Research on Wireless Internetworking and Application Support

我们的工作目标是建立一个能够用各种无线接入技术透明地支持移动应用的网络平台。(1)无线互联技术的开发与实现针对无线互联技术，提出了公平调度算法。详细设计并实现了无线局域网的信道分配算法和最小带宽保证调度算法。在Linux操作系统上进行了实验床实现，并对高密度网络架构进行了研究。在高密度网络中，我们假设有大量的联网设备。为了实现这种网络体系结构，必须处理节点的异构性。对此，我们提出了稳定性自适应路由和多对一通信协议。在ns-2(网络模拟器2)上对这些协议进行了仿真。(2)应用支撑服务的开发和测试床网络的制作开发了高速无线网络中的按需数据预取系统。在如此高速的网络中，由于不连续的小小区，移动设备只能停留很短的时间。该方法利用另一个接入网络进行数据请求，利用高速网络进行数据下载，构建了移动主机具有PHS和WaveLAN两种网络接口的实验网络，实验结果表明，该预取方法即使在主干网络发生拥塞的情况下也能保持较高的吞吐量。

The goal of our work is to establish a networking platform in which mobile applications can be supported transparently with various wireless access technologies.(1) Development and Implementation of Wireless Internetworking TechnologyAs for wireless internetworking technology, fair scheduling algorithms were developed. In detail, Channel assignment algorithms for wireless LAN, and minimum bandwidth guaranteed scheduler were designed and implemented. We made testbed implementation by using Linux operating system.High density network architecture was also studied. In high density network, we assume tremendous number of networked devices. The nodes heterogeneity must be handled for achieving this network architecture. Toward this, we proposed stability adaptive routing and many-to-one communication protocol. These protocols were simulated by ns-2 (network simulator 2).(2) Development of Application Support Service and Making of Testbed NetworksOn-demand data prefetching system in high-speed wireless networks was developed. In such high speed networks, mobiles can stay for only short time due to the discontinuous small cells. Our method utilizes another access network for data request and high-speed network for data downloading.We made tastbed networks in which mobile hosts have two network interfaces, PHS and WaveLAN.Experimental results show our prefetching method can keep high throughput even when congestion occurs in backbone networks.