Ad Hoc 網路上以分時方式之媒體存取控制具有可靠性及適應性之通訊協定

Abstract

Abstract In mobile ad hoc networks, many broadcast algorithms have been proposed for mobile ad-hoc networks. Almost all existing algorithms assume the partial/entire network topology information is knows. It requires heavy maintenance costs when the network topology changes quickly and frequently. In this dissertation, we propose a new mobility-transparent deterministic broadcast algorithm for ad-hoc networks. Reliable broadcast at the MAC layer is very important to support higher layer protocols like routing protocols at the network layer. If the underlying MAC protocol can ensure reliable broadcast, network layer broadcast and multicast can benefit a great deal in terms of channel utilization. Some wireless MAC protocols such as IEEE 802.11 were not designed to capitalize in an efficient manner. Many schemes have been proposed to solve this problem. In these schemes, the network performance will degrade quickly as the number of mobile hosts increases due to high contention collision. We present a reliable broadcast and adaptive (RAMAC) medium access control protocol with GPS support. This scheme can solve the deadlock problem and the scalable problem. Besides, if we want to design an efficient multi-channel MAC, the bandwidth usage rate should be considered. RAMAC can be easily extended to the multi-channel MAC protocol (M-RAMAC) for wireless networks. In M-RAMAC, the bandwidth usage rate is high in each sub-channel.