Fast heuristics for the frequency channel assignment problem in multi-hop wireless networks

Communication links connect pairs of wireless nodes in a wireless network. Links can interfere with each other due to their proximity and transmission power if they use the same frequency channel. Given that a frequency channel is the most important and scarce resource in a wireless network, we wish to minimize the total number of different frequency channels used. We can assign the same channel to multiple different links if the assignment is done in a way that avoids co-channel interference. Given a conflict graph which shows conflicts between pairs of links if they are assigned the same frequency channel, assigning channels to links can be cast as a minimum coloring problem. However the coloring problem is complicated by the fact that acceptably small levels of interference between pairs of links using the same channel can accumulate to cause an unacceptable level of total interference at a given link. In this paper we develop fast and effective methods for frequency channel assignment in multi-hop wireless networks via new heuristics for solving this extended coloring problem. The heuristics are orders of magnitude faster than an exact solution method while consistently returning near-optimum results.