Abstract-We investigate the problem of channel assignment in a metropolitan wireless multi-radio mesh network with directional antennas. We first present a new conflict graph model for capturing the interference between links in a mesh network with a known wireless interface communication graph. Then we present a channel assignment procedure which accounts for interference both between links internal to the mesh network, and from external sources. Key components of the channel assignment procedure are the interference model, the link ordering, and the channel selection metric. We have implemented and evaluated the proposed channel assignment procedure in an actual metropolitan mesh network with link distances from 1.6 to 5 Km. The experimental results demonstrate how link ordering and the channel selection metric affect performance, in terms of the average packet delay and http latency. Moreover, the experimental results show that the proposed channel assignment procedure achieves performance that is within approximately 11% of a lower bound of the average packet delay, and significantly higher than the performance achieved with a simpler interference-unaware procedure.

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