Annual Report 2010 - Fachgruppe Informatik an der RWTH Aachen ...

Channel Assignment and Security in Multi-Channel Multi-Radio Wireless
Mesh Networks
Sadeq Ali Makram
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.
This research also addresses the security vulnerabilities in WMNs in general and of channel
assignment in particular. Security in channel assignment is an indispensable area of research
in wireless networks. However, this area has been overlooked by the researchers and
scientists in WMNs. The previously proposed schemes for dynamic channel assignment in
WMNs have not really considered the vulnerabilities that can exist inside these networks. We
have proposed an efficient, lightweight and secure assignment of channels in WMNs that
mitigates the channel assignment attacks. This is inevitable in order to achieve the benefits of
Multi-Radio Multi-Channel WMNs.
Evaluators: Prof. Dr. Otto Spaniol (RWTH Aachen University)
Prof. Dr. Petri Mähönen (RWTH Aachen University)
Date of oral exam: 28 May 2010
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