An analytical study of the performance of fast frequency-hopped (FFH), M-ary orthogonal frequency-shift keyed noncoherent modulation with linear combining of square-law envelopes in the presence of multitone interference is presented. The multiple equal-power interference tones are assumed to correspond to some of the possible FFH/M-ary orthogonal signaling tones. It is also assumed that the channel fading characteristics of the signal and interference tones are independent. We evaluate the effect of the channel fading on the system's performance as a function of various parameters, such as the number of hops per symbol, the signal power to multitone interference power ratio, and the number of interference tones. Our numerical results indicate that by use of square-law time diversity combining, a large number of hops per symbol make the bit-error probability of the system more sensitive to the fading of multitone interference. Finally, the analysis has been proven valid by simulation.

The effects of channel fading of multitone interference on the performance of multiple hops per symbol fast frequency-hopped (FFH), M-ary orthogonal frequency-shift keyed (MFSK) noncoherent systems are analytically investigated. The multiple equal-power interference tones are assumed to correspond to some of the possible FFH/M-ary orthogonal signaling tones. It is also assumed that the channel fading characteristics are independent for the signal tone and interference tone. We evaluate how the effect of the multitone interference fading on system performance is changed by various parameters, such as the number of interference tones, the number of hops per symbol and the modulation order. In addition, our numerical results indicate that the larger number of hops per symbol makes the system performance more sensitive to the fading of multitone interference.