A receiver operates to AGC a multi-carrier signal through a corresponding number of inner loops and an outer loop AGC processes. A first number of bits for representing the multi-carrier signal with a limited amount of interference is determined through a calibration mode process. The first number of bits provides for quantization of the multi-carrier signal at an outer loop AGC to a maximum quantization level. After the received signal power estimate is reached a predetermined “ON” threshold, the outer loop AGC is operated at a second number of bits higher than the first number of bits to allow a quantization of possible interference in accordance with a difference of the first and second number of bits. The outer loop AGC switches back to use the first number of bits when the received signal power estimate falls below a predetermined “OFF” threshold.