Evaluation of Improved Classification of Speech-Like Waveforms Used for Secure Voice Transmission

Abstract

This paper evaluates speech-like (SL) waveform based secure voice transmission over various voice communication channels. In light of the fact that different voice channels exhibit different problems during transmission in terms of non-linearity, signal compression, etc. and call quality is heavily dependent on the type of communication equipment, conventional SL waveform based codebook (CB) as a unique solution was deemed insufficient for reliable secure communication. Principal improvement is in introduction of more sophisticated symbol classification and recognition technique that led to a significant error reduction, rendering this secure transmission method applicable in multiple voice communication scenarios. Simulations that were carried out in real-time scenarios with genuine equipment confirmed the supremacy of the proposed modification over the conventional solution.