| As the increasing expectations for communication, "Ubiquitous", "Broadband" and "Wireless" have become the three most popular and important words in Telecommunication. In this situation, wireless mesh networks (WMNs), as a promising technology to meet the target, are attracting more and more attention from both industry and academia.However, for a WMN to achieve the expectations, considerable research efforts are still needed. There are open issues in physical layer, medium access control (MAC) layer, routing layer, transport layer and application layer. This thesis focuses on the algorithms and protocols of MAC layer, routing layer and intrusion detection in WMNs. Based on the state of the arts in-depth studies, I have done the following innovative works:1. Proposed a fast forward MAC (FFMAC) protocol for IEEE 802.11s based multi-hop multi-channel WMNs. Most of the current MAC protocols have been designed only for one-hop communication and they are not suitable for multi-hop WMNs, especially not suitable for multi-hop WMNs with real-time applications. Therefore, the FFMAC is proposed for quality of service (QoS) guarantee in multi-hop multi-channel WMNs. By providing higher priority for real-time applications, FFMAC reduces the end-to-end delay and increases throughput significantly.2. Proposed a future channel reservation MAC (FCR-MAC) for multi-radio multi-channel WMNs. To mitigate the "deafness" and the "multi-hop hidden terminal" problems, a feasible solution is to equip each node with a control radio and fix it on a common control channel (CCC). However, the application of the CCC introduces other problems. Depending on the number of available data channels, the CCC may be under-utilized or may become a bottleneck. To address these challenges, a novel MAC protocol based on future channel reservation is proposed in this thesis. The proposed FCR-MAC guarantees higher utilization of channel resources and reduces the average delay in performing channel negotiation and reservation.3. Proposed a spectrum-tree based on-demand routing protocol (STOD-RP) for cognitive wireless mesh networks. Although WMN is regarded as the key technology for next-generation wireless networks, its performance is limited by the crowded unlicensed band. Meanwhile, cognitive radio (CR), with its capability to support flexible usage of wireless radio spectrum, can let unlicensed users to access licensed band opportunistically. Hence, I used the CR capability to complement the WMN and proposed a spectrum-tree based on-demand routing protocol. The STOD-RP addresses the cooperation between spectrum decision and route selection in an efficient way. In addition, a new route metric is proposed as well as a spectrum-adaptive route recovery method.4. Proposed a spectrum- and energy-aware routing protocol (SEA-RP) for cognitive wireless mesh networks. Energy is a crucial factor for client WMNs because many devices are powered by batteries with a limited lifetime. By combining the on-demand spectrum sensing mode with an energy-save route discovery scheme, the proposed SEA-RP addresses the cooperation between spectrum decision and route selection in an efficient way and eliminates unnecessary energy consumption.5. Proposed a convex quadratic optimization approach for distributed intrusion detection in WMNs. Due to the lack of a centralized infrastructure, the distributed intrusion detection is necessary for protecting WMNs. A generic problem in distributed intrusion detection is to integrate a variety of local detection information from multiple dispersed nodes effectively. Therefore, a convex quadratic optimization approach is proposed to integrate the dispersed local detected information. The proposed approach can considerably reduces incorrect judgment and has low complexity. Moreover, an algorithm for node's trustworthiness and a feedback scheme is presented as well.
|
PDF Full Text Request