Performance Analysis of VoIP using Different Voice Encoding Schemes

Transmission of voice over Internet is one of the fastest growing applications in last decade. It is a viable alternative to the traditional telephony systems due to its high resource utilization and cost efficiency. VoIP has evolved from a meagre protocol to become the backbone of the next generation communication networks. Meanwhile, Wireless Local Area Network (WLAN) has become a ubiquitous networking technology getting deployed throughout the world. Driven by these two popular technologies, Voice over WLAN has been emerging as a powerful infrastructure to provide low-cost wireless voice services. The objective of this research paper is to evaluate the network QoS parameters while using various coding schemes for Voice over IP (VoIP) over 802.11b WLAN in a simulated campus network environment. We evaluated and observed the performance of the various metrics like throughput and packet end-to-end delay for VoIP in a Wi-Fi simulation environment executed on OPNET simulator, where different scenarios were created for finding optimal parameters. Results obtained by simulating these metrics for different encoding schemes (G.711, G.726, G.729, and G.723) for all three multiple access technologies viz. Direct Sequence, Frequency Hopping and Infrared. Certain inferences have been made to suggest the best coding scheme for future data communication applications.