US frequency rights for non-geostationary satellites are being reformed. The industry has long argued about what operators of such satellites should do when mutual interference occurs on shared frequencies. This particularly affects the large near-Earth satellite fleets of SpaceX (Starlink) and Oneweb, as well as potential new entrants such as Amazon.com (Kepler) and Telesat Canada. On Friday, the regulatory authority FCC (Federal Communications Commission) published a new regulation (FCC 23-29) that incorporated the results of a consultation.
The new document does not yet answer all the detailed questions, but sets out three basic rules: First, all satellite operators must negotiate procedures for sharing spectrum with each other in good faith. If they don’t, the FCC threatens fines, license restrictions and even license revocation.
Secondly, the current procedure for dividing the frequency spectrum in the event of interference will be continued with a technical modification – but it will only apply to satellites whose radio licenses were allocated at the same time, i.e. in the same allocation round. Because, thirdly, earlier licensed satellites now have priority over later licensed ones. The latter have to show in their application for radio frequency rights how they intend to respect the radio rights of other operators’ satellites that have already been approved.
Here, however, the FCC sets a time limit: The subordination for newcomers is only valid for ten years from the date on which their license came into force. After that, the older operators lose their priority, which then automatically threatens division: If the joint use of frequencies does not work without notable impairments, the frequencies are divided. And that usually means a loss of transmission capacity for everyone involved.
Further consultation
The technical modification mentioned concerns the way in which interference is calculated. Previously, there was a threshold of a maximum six percent increase in noise temperature before frequencies were split. In the future, the deterioration in data throughput should decide instead. The authority would like to find out exactly which limit value should apply in a further consultation. There are three percent in the room, interested parties can express their opinion until the beginning of June.
It should also be discussed how to proceed if several satellite systems interfere with each other. Finally, the FCC asks if there should be special rules for cooperation once the ten-year seniority period for older operators has expired.
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