One aspect of this disclosure provides an apparatus for wireless communication. The apparatus comprises a low noise amplifier (LNA), an attenuator, and a processing system. The attenuator is configured to receive a signal from the LNA, generate a first attenuated signal based on the received signal, and generate a second attenuated signal based on the received signal. The processing system is configured to measure a first signal strength of the first attenuated signal at a position and measure a second signal strength of the second attenuated signal at the position. The processing system is further configured to determine a first value based on the first signal strength and the second signal strength and determine a second value based on the first attenuated signal and the second attenuated signal. The processing system is also configured to adjust a current of the LNA if the first value exceeds the second value.