A method and an apparatus are disclosed whereby a base station generates a resource allocation Information Element (IE) including an allocation period for persistent allocation and resource allocation information indicating a persistent resource, loads the IE on a map message, and then transmits the map message to a mobile station. The number of Automatic Repeat reQuest Channel Identifiers (ACIDs indicating the number of HARQ channels used for an HARQ operation is calculated based on the maximum retransmission delay for the HARQ operation and the allocation period acquired from the resource allocation IE. Therefore, the present invention minimizes the map overhead for resource allocation according to the persistent allocation scheme.