Optimal interceptor for frequency-hopped DPSK waveform

In this paper we study the optimal interceptor for a frequency-hopped binary differential phase shift keying (FH-DPSK) waveform. We derive the detection algorithm based on the maximum likelihood principle. The likelihood ratios of all signal levels-the chip (symbol), hop, frame, and message level are thoroughly derived. The complete block diagram of the optimal interceptor is presented. We show an approximation of the optimal interceptor, illustrating the underlying operation principles. Furthermore, we propose a novel performance evaluation approach and illustrate it through numerical examples. The optimal interceptor and the well-known filler-bank combiner (FBC) interceptor are compared in performance. Under the considered detection quality requirements and the transmission modes, the gain ranges from 1 to 7 dB.