Contention resolution window size based on uplink carrier switching

A wireless device comprising:

• one or more processors;
• and
• memory storing instructions that, when executed by the one or more processors, cause the wireless device to:
• receive one or more radio resource control (RRC) messages comprising configuration parameters of a first uplink carrier and a second uplink carrier of an unlicensed cell;
• based on switching from the first uplink carrier to the second uplink carrier and a priority class of a listen-before-talk (LBT) procedure for a first transmission of a transport block on the second uplink carrier, determine a contention window to be a minimum contention window of a plurality of contention windows for the LBT procedure;
• and
• transmit, via the second uplink carrier, the transport block based on the LBT procedure using the contention window.

A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of a wireless device, cause the wireless device to:

• receive one or more radio resource control (RRC) messages comprising configuration parameters of a first uplink carrier and a second uplink carrier of an unlicensed cell;
• based on switching from the first uplink carrier to the second uplink carrier and a priority class of a listen-before-talk (LBT) procedure for a first transmission of a transport block on the second uplink carrier, determine a contention window to be a minimum contention window of a plurality of contention windows for the LBT procedure;
• and
• transmit, via the second uplink carrier, the transport block based on the LBT procedure using the contention window.