There has been a lot of talk lately about spectrum sharing – Spectrum Access Systems, Dynamic Spectrum Arbitrage, Environmental Sensing Capability, Shared Spectrum Access for Radar and Communications, to name just a few of the discussed approaches. The purveyors of these techniques believe that their technology will change the way spectrum is shared and will solve the nation’s unquenchable thirst for this finite resource. We have some reluctance about these high-tech approaches because they largely remain unproven. We’ve certainly never seen any one of them working in a commercially deployed wireless network serving 100 million plus customers; and we don’t think we will for some time.
But we have been thinking a lot about spectrum sharing, particularly in light of the FCC proceeding that proposes that satellite operations share spectrum with terrestrial mobile broadband services to advance 5th generation networks. In support of that proceeding, we recently collaborated with EchoStar – a premier broadband satellite company – on developing a sharing framework that will enable both satellite and mobile services to make intensive and productive use of valuable high GHz 5G spectrum resources in a manner that does not unduly restrict the development of either service. How? Not with some new-fangled technology with an acronym. We talked with each other to understand interference concerns and to develop a coordination framework that would work for both types of services.
In our discussions with EchoStar, we found that we not only shared common business goals and interests, but that our network architectures were a lot more compatible than once believed. For example, satellite earth stations point into the sky with highly directional antennas and mobile broadband base stations typically point their antennas towards the ground. We also learned that it is not necessary for earth stations to be in densely populated urban centers, where mobile broadband is used the most. With these and other data points, we outlined a reasonable set of coordination guidelines and parameters that would allow us to deploy mobile networks and new earth stations in more places than previously thought.
The framework was developed around some high-level goals. First, a commitment to protect existing satellite earth stations from interference. Second, that new satellite earth station installations would need to protect the new mobile broadband systems – especially in the nation’s most densely populated urban areas. Protection zones were proposed around those dense urban cores. Lastly, we agreed that coordination criteria needs to be developed to give both satellite operators and mobile broadband service providers enough information to begin coordination discussions on the same footing.
The key to any successful coordination is a good faith approach accompanied by clear rules for both parties. The coordination guidelines being developed will be based on both. The framework proposes that FCC rules should require mobile broadband operators to respond to coordination requests from satellite operators and enter into negotiations in good faith. We believe this common sense approach – which has been used in the wireless industry for decades – can be implemented much faster and will have a more predictable outcome than some new Dynamic Frequency Allocation Shared Spectrum Algorithm that has yet to be invented much less tested or deployed.
We look forward to continuing to work collaboratively with the FCC and the satellite industry as we seek to formalize a set of rules to allow for the most effective use of the bands for both industries.