A method for operating a radio node for a wireless communication network, the radio node being adapted for Licensed-Assisted Access, LAA, and for transmitting communication data on at least one secondary carrier of a carrier aggregate, CA, based on a timing relative to a pre-defined time structure defined to synchronize the radio node with one or more other radio nodes, wherein the pre-defined time structure is defined by subframes, the method comprising: - defining at least one freeze interval relative to the pre-defined time structure, wherein each freeze interval is an interval comprised in a subframe in which no transmission of communication data may be started; - defining at least one transmission start interval relative to the pre-defined time structure, wherein each transmission start interval is an interval comprised in a subframe in which transmission of communication data may be started; - defining at least one clear channel assessment, CCA, budget, wherein each CCA budget is a time interval in which Listen-Before-Talk, LBT, procedures may be performed, and wherein each CCA budget overlaps with at least one of the freeze intervals; - performing a Listen-Before-Talk, LBT, procedure during one of the CCA budgets to determine whether accessing the at least one secondary carrier for transmission is allowed; - if accessing the at least one secondary carrier for transmission is determined, during one of the transmission start intervals, to be allowed based on performing the LBT procedure, starting transmission of communication data on the at least one secondary carrier in the transmission start interval; and - if accessing the at least one secondary carrier for transmission is determined, during one of the freeze intervals, to be allowed based on performing the LBT procedure, delaying starting transmission of communication data on the at least one secondary carrier to start transmission of communication data on the at least one secondary carrier outside the freeze interval. - defining at least one freeze interval relative to the pre-defined time structure, wherein each freeze interval is an interval comprised in a subframe in which no transmission of communication data may be started; - defining at least one transmission start interval relative to the pre-defined time structure, wherein each transmission start interval is an interval comprised in a subframe in which transmission of communication data may be started; - defining at least one clear channel assessment, CCA, budget, wherein each CCA budget is a time interval in which Listen-Before-Talk, LBT, procedures may be performed, and wherein each CCA budget overlaps with at least one of the freeze intervals; - performing a Listen-Before-Talk, LBT, procedure during one of the CCA budgets to determine whether accessing the at least one secondary carrier for transmission is allowed; - if accessing the at least one secondary carrier for transmission is determined, during one of the transmission start intervals, to be allowed based on performing the LBT procedure, starting transmission of communication data on the at least one secondary carrier in the transmission start interval; and - if accessing the at least one secondary carrier for transmission is determined, during one of the freeze intervals, to be allowed based on performing the LBT procedure, delaying starting transmission of communication data on the at least one secondary carrier to start transmission of communication data on the at least one secondary carrier outside the freeze interval.