Usign OPNET and MATLAB for Assesing Voice Codecs Impact on NGN/VoIP Applications

Abstract

Nowadays, telecommunications operators tend to move towards a new implementation of Voice over Internet Protocol in public networks. IP networks are not designed to bear real time applications and some parameters such as network delay, delay variation and packet loss are responsible for the voice quality perceived by the user. The main challenge of these networks is how to measure and predict voice quality in an accurate and efficient way, in order to control and monitor that the Quality of Service complies with technical and market requirements. This paper models the behaviour of a VoIP network and simulates some communication scenarios to test the impact of transmission parameters decline, from a qualitative viewpoint, through the simulation tool OPNET IT GURU. The possibility of complementing the simulation study by using MATLAB is also analyzed.