A wireless device (30) receives control information (28) that jointly encodes respective values for two or more channel access parameters. The two or more channel access parameters govern performance by the wireless device (30) of a listen-before-talk, LBT, procedure prior to an uplink transmission (32) in a radio resource allocation (34). In some embodiments, a mapping (40) maps different indices to different combinations of values for the two or more channel access parameters. In this case, the control information (28) may comprise an index mapped by the mapping (40) to one of the different combinations of values for the two or more channel access parameters. Regardless, the wireless device (30) may perform the LBT procedure (or not) according to the received control information (28).