Capacity and cutoff rate of coded FH/MFSK communications with imperfect side information generators

摘要

When JSI (jamming state information) is imperfect due to thermal noise, the capacities and cutoff rates of the channels are calculated as a function of the signal-to-jamming-noise ratio for memoryless, noncoherent FH/MFSK (frequency-hopped M-ary frequency-shift-keying) systems under partial-band noise jamming (PBNJ). Both soft- and hard-decision metrics with perfect, imperfect, and no JSI are considered. The first of three imperfect JSI generator uses the maximum a posteriori (MAP) decision rule based on the energy from an FH tone frequency which is near the M-signaling FH tone frequencies. The second decision rule utilizes the MAP rule, but it is based on the total energy received at the M-signaling FH tone frequencies. The third generator has the same decision statistics as the second generator, but its decision rule is an easily implementable suboptimum rule. If hard decision are made and code rates are high, then the differences between the imperfect JSI generators and perfect JSI generator can be larger than 1 dB. If soft decisions are made, then the differences between the imperfect and perfect JSI cases are negligible.