Patent ID: 8111710

Claim:
A method for dynamically adapting a transmission condition of a base station for at least a multicast broadcast service flow transmitting to a plurality of subscriber stations at a current transmission level associated with a first modulation-and-coding scheme (MCS) level and a first transmission power, the method comprising: assigning a plurality of CDMA codes to a feedback corresponding to the multicast broadcast service flow; performing a transmission adapting process comprising: sending a multicast-poll message to the subscriber stations, wherein the multicast-poll message indicates a feedback condition of a new transmission level associated with a second MCS level and a second transmission power, the assigned CDMA codes and a feedback channel allocated for transmitting the feedback; adapting the current transmission level according to a feedback received status of the base station, wherein the feedback received status of the base station shows whether at least a NACK-based feedback is received from one of the subscriber stations, the NACK-based feedback is in a form of one of the assigned CDMA codes without containing any user-specific message and when the feedback received status of the base station shows at least a NACK-based feedback from one of the subscriber stations, which is unsatisfied with the feedback condition, is received, the current transmission level is maintained; updating the feedback condition under a circumstance that the feedback received status of the base station shows at least a NACK-based feedback from one of the subscriber stations, wherein: if the first transmission power is equal to the second transmission power and the first transmission power is smaller than a maximum transmission power for transmitting the multicast broadcast service flow, updating the new transmission level, which is indicated in the sent multicast-poll message, by maintaining the second MCS level and increasing the second transmission power; if the first transmission power is equal to the second transmission power and the first transmission power is equal to the maximum transmission power, updating the new transmission level, which is indicated in the sent multicast-poll message, by setting the second MCS level to be a less robust MCS level and maintaining the second transmission power; if the first transmission power is not equal to the second transmission power, updating the new transmission level, which is indicated in the sent multicast-poll message, by setting the second transmission power to be equal to the first transmission power and maintaining the second MCS level; updating the feedback condition according to the updated new transmission level; and repeating the transmission adapting process.