Management of Future Mesh-Based Radio Access Networks

55 Wireless mesh networks combine three key features: the use of wireless transmission , the multi-hop nature of the end-to-end communication, and the availability of multiple paths. While each of these features raises a host of technical issues, at the same time they provide those advantages that make wireless mesh networks appealing. For instance, wireless transmission offers ubiquitous coverage for both stationary and mobile users; multi-path communication provides dependability in terms of increased network availability and reliability of wireless access to the Inter-net; and wireless multi-hop communication enables operation with reduced interference and low management costs. The overall mesh network management consists of the initial configuration, and subsequently adaptation, of procedures and mechanisms to achieve operation of the network according to some performance objectives. In this direction, we are investigating and developing new solutions for key network management functionalities, which include the following: • power and rate control in metropolitan wireless mesh networks • channel assignment in metropolitan wireless mesh networks with directional antennas and mesh networks with omni-directional antennas • topology control in wireless mesh networks with omni-directional antennas. Key features of our approach include the investigation of the cross-layer interaction of various mechanisms, the investigation of the timescales of management functions, and the combination of analysis and simulation, together with testbed implementation and evaluation. The experimental testbeds include a fourteen-node indoor network with mesh nodes containing four radio interfaces , and a metropolitan mesh network. The latter covers an area of approximately 60 km2 in the city of Heraklion in Crete, Greece and contains fourteen nodes, of which six are core mesh nodes, each containing up to four radio interfaces. The mesh network has two fixed network gateway nodes: one at the Foundation for Research and Technology -Hellas (FORTH) and one at the University of Crete. Another important feature of the metropolitan testbed is an independent overlay network that is used for management and monitoring. With respect to rate and power control in metropolitan wireless mesh networks with directional links, our results indicate that there are no performance gains when these mechanisms are performed on small timescales, of the order of packet transmission times. Indeed, adaptation of the transmission rate in very small timescales can actually reduce the achievable throughput in the case of low-quality links. For power control, we find that the minimum transmission power to achieve a target minimum performance does not change significantly during the …