Using complementary sequences for direct transmission path identification

RADAR and SONAR, as well as communication systems transmit a signal that travels along a transmission path, reflecting on the surrounding obstacles during the transmission-reception process. The transmission channel behaves as a linear filter with an impulse response characterized by h[n] or its frequency counterpart H(ω). In such applications it is mandatory to identify the impulse response of the transmission path in order to extract time, frequency, and physical environment information (RADAR/SONAR) or to reduce the distortion effects by means of channel equalization in communication systems. Furthermore, in additive white Gaussian noise (AWGN) channels, the receiver noise reduces the accuracy of the estimation. This work presents a direct, noniterative technique for system identification by using complementary sequences in order to increase the estimation accuracy.