Analysis of frequency-hopping systems with combined convolutional and diversity encoding and non-ideal interleaving in worst case partial band jamming

Abstract

ABslwcrThe interleaving span of coded Frequency-Hopping (FH) systems is often constrained to be smaller than the decoder memory length, i.e., non ideal interleaving is performed. An upper bound on the performance of a Viterbi decoder of a convolutional code with non ideal interleaving is presented. Also, a soft decision diversity combining technique is introduced and the performance of combined convolutional and diversity coding subject to worst case partial band noise jamming is investigated. The considered FH system employs M-ary Frequency Shift Keying (MFSK) modulation and noncoherent demodulation with 2 bit soft decision based on Viterbi's ratio-threshold technique.