Modulated (Soft-Decision) Differential Frequency Hopping System

A novel FH system named modulated differential frequency hopping (ab. MDFH) system was proposed. In MDFH system, some information was used to produce pseudo-randomly carrier frequency slot (which was just like DFH technology), others was changed into narrowband modulated waveforms (which was just like conventional FH technology). The transmitted signal (narrowband modulated waveform) occupied one or more of the available frequency slots, then the MDFH system came into being. The theoretic analysis and the simulation results showed that, compared to the DFH system, the information rate of the MDFH system was increased. And compared to the conventional FH system, not only the information rate of MDFH system was increased obviously but also the performance of the average bit error rate (BER) in AWGN channel was improved with soft-decision Trellis decoding.