Spectrum Sharing Has Broadened

Spectrum sharing emerged as a tool to enable TV White Spaces, Expanded with Citizens Broadband Radio Service and now is becoming an enabler for sharing 4G and 5G spectrum on the same cell towers and cell sites. As envisioned to enable data networks using former TV broadcast spectrum, the idea was that cognitive radios would sense what spectrum is available in any local area by interrogating a data base. 

In a CBRS application the same general principles allow sharing of resources not in use by the primary license holder. When the primary licensee is not using its resources in a local area, others may acquire secondary licenses. If any resources remain unused after primary and secondary licensees, spectrum can be used as would Wi-Fi, in a best-effort, contention-based mode. 

In a new use case, dynamic spectrum sharing allows a 5G mobile device to use 4G and 5G resources at a radio site.