A method for estimating interference between a plurality of carrier signals in a multi-channel system including injecting pilot symbols into a first carrier signal and transmitting the first carrier signal, transmitting a second carrier signal, receiving at least the first carrier signal and the second carrier signal, and estimating interference between the received first carrier signal and the received second carrier signal based, at least in part, on measuring the received first carrier signal when a pilot symbol of the first carrier signal is received. A multi-channel communication system including a plurality of transmitters for a plurality of carrier signals, a pilot symbol injector for injecting silent pilot symbols into at least one of the carrier signals, a plurality of receivers for the plurality of carrier signals, and an interference estimator configured to estimate interference between at least two of the plurality of carrier signals based, at least in part, on receiving silent pilot symbols in at least one of the at least two of the plurality of carrier signals. Related apparatus and methods are also described.