A method and an apparatus are described for increasing the flexibility of uplink resource allocation for a mobile station (MS) (100), that is backwards compatible with earlier standards that provide only a single data flow per MS. The method includes steps of (A) associating an allocated uplink resource (an Uplink State Flag (USF)) with one or more Temporary Block Flows (TBFs) for a Packet Data Channel (PDCH), and not with a MS per se (although a given USF is associated with only a single MS); and (B) using a Temporary Flow Identity (TFI) for identifying a TBF, where a TFI may be unique to a PDCH and, if not, is unique with respect to the MS on a PDCH (and hence with respect to the USF). The result is that the MS is enabled to send any of its TBFs on allocated resources of the same PDCH. An uplink resource may be allocated to the MS dynamically using the Uplink State Flag (USF) or by using a fixed allocation. A total of n Radio Bearers are associated with a single TBF, where n≧1.