Turning off Radios to Save Power in Multi-Radio Wireless Mesh Networks

Endowing mesh routers with multiple radios is a recent solution to improve the performance of wireless mesh networks (WMNs). The problem how to route flows and assign channels to radios in multi-radio WMNs has attracted a lot of attention in the recent years. However, the approaches proposed so far have mainly focused on reducing interference or maximizing the throughput. Little attention has been paid to the energy consumption of wireless mesh networks. However, with the rising concerns about the energy consumed by communication infrastructures, it makes sense to consider the minimization of the energy consumption as an objective of the channel assignment and routing problem. Our work stems from the observation that an idle radio simply overhearing a frame consumes nearly the same power as the radio actually receiving the frame. Hence, energy may be saved by turning off a number of radios, if the performance of the network is not impaired. In this paper, we define the energy-efficient channel assignment and routing problem, which is NP-complete, and propose a heuristic algorithm. We also present a Mixed Integer Linear Programs (MILP) to find an optimal solution to the energy-efficient channel assignment and routing problem. Finally, we show the results of extensive simulation studies we conducted to assess the effectiveness of the proposed algorithm. Such results show that our heuristic outperforms a previous proposal and that, on the average, it keeps 10% more radios turned on than the optimal solution