Patent ID: 8462877

Claim:
A method of transmitting multimedia broadcast/multicast data based on hierarchical modulation, comprising: determining whether the data is transmitted for a first time and if yes, modulating the data with a first constellation map in an order from a basic layer to an enhanced layer and then transmitting the data; and receiving a check report returned from a receiver, determining whether the check report indicates there are both basic layer and enhanced layer data errors and if yes, exchanging last two bits of the enhanced layer and first two bits of the basic layer and modulating the data with a second constellation map and then transmitting the data, and if no, determining whether the check report indicates there is only the basic layer error and if yes, modulating the data with the second constellation map in the order from the basic layer to the enhanced layer and then transmitting the data, otherwise exchanging the last two bits of the enhanced layer and the first two bits of the basic layer and modulating the data with the first constellation map and then transmitting the data; wherein the method further comprising: before the step of determining whether the check report indicates there are both basic layer and enhanced layer data errors, a retransmission times counting step of counting the retransmission times of the data and if the retransmission times exceed a preset threshold, the procedure ends; otherwise the procedure proceeds to determining whether the check report indicates there are both basic layer and enhanced layer data errors.