A device comprising: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the device to: receive, from a network device, signalling indicating a threshold priority for each logical channel and/or for each control element of a set of logical channels or control elements; select a subset of data units with a channel access priority higher than or equal to the threshold priority according to a descending order of a plurality of channel access priorities associated with the plurality of data units and with a predetermined number of data units with highest channel access priorities from a set of data units for multiplexing into a data packet such that a utilization of a transport block for the data packet is equal to or higher than a threshold utilization and such that amount of padding in the data packet is below a threshold amount, wherein the threshold priority for a logical channel or for a control element in the subset of data units indicates the lowest priority level of other logical channels or control elements in the subset of data units; multiplex the subset of data units into the data packet; and transmit the data packet. at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code configured to, with the at least one processor, cause the device to: receive, from a network device, signalling indicating a threshold priority for each logical channel and/or for each control element of a set of logical channels or control elements; select a subset of data units with a channel access priority higher than or equal to the threshold priority according to a descending order of a plurality of channel access priorities associated with the plurality of data units and with a predetermined number of data units with highest channel access priorities from a set of data units for multiplexing into a data packet such that a utilization of a transport block for the data packet is equal to or higher than a threshold utilization and such that amount of padding in the data packet is below a threshold amount, wherein the threshold priority for a logical channel or for a control element in the subset of data units indicates the lowest priority level of other logical channels or control elements in the subset of data units; multiplex the subset of data units into the data packet; and transmit the data packet. receive, from a network device, signalling indicating a threshold priority for each logical channel and/or for each control element of a set of logical channels or control elements; select a subset of data units with a channel access priority higher than or equal to the threshold priority according to a descending order of a plurality of channel access priorities associated with the plurality of data units and with a predetermined number of data units with highest channel access priorities from a set of data units for multiplexing into a data packet such that a utilization of a transport block for the data packet is equal to or higher than a threshold utilization and such that amount of padding in the data packet is below a threshold amount, wherein the threshold priority for a logical channel or for a control element in the subset of data units indicates the lowest priority level of other logical channels or control elements in the subset of data units; multiplex the subset of data units into the data packet; and transmit the data packet.