Quality Of Service In UMTS Network And Improvement VOIP Performance

This study adopted a simulation based network performance analysis to investigate the effects of the application of different voice encoder schemes on QoS of VoIP system ,deployed with UMTS network Through different network simulation experiments using realistic network scenarios in OPNET environment, the results indicated that the choice of suitable voice encoder scheme with a small number of voice frame size per packet have a significant impact over VoIP traffic performance when deployed with UMTS access technology the VoIP over UMTS network model has been developed, where a VoIP server development is connected in the UMTS model the QoS factors will be controlled and managed to ensure good quality in VoIP call , the design of layered coding and multiple description coding is employed to address the bandwidth f luctuations and packet loss problems in the wireless network and to further enhance the error resilience, this research provided an in depth network performance comparative analysis of VoIP over UMTS using performance parameters which indicate QoS such as end to end packet loss ,throughput ,end to end delay ,uplink traffic sent ,uplink traffic received voice ,downlink traffic sent ,downlink traffic received, voice packet delay, average in voice packet end to end delay by using the GSM ,G729A CODEC in frames (20, 30 ms). The obtained simulation experiment results indicated that choice of suitable codec scheme can affect the QoS of VoIP traffic over UMTS network.