A method of scheduling data for transmission over the air interface of a wideband code division multiple access network, said data being transported over the air interface on a downlink shared channel. The method comprises receiving data in the form of IP packets at a radio network controller, segmenting said IP packets into protocol data units, and forwarding said protocol data units from the radio network controller to a radio base station serving one or more user terminals. The radio network controller identifies to the radio base station the protocol data units belonging to a common IP packet. At the radio base station, each protocol data unit is scheduled for transmission over the air interface in dependence upon the IP packet to which it belongs.