Discrete Mathematics & Theoretical Computer Science, Vol 15, No 3 (2013)

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1-local 33/24-competitive Algorithm for Multicoloring Hexagonal Graphs

Rafal Witkowski, Janez Zerovnik


In the frequency allocation problem, we are given a cellular telephone network whose geographical coverage area is divided into cells, where phone calls are serviced by assigned frequencies, so that none of the pairs of calls emanating from the same or neighboring cells is assigned the same frequency. The problem is to use the frequencies efficiently, i.e.~minimize the span of frequencies used. The frequency allocation problem can be regarded as a multicoloring problem on a~weighted hexagonal graph, where each vertex knows its position in the graph. We present a 1-local 33/24-competitive distributed algorithm for multicoloring a hexagonal graph, thereby improving the previous 1-local 7/5-competitive algorithm.

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