Research Of Channel Resource Assignment In Wireless Mesh Networks

Wireless mesh networks can provide"last mile"broadband wireless access, so it is a promising technology in next generation wireless networks. However, the effectiveness of channel resource assignment is critical to improve the network capacity of wireless mesh networks.First of all, the primilary knowledge of wireless network and channel assignment are introduced. The architecture, characteristics and key issues of wireless mesh networks, as well as multi-radio multi-channel technique are disscussed. Moreover, channel assignment problem, including the property of channel assignment in cellular networks, ad hoc networks and wireless mesh networks are studied. The primary focus is on the summary of channel assignment models, strategies and key problems.Second, based on the 863 project, the channel resource assignment problem of virtual hierarchical wireless mesh networks is addressed in the theoretic and practical point of view. The architecture of virtual hierarchical wireless mesh networks is analyzed, involving network topology, networking strength and challenge. The principle and model of channel assignment are researched according to the particularity of the network.Then, the capacity of channel assignment in virtual hierarchical wireless mesh networks is mainly analyzed. The impact on network capacity while using the general channel resource, including radio interface, frequency spectrum, time and space, is investigated. Numerical results suggest that the use of general channel resource in virtual hierarchical wireless mesh networks can improve network capacity dramatically, on the basis of which the channel assignment strategy combining the time and space is presented.Furthermore, the channel assignment algorithm in virtual hierarchical wireless mesh networks is studied. Aiming to solve the channel assignment in virtual cells, an algorithm is proposed by means of dividing network into cell groups and reusing channel resource in space. The size of the cell group is computed by studying the communication and the interference range while communicating within the cell and adopting SINR as an interference index. An algorithm combining of graph model and SINR calculation is also proposed to solving the channel assignment for communication between virtual cells. Similaring to the decomposition of graph in matroid theory, the network is decomposed into subsets which is colored sequently while using SINR to avoid interference. The algorithm analysis and simulation results show that the proposed channel assignment algorithm is capable of achieving network throughput with low computational complexity while avoiding network interference, which is easy to adapt to the communication demand and easy to realize in realistic environment.Finally, a technical case of channel assignment in virtual hierarchical wireless mesh networks is described, which demonstrated the proposed channel assignment algorithm in the process of operation practically.