Gateway selection scheme for throughput optimization in multi-radio multi-channel wireless mesh networks under physical interference model

In this paper, we investigate the gateway selection problem for throughput optimization in multi-radio multichannel wireless mesh networks. In contrast to the various methodologies in the literature, we not only explicitly model the delay overhead that is incurred during channel switching, and consider this delay-related issue in the design of our mechanism but also employ the most reliable interference model in our approach, e.g., physical interference model. From our best knowledge, it is the first time to take account switching overhead into the scenario of gateway selection in multi-radio multi-channel wireless networks under physical interference model. Given the number of gateways to be deployed in the network system and the interference model adopted for the communication, we study how to select a proper subset of mesh nodes to be equipped with gateway functionality in the network such that the total network throughput is maximized meanwhile a certain fairness among all mesh nodes can be also guaranteed. In this paper, we formulate the scenario mentioned above as a NP-hard optimization problem. Due to extremely high computational burden to generate an optimal solution, we propose a new gateway selection scheme (e.g., a new approximation algorithm) using a cross-layer throughput optimization. Combining with a new interference-aware link-channel scheduling algorithm we proposed in this work, we show that the performance on the achieved network throughput by our gateway selection scheme is only a logarithmical factor far to the optimum in terms of the size of network.