Apparatus and method for multicast and broadcast service in broadband wireless access system

An apparatus of a base station in a wireless communication system, the apparatus comprising:

• a time controller for managing a broadcast start time and a broadcast end time and notifying a start of a broadcast service at a predetermined time before the broadcast start time;
• and
• a buffer controller for, upon being notified the start of the broadcast service from the time controller, restricting a buffer occupation of unicast traffic when available space of the buffer is less than a buffer size required by a broadcast service,
• wherein the predetermined time is proportional to the buffer size required by the broadcast service, and is inversely proportional to a traffic output rate from the buffer.

A method for operating a base station in a wireless communication system, the method comprising:

• determining, by a base station time controller, whether a current time is a predetermined time before a broadcast start time;
• determining, by a base station Connection Admission Control (CAC) processor, a capacity decrease due to broadcast service if the current time is the predetermined time before the broadcast start time;
• and
• updating, by the base station, an available capacity used for CAC using the calculated capacity decrease,
• wherein the capacity decrease due to broadcast service is proportional to radio resources allocated for the broadcast service, and is inversely proportional to total downlink radio resources.

A method for operating a base station in a broadband wireless access communication system, the method comprising:

• determining whether a current time is a predetermined time before a broadcast start time;
• if the current time is the predetermined time before the broadcast start time, comparing available space of a buffer with a buffer size required by the broadcast service;
• and
• restricting a buffer occupation of unicast traffic when available space of the buffer is less than the buffer size required by the broadcast service,
• wherein the predetermined time is proportional to the buffer size required by the broadcast service and is inversely proportional to a traffic output rate from the buffer.

An apparatus of a base station in a wireless communication system, the apparatus comprising:

• a timing controller for managing a broadcast start time and a broadcast end time, notifying a start of a broadcast service to a Connection Admission Control (CAC) processor at a first predetermined time before the broadcast start time, and notifying the start of the broadcast service to a buffer controller at a second predetermined time before the broadcast start time;
• the CAC processor for, upon being notified the start of the broadcast service from the time controller, calculating a capacity decrease due to broadcast service and subtracting the capacity decrease from a current available capacity to update the available capacity;
• and
• the buffer controller for, upon being notified of the start of the broadcast service from the time controller, restricting a buffer occupation of unicast traffic when available space of the buffer is less than a buffer size required by the broadcast service,
• wherein the capacity decrease due to broadcast service is proportional to radio resources allocated for the broadcast service, and is inversely proportional to total downlink radio resources.

A method for operating a base station in a wireless communication system, the method comprising:

• determining whether a current time is a first/second predetermined time before a broadcast start time;
• determining a capacity decrease due to broadcast service if the current time is the first predetermined time before the broadcast start time;
• and
• if the current time is the second predetermined time before the broadcast start time, restricting a buffer occupation of unicast traffic when available space of the buffer is less than a buffer size required by a broadcast service,
• wherein the second predetermined time is determined using the buffer size required by the broadcast service and a traffic output rate from the buffer.