Multimedia Transmission System on FDDI

最近，各种类型的超高速局域网被提出。其中，FDDI(光纤分布式数据接口)是最有前途的一种。目前，它主要用作数据终端的主干局域网。然而，由于它的速度足以提供多媒体通信，因此具有用作多媒体局域网的潜力。从这一角度出发，我们新开发了流量控制算法来控制多媒体信号的流量，特别是运动图像和语音的流量。我们还研究了与上述流量控制相匹配的图像编码技术。首先，我们研究了使用FDDI的异步类的恒速率运动图像传输，并检查了业务量与定义传输优先级的阈值之间的关系。然后，我们确定了能够处理这种实时通信的网络配置，即站点的数量，并讨论了使用异步类进行变比特率图像传输的方法。因此，我们提出了一种新的算法，即使在总业务量很大的情况下，也能保证高优先级图像信号的传输，其中高优先级图像信号通常对应于低频信号。对于图像编码，我们研究了子带编码，因为它非常适合优先级控制。例如，我们提出了各种类型的超短型滤光片。我们还构造了M个通道滤波器组，其中M不是2的幂。

Recently, various types of very high-speed Local Area Networks have been proposed. Among them, FDDI (Fiber Distributed Data Interface) is the most promising one. At present, it is mainly used as back-bone LAN of Data Terminals. It has, however, the potential to be used as Multimedia LAN since its speed is enough affording the multimedia communication. From this point of view, we newly developed flow control algorithm to control the flow of multimedia signals, especially moving images and voices. We also studied the image coding technique matched with the above flow control.First, we studied the constant rate moving image transimission using the asynchronous class of FDDI.We examined the relationship between the traffic and the threshold valuewhich defines the priority level of transmission. Then, we fined the network configuration, namely the number of stations, which can handle such a real time communication.We also discussed the variable bit rate image transmission using the asynchrouns class. As a result we proposed a new algorithm in which the transmission of high priority image signals, which generally correspond to the low frequency signals, is guranteed even if the total traffic is very high.For the image coding, we studid the sub-band coding, since it suits the priority control very well. For exmaple, we proposed various types of very short type filters. We also composed M channel filter banks in which M is not a power of two.