| Recent advances in portable computing and wireless technologies are opening up exciting possibilities for the broad application of wireless mobile networking. Research on wireless ad hoc networks becomes a hot research direction all over the world. Mobile Ad hoc Networks (MANETs) are collections of wireless mobile nodes constructed dynamically without the use of any existing network infrastructure or centralized administration. Unlike cellar networks, each mobile node in MANETs acts a router and is responsible for forwarding messages for its neighbors. In MANETs, wireless nodes have limited energy and bandwidth and network topology may change frequently due to mobility of nodes, which make routing protocols for MANETs more challengous than those for wired networks. With an increasing demand for advanced multimedia applications on voice and video, QoS routing plays a more and more important role.In this dissertation, we investigate the issues of QoS unicast routing and QoS multicast routing in MANETs on the basis of discussing and analyzing the existing protocols for MANETs. In this dissertation, some novel protocols and algorithms are proposed to reduce system blocking rate for a QoS call. They are summarized as follows:1. An improved timeslot assignment method is proposed in the CDMA/TDMA channel model. It expands an existing timeslot assignment algorithm for single-path unicasting in MANETs to work for the multiple-path/tree routing schemes proposed in the dissertation.2. A new QoS multipath unicast routing protocol is proposed. Since the available bandwidth is very limited in ad hoc networks, a QoS request between two nodes will be blocked if there does not exist a path that can meet the QoS requirements, even though there is enough free bandwidth in the whole system. Three path selection strategies are proposed, namely, shortest path first (SPF), largest bandwidth first (LBF), and largest hop-bandwidth first (LHBF). The aggregate bandwidth of the multiple paths can meet the bandwidth requirement of the call and the delays of these paths are within the required bound of the call. The simulation results show that the proposed multiple paths routing scheme significantly reduces the system blocking rates in various network environments, especially when the network load is heavy.3. A new QoS multipath multicast routing protocol is proposed. Due to limited bandwidth of a wireless node, a QoS multicast call could often be blocked if there does not exist a single multicast tree that has the requested bandwidth, even though there is enough bandwidth in the system to support the call. Three multicast routing strategies are studied, SPT (shortest path tree) based multiple-paths (SPTM), least cost tree based multiple-paths (LCTM) and multiple least cost trees (MLCT). The final routing tree(s) can meet the user's QoS requirements such that the delay from the source to any destination node shall not exceed the required bound and the aggregate bandwidth of the paths or trees shall meet the bandwidth requirement of the call. The simulation results show that the new scheme improves the call success ratio and makes a better use of network resources.4. A new QoS multicast routing by using multiple trees is proposed. The aggregate bandwidth of the multiple trees can meet the bandwidth requirement of a call and the delay from the source to the farthest destination node in any tree shall not exceed a pre-specified bound. Two strategies of this multiple tree routing scheme are studied, multiple shortest path trees (MSPT), and multiple minimum spanning trees (MMST). The simulation results show that the new routing scheme significantly improves the request success rate and makes a better use of network resources.5. The proposed QoS multipath routing schemes are applied in the wireless sensor networks (WSNs) to guarantee enough bandwidth for real time data aggregation. The simulation results show the effiency of the application.
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