A system and method for channel estimation and echo cancellation in wireless system repeaters. A repeater with improved echo cancellation comprises an input radio control element having a receiving antenna and an output radio control element having a transmitting antenna; a power amplifier connected between the input radio control element and the output radio control element; and a signal processing unit connected between the input radio control element and the output radio control element. The signal processing unit is configured to estimate the communication channel from the transmitting antenna to the receiving antenna to produce a channel estimation. The signal processing unit is further configured to perform echo cancellation based on the channel estimation.