Channel Assignment and Topology Control for Multi-Hop Multi-Radio Mesh Networks

Multi-radio mesh networks afford the opportunity to create frequency diversity within the mesh network by assigning different links in the network to different channels without affecting connectvity. This kind of frequency diversity results in reduced wireless self-interference and improved performance.

However, the problem of optimally assigning channels in a mesh composed of two-radio mesh nodes is complex, and in fact is NP-hard, which means that all practical solutions only attempt to approximate an optimal assignment.

In this project, I designed a suite of algorithms that combine topology and power control, traffic pattern expectations, and measurements of the interference properties of the mesh, to come up with an assignment of channels within the mesh such that interference is minimized and performance is optimized for a given topology, level of connectivity, and expected general traffic pattern. Both the initial assignment of channels in the network and subsequent adjustments to the assignment due to node or link failure can be performed in a centralized or distributed manner. Adjustments to the assignment after a failure preserve the properties of the assignment while localizing any channel changes required to preserve connectivity.

The channel assingment suite of algorithms is currently implemented in Firetide's mesh products, which are in deployment around the world.