US Patent 10567986 Back-off mechanisms for fair joint access of unlicensed sidelink

Aspects of the disclosure relate to back-off mechanisms for fair joint access of an unlicensed sidelink channel. Each sidelink device may perform independent and asynchronous listen before talk (LBT) of the unlicensed sidelink channel with a respective back-off timer initialized with a back-off value selected to provide fair access to the unlicensed sidelink channel by both active sidelink devices and other devices utilizing the unlicensed sidelink channel. In some examples, the back-off value may be selected based on an estimated number of active sidelink devices. The estimated number of active sidelink devices may be determined, for example, by monitoring distributed handshake signaling on the unlicensed sidelink channel.