The electromagnetic spectrum refers to properties in air that can transmit electrical signals. The spectrum spans from radio waves to gamma rays. Within this spectrum, we can see visible light and feel the heat of infrared radiation. However, there are certain wavelengths we cannot detect but have nevertheless put to use. WiFi, for example, runs on the 2.4–5 GHz radio band. Physicians use X-Rays to see inside bodies and gamma rays to kill cancer cells.
Certain frequencies, such as those used for WiFi under 802.11 standards, are designated for specific purposes and have no individual or organization owning an exclusive license to use the frequency. Thus, it is possible for WiFi signals to interfere with each other. As your neighbor places more and more access points closer to your router, you can expect a steadily worsening internet connection. By contrast, certain other spectrum is exclusively licensed to designated providers, thereby eliminating the possibility of interference.
The recent deployment of millimeter wave (mmWave) technology by major U.S. wireless carriers on 5th-generation mobile networks (5G) creates exciting opportunities for modern applications. Operating just above the microwave band, mmWave covers electromagnetic frequencies from 30–300 GHz. Theoretically, with mmWave technology, 5G can offer dramatically higher data transfer speeds and lower latency than what was possible with 4th-generation mobile networks. Electrical engineers have hypothesized that a reliable nationwide high-speed wireless network could enable the development of many technologies relying on machine-to-machine communications (the “Internet of Things” paradigm), such as autonomous aerial vehicles, advanced robotics, 3D videos, automotive radars, cloud computing, and radio astrology.
However, the deployment of mmWave technology faces technological and legal impediments. Most prominently, mmWave is more susceptible to blockage and impedance than lower-frequency wavelengths. It also has greater path loss and is more easily attenuated (by buildings, foliage, or even rain). Practically, this means that wireless signals are more easily blocked in high-density urban environments where 5G technology is often used.
Thus, to increase 5G accessibility, major U.S. carriers can increase the amount of exclusive spectrum they hold by purchasing licenses from the Federal Communications Commission (FCC), or they can increase their real estate holdings to locate more cell towers closer to their customers and even create “ultra-dense” networks.
In Title VI of the Middle Class Tax Relief and Job Creation Act of 2012 (Spectrum Act), Congress authorized the FCC to auction certain spectrum bands to the highest bidder. These auctions have raised billions of dollars for the US Treasury. In its most recent Spectrum Auction, Auction 103, the FCC received over $7.5 Billion in net bids to sell 14,142 licenses for $4.4 Billion. In its recent “C-band” auction (4–8 GHz), the FCC received over $81 Billion in gross bids for exclusive spectrum. The FCC once maintained “spectrum caps” to limit the amount of spectrum any one entity could hold, but the FCC withdrew these regulations in 2003. Thus, spectrum hoarding could pose a real problem in the near future, notwithstanding FCC auction rules “requiring the timely build-out of networks” once spectrum is acquired.
Because exclusive spectrum is inherently limited, major US wireless carriers have also invested in real estate to locate additional cell towers and other communications equipment closer to consumers. Accenture, a consulting firm, estimated that next-generation 5G technology will require telecommunications operators to invest $275 Billion in supporting infrastructure. However, community activists have raised concerns that cell towers and rooftop antennae can reduce property values by damaging neighborhood aesthetics. To access their equipment, carriers may demand a perpetual easement. This, combined with the potential nuisance value of a cellphone tower, can make property owners hesitant to lease land for tower assets. Nevertheless, the relative stability of payments from tower leases continues to be attractive to real estate investors. Moreover, the Telecommunications Act of 1996 prohibits local authorities from taking zoning actions that ban cell tower facilities in a particular area and clarified FCC jurisdiction to preempt state and local zoning authority. Thus, real estate transactions pose both challenges and opportunities for cell phone providers seeking to expand their 5G services.
Finally, additional investment in cell phone antenna systems (signal receivers) may mitigate the technological challenges posed by mmWave and similar technologies. Major carriers and cell phone manufacturers have invested in next-generation antenna systems to increase 5G spectrum efficiency. These investments, combined with spectrum and real estate acquisitions, should increase as cell phone carriers compete to build the best networks.
 https://about.att.com/pages/5g-plus.html; https://www.verizon.com/coverage-map/; https://www.sciencedirect.com/science/article/pii/B9780124186781000040; https://www.qualcomm.com/5g/what-is-5g; https://ieeexplore.ieee.org/document/9798820