Grandfathered Satellite Earth Sations and Radars

ES and radar
Map of Grandfathered Earth Sations and Federal Radar Sites, Courtesy of: CommScope 

Note on terminology: The broadcast spectrum that has been allocated for Nonexclusive Nationwide Licenses is referred to as “3650-3700 Megahertz” Radio Service by the FCC and as “3.65 Gigahertz” by the wireless industry. The FCC expresses all of its wireless services in terms of megahertz for continuity, even if the spectrum can be expressed as gigahertz. The assigned frequencies for most of the spectrum bands classified by the FCC are less than a gigahertz. The wireless industry has found it more convenient to use the gigahertz terminology. Depending on context, the NN band is referred to on this website both as 3650-3700 MHz and as 3.5 GHz.


About the 3650-3700 MHz Service

In 2005, the Commission adopted a non-exclusive licensing scheme for the band, in lieu of an unlicensed scheme that was originally proposed in April 2004. In reaching this decision, the FCC considered several factors, including the band’s encumbrance with grandfathered satellite Earth stations and radiolocation operations, which will prevent new terrestrial use in major population centers along the east and west coasts of the Nation, and the lack of pairing opportunities with other spectrum for duplex operations.

This, as well as evidence that the band is well suited to high-power broadband operations, persuaded the Commission that much of the interest in developing the band is focused on smaller markets and less densely populated areas. For these reasons, the Commission structured the band’s rules to provide Wireless Internet Service Providers (WISPs) and other providers an economical means of quickly initiating broadband services, particularly in under-served and rural areas. The Commission concluded that this licensing approach struck an appropriate balance, providing a regime with low entry costs and minimal regulatory delay, while still ensuring more orderly operation than would exist under a traditional unlicensed approach in which users must accept interference from others in the band and users’ locations are unknown.

The Commission also designed the 3650 MHz band rules to provide flexibility for a variety of new terrestrial uses in order to encourage multiple entrants including a requirement that equipment operating in the band incorporate a contention-based protocol to minimize interference. The Commission concluded that contention-based protocols are well suited to avoiding interference among the multiple users that seek to use the band simultaneously.

Under the Commission’s rules, contention-based protocols can be broadly categorized as either “unrestricted” or “restricted.” Unrestricted protocols are broadly compatible and function to prevent interference even with other, dissimilar contention technologies on the market. Restricted contention protocols can prevent interference only with other devices incorporating the same protocol. The Commission, through the equipment certification process, retains the authority to determine whether equipment that operators seek to deploy in the band meets the requirements established for contention-based protocols.

As a further means of promoting effective shared use of the spectrum, all 3650 MHz licensees must cooperate and “make every effort” to avoid harmful interference and the FCC specifically declined to give interference priority to licensees who are the first to deploy in an area. To facilitate the negotiations that must accompany the cooperative use of the band by multiple entrants, the Commission requires that all 3650 MHz band licensees register their fixed and base stations in a common database, i.e., the Universal Licensing System.

The Commission also adopted a number of provisions to protect grandfathered satellite Earth stations, which retained their primary status, against interference from the newly authorized operations in the band. Specifically, the Commission created 150 km circular protection zones around approximately 100 grandfathered FSS Earth stations and prohibited terrestrial operations in the band within these zones, absent agreement with the affected satellite operators. Additionally, requests to register base or fixed stations within the 80 km circular protection zones established around each of three Federal Government radiolocation stations will only be approved upon successful coordination by the FCC with NTIA.

To provide further protection to the grandfathered earth stations, the Commission set maximum permissible power levels for both mobile and fixed or base stations operating in the band and required that mobile units be configured to transmit only when they could receive an enabling signal from a licensed base station. See Public Notice DA 07-4605 (pdf) for the filing procedures that detail the licensing and the fixed and base station registration process.