A cellular radio access network comprising a plurality of radio transceivers geographically spaced so that neighbouring transceivers provide overlapping radio coverage for mobile user terminals, and a radio transceiver controller geographically spaced from and coupled to said plurality of radio transceivers, the controller being arranged to control each radio transceiver so that neighbouring transceivers can be configured to communicate with user terminals using either the same or different radio channels, whereby the effective cell sizes of the radio access network can be dynamically increased or decreased depending upon the demands placed on the available radio resources.