Channel assignment and security in multi-channel multi-radio wireless mesh networks

Wireless Mesh Networks (WMNs) are a special kind of ad hoc networks in which most of the nodes are static. Different from ad hoc networks, a mesh network introduces a hierarchy in the network architecture and provides broadband wireless Internet access to users. Recent studies have shown that nodes in a WMN are equipped with several radio interfaces for better performance. The aggregate capacity of WMNs can be significantly improved by providing each node with several Wireless Network Interface Cards (WNICs) and by using multiple channels. This is in order to minimize interference and to provide high performance. However, multiple WNICs in each node require a channel assignment planning. The channels have to be assigned in such a way that interferences decrease and the performance increases at the same time. Since the number of available channels is limited, it is desired to dynamically allocate channels on demand. In this research, we address the problem of assigning channels to nodes in WMNs. For this purpose, we introduce the Distributed Cluster Channel Assignment (CCA) algorithm with the objective of reducing network interferences to increase the overall performance of the network. This clustering approach is employed in order to simplify the method of solving the channel assignment problem in terms of complexity. One of the advantages of this approach is that the possibility to reuse the channels in different clusters. In addition, a dynamic channel assignment is proposed for the aforementioned problem. This approach is called Neighborhood Nodes Collaboration to Support QoS (NNCQ). NNCQ is adaptive to the load in WMNs and supports Quality of Service (QoS) routing. The algorithm adds or selects a channel for heavily loaded nodes based on the local information of the neighbor nodes. The selected or added channel minimizes interferences and ensures network connectivity.