A Study on Transport/Routing Protocols on Ad Hoc Networks for High-Speed Data Service

An ad hoc network is a distributed and self-organized network, where wireless terminals exchange network information with neighbor terminals and construct a multi-hop network. The topology of such a network changes frequently because of the unsettled wireless environment and/or terminal mobility. Consequently, appropriate route maintenance is necessary. In this thesis, we first focus on a commercially available ad hoc wireless network system, the Flexible Radio Network (FRN). This system uses a proprietary protocol that provides multiple-route management and hop-by-hop transmission acknowledgement. We discuss the system performance, which was evaluated through simulations regarding the data-link and routing protocol of the FRN to clarify the system’s basic properties, and then explain some FRN problems that degrade the system performance. After that, we describe techniques to improve the performance. These techniques are aimed at improving the system parameter setting adaptively or at remedying the problems statically. Through simulation results, we show how the techniques improve system performance. In the second part of this thesis, we investigate high-speed data communication services provided over ad hoc networks. Ad hoc networks are expected to be integrated with wired networks and many applications will operate over TCP/IP (Transmission Control Protocol/Internet Protocol), so many studies have been dedicated to improving the performance of TCP over ad hoc networks. However, most of these studies assumed a persistent TCP connection. This is clearly inadequate because many TCP connections are actually