Anti-Jamming Performance of Chaos-Based Digital Communication Systems Under Wideband Pulsed-Noise Jammers

In this chapter we continue our study of the anti-jamming capability of chaos-based digital communication systems. In particular, we attempt to analyze the performance of chaos-based digital communication systems under the influence of a pulsed-noise jammer, which turns on and off periodically producing a wideband jamming source [Peterson et al. (1995)]. The philosophy of the pulsed-noise jammer is to concentrate the jamming power during the “on” time to severely disrupt the spread-spectrum communication system. The duty factor, p, is the fraction of time during which the jammer turns on. Two types of pulsed-noise jammers are considered, namely, slowly switching and fast switching jammers. For the slowly switching jammer, the frequency at which the jamming signal switches between “on” and “off” is much lower than the bit frequency of the information signal. For the fast switching jammer, the switching frequency is assumed to be very close to the bit frequency. Within each bit period, therefore, the jammer is assumed to be turned on for a fraction p of the symbol period and is off for the remaining symbol period. The objective of our study is to determine the factors and the extent to which these factors would affect the performance of chaos-based systems. Analytical bit error rates (BERs) are derived, allowing the evaluation of performance for a range of noise level, jamming power, spreading factor and duty factor. For the case of slowly switching jammers, the value of p that maximizes the BER is also found analytically.