A dynamic channel assignment scheme for a TDD radio communication system (100) with coexisting dedicated (230; 240) and shared (210; 220) channels has segregated dedicated and shared channel mechanisms. Up to n.sub.DL.sub.--.sub.DCH.sub.--.sub.MAX/n.sub.UL.sub.--.sub.DCH.sub.--.sub- .MAX dedicated downlink/uplink channel slots are granted, with the remainder of slots for shared channels. These maximum numbers accommodate the needs of conversational and streaming class traffic carried on shared channels. New slots can be claimed for dedicated channels (subject to this maximum) as required, taking the shared channel slot with the smallest timeslot. If the last DCH allocation in a slot is ended, the slot is freed for DSCH/USCH usage. This provides the following advantage(s): uplink algorithm metrics account for intercell interference, the most significant interference source in TDD mode systems, leading to greater capacity; midcall reallocation allows coverage and quality of service to a user to be maintained when a user moves from the centre of the cell to the cell edge; dynamic split between dedicated channel timeslots and shared channel timeslots allows the network to optimise radio resources according to traffic type, leading to an overall higher capacity when the network supports both dedicated channels and shared channels; alignment of the DCH slots across many cells improves the usefulness of measurements for DCA/CAC.