An AP 1300 may decrease transmit power of the TPC STA 1320 for the fairness of the communication resource distribution between the non-TPC STA 1340 and the TPC STA 1320. If the transmit power of the TPC STA 1320 is decreased, the transmit coverage of the TPC STA 1320 may be decreased, and an interference for the non-TPC STA 1340 may be decreased. That is, the AP 1300 may control the transmit power of the TPC STA 1320, and an uplink frame of the TPC STA 1320 sensed by the non-TPC STA 1340 may be decreased. Therefore, a Tx opportunity of the non-TPC STA 1340 may be relatively increased.

The transmit power may be decreased along with an increase in a CCA threshold (or CCA level). For example, if a difference between the CCA threshold is xdB, the transmit power may be decreased by xdB by applying the difference of the CCA levels to the transmit power. Alternatively, the transmit power may be determined on the basis of a function in which the difference between the CCA thresholds is used as an input value.

For example, a transmit power level P may be f(x)+a. f(x) may be a function in which a difference between CCA thresholds is used as an input value, and ‘x’ may be a difference between CCA thresholds between the TPC STA 1320 and the non-TPC STA 1340. ‘a(chǎn)’ may be a system variable determined on the basis of the number of STAs in a BSS or a BSS range.

For example, if a CCA threshold of the non-TPC STA 1340 is ?82 dBm and a CCA threshold of the TPC STA 1320 is ?72 dBm, the transmit power level of the TPC STA 1320 may be determined to have a difference of 10 dB with respect to the transmit power level of the non-TPC STA 1340, and may be determined to have a difference of 0 to 10 dB by considering another system variable.