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A Study on Preservation and Recovery Mechanisms of Temporal Structure of Continuous Media in Mobile Multimedia Communications

移动多媒体通信中连续媒体时间结构的保存与恢复机制研究

基本信息

批准号：
12555109
负责人：
TASAKA Shuji
金额：
$ 8.26万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

The research results can be classified into the following four categories.1. We have studied the media synchronization quality for stored audio-video transmission in a wireless LAN environment with handover. By experiment, we have demonstrated that a retransmission-based error recovery scheme RVTR with dynamic resolution control of video can improve the voice quality.2. We have proposed a traffic control scheme for continuous media over a PHS 64kbps best-effort channel, whose transmission capacity changes between two values according to network conditions. We developed two types of experimental systems : one changes the capacity only within a base station, and the other switches it by handover between two public base stations. The experiment showed the effectiveness of the scheme.3. Experimental assessment of the media synchronization quality in a Bluetooth LAN access system has been made when a server transfers stored audio and video streams to a terminal with point-to-point communication. We first examined the effects of the interference from DSSS wireless LAN systems and Bluetooth packet types on the quality. We then studied the effect of segmentation mismatch caused by the difference between the RFCOMM Maximum Frame Size and the baseband packet payload size. We also proposed a scheme that adaptively selects the best packet type according to the network condition and showed its effectiveness by experiment.4. An experimental study on inter-destination synchronization control has been done in an integrated wired and wireless network that consists of a router-based IP network and a wireless LAN with two base stations. A server in the wired network multicasts a pair of audio and video streams to a wired terminal and a wireless terminal which performs handover from one base station to the other. We measured the synchronization quality of inter-destination as well as intra-stream and inter-stream.

研究成果可以归纳为以下四类：1.我们研究了在无线局域网环境中切换存储的音频视频传输的媒体同步质量。通过实验证明了基于重传的差错恢复方案RVTR和视频的动态分辨率控制可以提高语音质量.我们提出了一种PHS 64 kbps尽力而为信道上连续媒体的流量控制方案，该信道的传输容量根据网络条件在两个值之间变化。我们开发了两种类型的实验系统：一个只在基站内改变容量，另一个通过两个公共基站之间的切换来切换容量。实验证明了该方案的有效性.在蓝牙局域网接入系统的媒体同步质量的实验评估已经作出了当服务器传输存储的音频和视频流到终端与点对点通信。我们首先研究了DSSS无线局域网系统和蓝牙数据包类型的干扰对质量的影响。然后，我们研究了RFCOMM最大帧大小和基带数据包有效载荷大小之间的差异引起的分段不匹配的影响。提出了一种根据网络状况自适应选择最佳分组类型的方案，并通过实验验证了其有效性.在由基于路由器的IP网络和具有两个基站的无线局域网组成的有线和无线综合网络中，对目的地间同步控制进行了实验研究。有线网络中的服务器向有线终端和无线终端多播一对音频和视频流，无线终端执行从一个基站到另一个基站的切换。我们测量了目的地之间以及流内和流间的同步质量。