Performance of M-ary FH-DPSK systems in the presence of jamming

It is shown that the antijamming (AJ) performance of binary FH-DPSK systems is, for all practical purposes, equivalent to (4-ary) FH-DQPSK and that an 8-ary FH-DPSK system has approximately 1.5-dB worse performance relative to binary FH-DPSK. In addition, it is shown that an optimized partial-band multitone jammer (PBMJ) and a partial-band noise jammer (PBNJ) yield essentially equivalent AJ performance in the absence of thermal noise. The present results diverge from those of M.K. Simon et al. (1982, 1985) who concluded that the PBMTJ is 4.4 dB more effective than PBNJ. It is concluded that the differences between the present results and those of Simon et al. are attributable to the fact that they did not use the entropy of a frequency-hopping carrier as a design parameter to be optimized.<>