مرکز منطقه ای اطلاع رساني علوم و فناوري - A new wireless VoIP signaling device supporting SIP and H.323 protocols considering Silence Suppression

Abstract :

Nowadays, VoIP is a technology with a great demand and Wireless networks are increasingly deployed. Each of these has its own technology constraints; For VoIP, it is very important to take into consideration the need to provide a high quality service according to well-defined standard transmission (jitter, end to end delay, MOS and packet loss). However, wireless networks (IEEE 802.11) are based on radio which undergoes a number of technical constraints to achieve theoretical transmission rates, among these constraints include the number of users of the networks, the distance between the client and the access and the amount of data transmitted point. However, to optimize and adapt the transmission resources available, the technique of Silence Suppression or VAD (Voice Activity Detection) is a method that prevents sending packets in the case where one or all parties of a communication are not talking. In this term, a study is made by simulating wireless network in OPNET Modeler with a fairly large number of VoIP (15 users) whose signaling is handled via a new node that was created specifically to manage the signaling tasks under SIP and H.323 in order to minimize the number of nodes in the network and avoid the congestion. In this paper, two scenarios are compared; the first contains a number of VoIP users with SIP and H.323 signaling handled by the new created device, the second scenario is similar to the first except that the concept of Silence suppression is considered to optimize and improve the Quality of Service.