by deploying in-building networks with sub-6 GHz spectrum is more cost-effective. The most attractive large chunk of new spectrum under consideration for mobile networks in the U.S. is 3100-3450 MHz. While this spectrum is also used by the Department of Defense, CBRS has proven the concept of shared spectrum with a priority access system and interference mitigation methods.

A modular platform like the SOLiD ALLIANCE 5G DAS supports a huge amount of bandwidth from all the major MNOs, providing access to plenty of in-building capacity with the currently available 5G spectrum. The key is proper network planning and design to allocate sufficient sector density with the available frequencies.

For help designing a robust DAS system that makes the most of the available spectrum for outstanding in-building performance, contact the experienced SOLiD Engineering and Design services team. To learn more, visit: www.solid.com/us/services/engineering-and-design.