ISPAN '00 Proceedings of the 2000 International Symposium on Parallel Architectures, Algorithms and Networks
Proceedings of the 5th ACM international symposium on Mobile ad hoc networking and computing
Routing in multi-radio, multi-hop wireless mesh networks
Proceedings of the 10th annual international conference on Mobile computing and networking
Proceedings of the 10th annual international conference on Mobile computing and networking
Capacity of multi-channel wireless networks: impact of number of channels and interfaces
Proceedings of the 11th annual international conference on Mobile computing and networking
Proceedings of the 11th annual international conference on Mobile computing and networking
On the Fidelity of IEEE 802.11 Commercial Cards
WICON '05 Proceedings of the First International Conference on Wireless Internet
Partially overlapped channels not considered harmful
SIGMETRICS '06/Performance '06 Proceedings of the joint international conference on Measurement and modeling of computer systems
Experimental characterization of an 802.11b wireless mesh network
Proceedings of the 2006 international conference on Wireless communications and mobile computing
Long-distance 802.11b links: performance measurements and experience
Proceedings of the 12th annual international conference on Mobile computing and networking
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Several scientific works have considered the possibility to build Wireless Mesh Networks (WMN) using multi-channel IEEE 802.11 architectures. At the basis of these works is the notion of ''non-overlapping'' channels, i.e. with a frequency separation equal or greater than 25MHz. It is now a common assumption that multiple independent transmissions over these channels can coexist without mutual interference even in physical proximity. In this work we demonstrate that this assumption does not hold in general. Through an extensive set of experiments we illustrate the presence of cross-channel interference between ''non-overlapping'' channels at relay nodes due to the ''near-far'' effect. We analyze in what manner the MAC layer reacts to such an interference and how this problem extends to higher layers, with detrimental effects on the global throughput. The central problem is that cross-channel interference is not handled adequately by the MAC layer, and in some cases single-channel multi-hop settings perform better than multi-channel. Our results highlight a serious mismatch between some routing and channel assignment schemes proposed recently by the research community, assuming full separation between non-overlapping channels, and what is achievable in practice. More generally, as the presence of cross-channel interference can not be neglected at relay nodes, our findings point to a fundamental problem in building Multi-channel Multi-hop WMN based on IEEE 802.11b/g technology.