Patent ID: 8711764

Claim:
A method for transmitting Multicast/Broadcast Service (MBS) data by a Base Station (BS) in a communication system, the method comprising the steps of: receiving Channel Quality Information (CQI) from a plurality of Mobile Stations (MSs) receiving a same type of MBS data, wherein the plurality of MSs includes at least three MSs; detecting a first MS having a most inferior channel status among the plurality of MSs receiving the same type of MBS data, based on the received CQI; determining a Modulation and Coding Scheme (MCS) level for the MBS data based on the CQI received from the first MS; transmitting, to the first MS, a first message indicating to feed back CQI in a first period; transmitting, to all other MSs, except the first MS, among the plurality of MSs receiving the same type of MBS data, a second message indicating to feed back CQI in a second period, wherein the second period is configured to be longer than the first period; detecting a second MS, different from the first MS, as having the most inferior channel status based on the CQI received during the first period and the second period; and when the second MS is detected as having the most inferior channel status based on the CQI received during the first period and the second period, changing the MCS level based on the CQI received from the second MS, and transmitting information on the changed MCS level to the plurality of MSs; and determining MCS levels differently for different types of MBS data, and changing MCS levels each time an MS having a most inferior channel status for each of the types of MBS data changes.