Joint Routing and Link Scheduling for Wireless Mesh Networks through Genetic Algorithms

Wireless mesh networks (WMN) are emerging as an attractive technology for providing broadband connectivity to mobile clients who are just on the edge of wired networks, and also for building self-organized networks in places where wired infrastructures are not available or not deemed to be worth deploying. This paper investigates the joint link scheduling and routing issues involved in the delivery of a given backlog from any node of a WMN towards a specific node (which acts as a gateway), within a given deadline. As in a real WMN, scheduling and routing are assumed to be aware of the physical interference among nodes, which is modeled in the paper by means of a signal-to-interference ratio (SIR). Firstly, using a theoretical model of a WMN we formulate the problem as an integer linear programming (ILP) problem. Secondly, since the problem cannot be dealt with using exact methods, we propose and use a technique based on genetic algorithms (GAs). To the best of our knowledge, GAs have never been used before for working out these kinds of optimization problems in a WMN environment. We show that our technique is suitable for this purpose as it provides a good trade-off between fast computation and the overall goodness of the solution found. Our experience has in fact shown that GAs would seem to be quite promising for solving more complex WMN models than the one dealt with in this paper, such as those including multiple flows and multi-radio multi-channels.