On the application of chirp modulation in spread spectrum communication systems

Abstract

The paper presents a novel method of enhancing the interference immunity of a direct sequence spread spectrum system. The method is based on applying a chirp signal to modulate the spreaded sequence. At the receiver we apply a time varying filter to recover the transmitted signal. This scheme is well suited for handling stationary as well as non-stationary interference. In addition, our method improves with respect to the conventional system the receiver performance even when the interference is not present. An analytic expression of the receiver SNR is derived. Simulation results show the improvement in terms of the bit error rate of the proposed technique, with respect to the conventional direct sequence spread spectrum.