External Interference-Aware Distributed Channel Assignment in Wireless Mesh Networks

Interference is one of the major causes for performance degradation in wireless networks. Channel assignment algorithms have been proven successful to decrease the networkwide interference by using non-overlapping channels for otherwise interfering links. However, external co-located networks and devices are usually not considered in the channel assignment procedure, since they are not under the control of the network operator and their activity is therefore hard to capture. In our work we fill this gap by additionally considering the interference resulting from external devices. The novelty of this approach is that not only co-located IEEE 802.11 networks are captured, but also other sources of interference that utilize the same frequency band. We present the spectrum sensing component DES-Sense, a software solution for 802.11a/b/g that detects congested channels and does not require any changes to the drivers. We present a first algorithm for external interference-aware channel assignment and show proof-of-concept results from the DES-Testbed, a wireless mesh network with 120 multi-radio nodes.