Apparatus and method for resource allocation for multicast data in broadband wireless access system

An apparatus for resource allocation for multicast data in a wireless access system, the apparatus comprising:

• a scheduler for scheduling multicast packets and outputting changed information if a change of resource allocation information is necessary for each multicast ID;
• and a resource allocation message generator for generating, upon receipt of information of a user group using the multicast ID from the scheduler, a second multicast resource allocation message including the received user group information and generating, upon receipt of information transmitted in common to users of the user group, a fast multicast resource allocation message including the information transmitted in common, wherein the second multicast resource allocation message includes at least one of a Header field that indicates the type of the resource allocation message, a MulticastID field that indicates an index representing a user group receiving the same multicast data, a Media Access Control ID (MACID) field that indicates an ID managed by a base station for discrimination between users of the user group, a MACID flag field that represents an indicator for indicating the new allocation or the deallocation of a MACID allocated to a multicast ID, and a Cyclic Redundancy Check (CRC) field that is used to check if there is a channel decoding error.