Design And Implementation Of Multimedia Broadcasting For Intellegent Mobile Terminals And Performance Optimization

With the constant development of wireless transmission technologies, multimedia technologies and mobile devices, it becomes more and more important to provide multimedia streams to mobile devices.However, due to the limitation of the bandwidth of wireless networks and the capability of mobile devices, multimedia service has not been widely used for mobile devices.A MTG system has been designed and developed in this thesis, which can provide multimedia broadcasting service to intelligent mobile terminals in WLAN.How to provide appropriate multimedia streams to mobile devices, and to ensure the multimedia streams be displayed smoothly and fluently in mobile devices are the focus of the work in this thesis.The proposed MTG (Multimedia Transcoding Gateway) system can provide appropriate multimedia streams to mobile devices.It transcodes the multimedia streams encoded in MPEG2-TS,which is used in the mobile broadcasting TV and not suitable for receiving by mobile devices, to MPEG4, which is more suitable for transmission in WLAN and receiving by mobile devices.Test results show that the implemented MTG system works well for intelligent mobile devices (Nokia N800).Moreover, because of the unreliability of wireless transmissions,and the no feedback features of broadcasting, the packet loss rate is very high, which somewhat affects the user's experience for using the multimedia service. To solve this problem, we provide a new Radio Optimization Scheme based on three-layer architecture. The simulation results show that the performance of the multimedia transmission using the proposed scheme becomes much better than using the original mechanism. The packet loss rate decreases a lot and the throughput of the data increases.