1. A method for computing a gain control metric for a wireless repeater in a wireless communication system, the wireless repeater having a first antenna and a second antenna to receive a receive signal and transmit an amplified signal, the receive signal being a sum of a remote signal to be repeated and a feedback signal resulting from a feedback channel between the first and second antenna of the wireless repeater, the feedback channel thus forming a feedback loop between the first and second antennas, the method comprising: receiving a gain control input signal from a repeater circuitry of the repeater, the gain control input signal being taken from any point in the feedback loop of the repeater; downsampling the gain control input signal at a first downsampling rate; computing a correlation term for each of desired channel taps, the correlation term being indicative of a correlation of the gain control input signal and a delayed version of the gain control input signal; computing a normalization term, the normalization term being indicative of a power of the gain control input signal that is not delayed; downsampling the computed correlation terms and the normalization term at a second downsampling rate; computing a pre-filtered gain control metric using a given function of at least the downsampled correlation terms; and filtering the pre-filtered gain control metric to generate the gain control metric.