Performance Analysis of Voice over WLAN Intercom System and Optimized Implementation for Android Users

摘要

The recent popularity of Wi-Fi and Voice over IP (VoIP) has occurred in part because converged voice/data network projects are arduous and tricky to implement. The continuously increasing expenses for baseband communication demand cheaper and reliable alternatives for voice and text data communication. Wireless LAN certainly isn't the most efficient infrastructure enhancement for Intercom systems but 802.11 has evinced to be working satisfactorily for most VoIP telephony. Besides, the shift from Wired to Wireless IP phones has been a major breakthrough proving to be profitable and convenient for users due to increased mobility. Voice over Wireless LAN (VoWLAN) depends on various elements like the hardware, network traffic, codecs used and digital modulation techniques that leads to variations in latency and packet delay. This paper discusses and compares the simulation results of VoWLAN for a confined area (a wireless intercom system) using different hybrid codecs like G.711, G.729 and G.723 and modulation techniques for getting an optimized result using OPNET modeler. The Quality of Service (QoS) is discussed for different network architectures that include communication via wireless router and Wi-Fi Peer to Peer communication using SIP routing protocol. By studying the QoS parameters, an optimized solution is proposed to eliminate the use of a centralized server, solve the varying IP address mapping issue. Appropriate digital modulation techniques and cryptographic encryption algorithms were used for security enhancement, thus preventing SYN Flood Attacks and eavesdropping.