A method of scheduling an uplink (UL) data packet on a packet data network (PDN) connection of at least one radio bearer by a wireless communication unit comprises receiving, by the wireless communication unit, a signalling message comprising at least one scheduling priority parameter assigned to at least one uplink radio bearer, wherein the at least one scheduling priority parameter is based on at least one characteristic of the PDN connection that the radio bearer belongs to. The method further comprises determining, from the at least one scheduling priority parameter, at least one user transmission priority level associated with at least one PDN connection of at least one radio bearer; and scheduling at least one uplink data packet transmission in response to the at least one user transmission priority level.