Every few years the next “generation” of commercial broadband systems is developed, each requiring the electromagnetic spectrum (EMS). The first generation (1G) systems introduced in the mid-1980s enabled unprecedented mobile communication through the implementation of cellular networks. Each subsequent generation — 2G, 3G, 4G, 5G, 6G and beyond — continues to introduce greater capability to mobile broadband consumers. Enabling each generation often includes new requirements for EMS use.
The EMS consists of all frequencies and is subdivided into many smaller frequency bands. Each band is allocated for various types of service. When new technology requires access to spectrum, one or more of these frequency bands may need to be reallocated to add the type of service required by the new technology. For example, a new radar may require a new radiolocation allocation in a frequency band previously only allocated for mobile radio communications. Spectrum reallocation is complex, expensive, and often takes decades for incumbent technology in the band to accommodate the new technology by either sharing with that new system or relocating to another band.
Different frequency bands have unique advantages and disadvantages. Lower frequencies tend to travel farther and spread out to cover a large area, but they require larger antennas and higher power to transmit and carry less data than higher frequencies. Higher frequencies can carry larger amounts of data, but they tend to be highly directional and are often blocked by obstacles like trees, buildings, and even rain. Additionally, some frequency bands have very special characteristics, such as reflection off layers in the atmosphere or sensitivity to changes in atmospheric moisture. The result is that certain parts of the spectrum are better suited to some uses than other parts of the spectrum.
Each new broadband generation enables new capabilities, which often require additional spectrum beyond what is currently allocated. Because spectrum is a finite resource, existing allocations should be exhausted before additional spectrum frequency bands are reallocated.
The Department of the Navy works closely with the National Telecommunications and Information Administration (NTIA) to be an efficient and effective federal spectrum user. The Federal Communications Commission (FCC) works with non-federal spectrum users such as next generation commercial broadband providers to effect the same diligence. Because much of the spectrum is shared between federal and non-federal users, the FCC and NTIA must work together closely to ensure that all spectrum is used efficiently and effectively. Together, through careful management of the EMS, federal and non-federal spectrum users can continue to benefit from new technologies, including next generation broadband systems.
Tom Kidd is the director for DON Strategic Spectrum Policy in the Office of the Department of the Navy Chief Information Officer.