Turbo codes for coherent FH-SS with partial band interference

Abstract

In this paper, turbo codes are investigated in a slow frequency-hopped spread spectrum (FH-SS) system with partial-band jamming. In addition, full-band thermal noise is present. This paper focuses on the implementation of a modified turbo decoder for this model. We consider cases of known or unknown channel state and variable number of bits per hop. Our approach is to modify the calculation of branch transition probabilities inherent in the decoder. Analytical bounds are derived and simulation is performed for coherent demodulation. The results drawn from this code are compared with a convolutional code.