Comparison of signal quality of present and alternative maritime VHF communication systems

This paper presents an analysis, based on the simulation model, of the existing broadband and alternative narrowband maritime very high frequency (VHF) radiotelephone communication systems. The alternative system proposed by the International Telecommunication Union (ITU) organization is one of the possible solutions to the lack of communication channels in the maritime VHF bands. The influence of changes in the modulation process on the quality of information in the maritime VHF radiotelephone communications is examined using a computer simulation model taking into account all the relevant technical characteristics of maritime VHF radiotelephone equipment. The process of evaluating the quality of speech signals was carried out by means of an objective quality assessment technology using a computer program that implements perceptual evaluation of speed quality (PESQ) algorithm which ensures the comparability of obtained results with the traditional method of subjective evaluation of signal quality. The process of quality assessment was conducted using four standardized sample voice signals with different influences of external interference on the communication channel. Analysis of the results confirms the possibility of using alternative communication systems.