ATPC also works in conjunction with the ACM mechanism to increase transmit power with modulation levels changes. The atpc max_power command allows setting the individual maximum power levels for each modulation level from QPSK to QAM256. ATPC has Step Size and Max Power settings to limit the output power of the unit and prevent a violation of the license.
Note: The user set transmit power setting cannot be changed after ATPC is enabled. To manually change the power setting, ATPC needs to be disabled.
ATPC Max Power & Step Size
Settings for ATPC Max Power and the ATPC Step Size control how the ATPC function will behave while attempting to achieve the targetRSSI. ATPC Max Power is the maximum power setting ATPC can set the power output to when trying to reach the TargetRSSI. ATPC Step Size is the power level change in dB that ATPC can change power output. Larger step sizes result in faster response to fading conditions.
Transmitter Maximum Power Output
Maximum transmitter power output is dependent on the band of operation and the modulation level. Both the AP1 and AP2 models have the same default maximum power levels for each band and modulation. AP1/HP1 models can be set to higher transmit power levels for some frequencies when the Power License Key (AP‐KE‐3) is enabled.
Consult the datasheet for your product to determine the maximum transmit power and set no higher than specified on the datasheet or allowed by your license.
There is no dependency on the channel bandwidth used within a particular band. As an example, the power level for QAM256 within the 6 GHz band is the same for 3.5 MHz channels as it is for 56 MHz channels. The datasheet illustrates this and shows the maximum set power levels for each model family, band, and modulation level.
When ATPC is active, the atpc_max power should be set to the maximum power for each modulation used if adaptive power changes are desired with ACM modulation changes. If the power level is to remain constant across ACM modulation changes, all atpc_max power levels should be set to the max power of the highest modulation level, typically 256QAM.
If ATPC is off then the power will not be changed under any circumstance and will remain at the level set by the operator.