The present invention provides a method, a radio base station (40) and a mobile terminal (50) for allocating resources in a telecommunications network, where communications between the radio base station (40) and the mobile terminal (50) take place over a plurality of carriers. The method comprises transmitting and receiving a resource allocation message comprising one or more bits. Each of the bits corresponds to a number of resource blocks, where the number is determined from the ratio of the aggregate bandwidth of the plurality of carriers divided by the bandwidth of the carrier over which the resource allocation message is sent.