Effect of Worst-Case Multiple Jammers on Coded FH/SSMA Systems

摘要

This report characterizes and evaluates the effect of simultaneous multiplepartial-band noise or tone jammers and other-user interference on a single communication link employing frequency-hopped spread-spectrum (FH/SS) signaling, M-ary frequency-shift-keying (FSK) modulation with noncoherent demodulation, and Reed-Solomon coding. For the symbol error probability of these systems, we derive exact expressions in the absence of multiple-access (MA) interference and tight upper bounds in the presence of other-user interference. Although our analytical methods are valid for any number of multiple jammers, we restrict our numerical study to the cases of two and three partial-band noise and tone jammers. For fixed values of the spectral densities of noise jammers, or the energies per symbol of tone jammers, we evaluate the worst-case fraction of the band that each jammer should use in order to maximize the error probability of the FH/SS or FH/SSMA system. For the range of the signal-to-jammer power ratios examined, multiple noise or tone jammers appear to have no advantage over a single noise or tone jammer of equivalent spectral density or energy per symbol but achieve approximately the same worst-case performance by jamming smaller fractions of the band. Keywords: Jamming, Antijamming, Frequency hopping, Frequency shift keying, Spread spectrum, Multiuser interference, Multiple access, Error correction codes. (jhd)