Design And Implementation Of The Gateway System Supporting New Multimedia Services Under The Wireless Environment

Currently, with the development of technologies, the traditional information and media services cannot meet people's need gradually. Information provisioning is changing from fixed to mobile, from speech and voice to image and multimedia. People are now becoming more and more willing to get the multimedia information they want at any time and anywhere using their mobile devices. And there are more and more demands for providing multimedia services through mobile wireless devices.Based on the analyse of several main wireless and mobile multimedia service provisioning technologies, this thesis proposes a new solution for providing mobile multimedia services. The solution makes full use of the advantages of DVB-T and WLAN technology from the viewpoint of multimedia service provisioning, and combines the two networks together. Moreover, a gateway system supporting multimedia services under wireless environment has been designed and implemented. The gateway system can receive the real-time TV programs from DVB-T network and forward them to users in WLAN network. It realizes the functions of transcoding and bitstream rate controlling. Besides, the gateway system can also provide various information services, such as EPG (Electronic Program Guide), weather forecast, announcement etc.Regarding the design and implementation of the gateway system, the thesis focuses on how to solve the data incompatibility problem brought by the difference of DVB-T and WLAN network. By using transcoding, streaming and multiprocessing technologies, the gateway system can supply different kinds of multimedia streams to mobile devices according to the network bandwidth and the processing capabilities of the mobile devices. Various experiments are also made to test and improve the implemented gateway system, e.g., using different media codec formats, screen sizes as well as transmission rates etc.In addition, to test the gateway system, the thesis discusses also how to improve the media player in the wireless handset (Nokia N800) so that it can receive the bitstream data through both unicasting and broadcasting.