Dynamic Network Control to Prevent System Failures in Multi-hop Wireless Networks

在多跳无线网络中，网络不能保证连接，由于节点的位置经常变化，网络的拓扑结构会随着时间的推移而变化，一些节点会因为节点的移动而离开网络。由于这种拓扑结构的变化，有时会降低网络的性能。此外，如果网络由一般终端组成，则可能会有恶意节点进入网络，对网络进行故意攻击。因此，网络可能无法正常运行。由于最近的网络系统必须提供足够的可靠性和宽带环境，我们必须克服这些导致系统故障的问题。在此背景下，本课题的目的是研究网络控制方法来克服这些问题，提高多跳无线网络的可靠性。研究结果如下：研究了计算机病毒导致的终端故障对无线多跳网络性能的影响，并提出了一些防止病毒在网络中传播的方法。此外，我们还提出了采用中继站的拓扑控制方法来提高可靠性，并对所提出的方法进行了评估。此外，我们还提出了用于负载平衡的收费奖励方法，并对所提出的方法进行了评估。此外，我们还开发和评估了一些优化方法和协议，以提高可靠性。

In multi-hop wireless networks, the network is not guaranteed to be connected, and the topology of the network changes with time because positions of nodes often change and some nodes leave the network because of mobility of nodes. Due to such change of the topology, performance of the network is sometimes degraded. Furthermore, if the network consists of general terminals, malicious nodes may enter the network and attack the network intentionally. As a result, the network may fail to function properly. Because recent network systems have to provide sufficient reliability as well as broadband environments, we have to overcome such problems which cause system failures. With these things as background, the purpose of this project is to develop network control methods to overcome such problems and improve reliability of multi-hop wireless networks. The following are the results: We showed that effects of failure of terminals due to computer viruses on performance of wireless multi-hop networks, and proposed some methods to prevent spread of viruses in the network. Also, we proposed topology control methods with relaying stations to improve reliability, and evaluated the proposed methods. Also, we proposed charging rewarding methods for load balancing and evaluated the proposed methods. Furthermore, we developed and evaluated some optimization methods and protocols to improve reliability.