Determining channel occupancy for sidelink communication

A system, comprising:

• at least a first terminal device;
• and
• at least a second terminal device configured to transmit a first transmission to the first terminal device,
• wherein the first terminal device is configured to:
• receive the first transmission from the second terminal device;
• measure a first channel busy ratio;
• determine a first channel occupancy ratio based at least partly on the received first transmission;
• update the first channel busy ratio based at least partly on the determined first channel occupancy ratio and the measured first channel busy ratio, wherein the first channel busy ratio is updated by subtracting at least a part of the determined first channel occupancy ratio from the measured first channel busy ratio;
• and
• determine a first channel occupancy ratio limit based at least partly on the updated first channel busy ratio and a first sidelink transmit power of the first terminal device.

A method, comprising:

• receiving, by a first terminal device, a first transmission from a second terminal device;
• measuring, by the first terminal device, a channel busy ratio over a first time window;
• determining, by the first terminal device, a channel occupancy ratio based at least partly on the received first transmission;
• updating, by the first terminal device, the channel busy ratio based at least partly on the determined channel occupancy ratio and the measured channel busy ratio, wherein the channel busy ratio is updated by subtracting at least a part of the determined channel occupancy ratio from the measured channel busy ratio;
• determining, by the first terminal device, a channel occupancy ratio limit based at least partly on the updated channel busy ratio and a sidelink transmit power of the first terminal device.