Abstract
Channel assignment problems in multi-radio wireless mesh networks (WMNs) have been shown to be NP-hard in various scenarios in the literature. By far, most of research efforts have focused on developing efficient approximation algorithms that run reasonably fast and provide good quality channel assignment rather than the optimal one. However, from the practical network design and deployment standpoint, engineers care more about whether it is feasible to optimally assign channels in the simplest way (i.e., exhaustive search), as most of existing commercial WMNs are of small/medium scale. In this paper, we attempt to answer this practical question. We study the complexity of general channel assignment problems with certain basic and common properties. The results show that the complexity in terms of the number of different possible assignments is exponential in the number of wireless links. Furthermore, we estimate the theoretical runtime of determining the optimal channel assignment by exhaustive search and validate it through experiments. We show that, given certain computing power (e.g., an off-the-shelf notebook PC), it is feasible to optimally solve channel assignment problems in small-scale and medium-scale commercial multi-radio WMNs. In other words, approximation algorithms are not needed for most of current commercial WMNs.
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Xie, W., Zhang, Y.J.(., Sichitiu, M.L. et al. Feasibility of optimally assigning channels by exhaustive search in commercial multi-radio wireless mesh networks. Telecommun Syst 44, 171–178 (2010). https://doi.org/10.1007/s11235-009-9216-3
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DOI: https://doi.org/10.1007/s11235-009-9216-3