A signalling method in a frame-based wireless communication system allowing a base station (BS) to inform fixed or mobile subscriber stations (MS) of resource allocations without excessive signalling and processing overhead. In one embodiment, in addition to normal resource allocation information such as a DL-MAP or UL-MAP, IDs of MSs or connections, for which the resource allocation has been modified, cancelled, or initialized, are listed at the start of the frame so that each MS can identify itself (or its connection) in the list. Only those mobile stations for which the list is relevant need to act on the resource allocation information. In another embodiment, the BS attaches a period of validity to each allocation of resources which is transmitted along with the normal resource allocation information. This frees the BS from having to repeat the same information in subsequent frames, and each MS can go on using the same resource during the period of validity without needing to check for updates.