Method and system for managing base station transmissions responsive to invocation of high-order modulation scheme communications

A base station comprising:

• a wireless communication interface through which the base station serves over an air interface wireless communication devices (WCDs), wherein the wireless communication interface includes a power amplifier and transmit antennas, and wherein the base station has a configuration in which the base station is currently set to engage in downlink transmission at a maximum total transmit power level supported by the power amplifier and using a particular quantity of the transmit antennas, whereby the maximum total transmit power level is distributed among the particular quantity of the transmit antennas;
• and
• a controller including one or more processing units, non-transitory data storage, and program instructions stored in the data storage and executable by the one or more processing units to carry out operations including:
• determining that each of at least one WCD currently being served by the base station is configured to support a particular modulation scheme;
• and
• responsive to the determining, (i) changing the configuration so that the base station is currently set to engage in downlink transmission at a reduced maximum total transmit power level and using fewer than the particular quantity of the transmit antennas, whereby the reduced maximum total transmit power level is distributed among the fewer transmit antennas, and (ii) engaging in downlink transmission using the reduced maximum total transmit power level and the fewer transmit antennas.