The Qos Of The Network Audio Transmission System Research

The rapid development of the Internet breeds various novel applications on Internet improving each aspect of our life. All kinds of multimedia applications based on the Internet enrich the way people acquire information due to the broaden of Internet bandwidth. Among all multimedia applications, audio applications is a fully developed branch which is quietly replacing our traditional life style. For instance, the Internet radio is gradually replacing FM radio; the low-costing low-charging IP phone has a trend to replace traditional dial phone system; listening songs on the Internet is becoming more and more popular.However, with all the Internet based application put into use, the throughput booms rapidly which directly affects the QoS of Internet audio applications who require guaranteed bandwidth. In order to ensure the QoS of audio applications, solutions have been proposed from two different aspects. One solution is to improve the routers in the Internet which support certain QoS strategy so that the QoS of audio (and any other multimedia) applications is guaranteed. The other solution is to implement rate control mechanism in audio application system which controls the sending rate of audio application to match the real-time network status guaranteeing the audio stream QoS. Since it takes a long time and great cost to update all the routers in the Internet, the first solution is not as simple to implement and widely used as the second one.In this paper, we studied and did great research on the existing network audio application and reached the following conclusion. That's all the network audio application has a delicate downward strategy on rate adjustment and a rough upward strategy on rate adjustment which causes unnecessary packet loss and audio fluctuation and deteriorate the QoS.To solve the above problem, a novel rate control algorithm called Available Bandwidth Based Rate Control (ABBR for short) is proposed. ABBR adjusts the audio sending rate according to the newly real-time measured available bandwidth. So that when ABBR needs to increase audio sending rate, it can offer a more reasonable rate considering the measured available bandwidth which reduces or prevents congestion, packet loss and audio fluctuation etc. and increases the audio QoS. Simulations are done to demonstrate the advantage of ABBR against some mainstream algorithms in terms of QoS.In the last, we implemented the ABBR system and related some important details in the implementation.