A method of generating a noisy receive signal for testing the performance of a mobile wireless communication device is described. A signal generator unit generates a transmit signal that frequency hops among a set of carrier frequency channels in a cyclic pattern having a time duration T. A wireless channel emulator unit generates a receive signal by modifying the transmit signal and also generates an interference signal by modifying the receive signal. The wireless channel emulator unit delays the interference signal relative to the receive signal by an integer multiple of the time duration T. The receive signal and the interference signal are combined by a combiner unit to generate the noisy receive signal.