The method includes following steps: 1) after the communication between transmission and reception end is build up, the reception end figures out the relevant balanced SNR according to modulation mode and error rate; 2) the reception end selects the available subchannel based on the message of channel state, at the time of ensuring the balanced SNR, figures out the required reception SNR, and then figures out the signal power required by transmit end according to the reception SNR of reception end and link consumption; the power value of transmitting signal is defined as control message of power PT, and is fed back to the transmit end through feedback channel; 3) the transmit end adjusts the transmitting power and signal based on the received power control message and label information of subchannel. |