Discrete & Computational Geometry

, Volume 48, Issue 1, pp 39–52 | Cite as

Conflict-Free Coloring for Rectangle Ranges Using O(n.382) Colors

  • Deepak Ajwani
  • Khaled Elbassioni
  • Sathish Govindarajan
  • Saurabh Ray


Given a set of points P⊆ℝ2, a conflict-free coloring of P w.r.t. rectangle ranges is an assignment of colors to points of P, such that each nonempty axis-parallel rectangle T in the plane contains a point whose color is distinct from all other points in PT. This notion has been the subject of recent interest and is motivated by frequency assignment in wireless cellular networks: one naturally would like to minimize the number of frequencies (colors) assigned to base stations (points) such that within any range (for instance, rectangle), there is no interference. We show that any set of n points in ℝ2 can be conflict-free colored with \(O(n^{\beta^{*}+o(1)})\) colors in expected polynomial time, where \(\beta^{*}=\frac{3-\sqrt{5}}{2} < 0.382\).


Frequency assignment in wireless networks Conflict-free coloring Axis-parallel rectangles Boundary sets Monotone sequences 


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Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Deepak Ajwani
    • 1
  • Khaled Elbassioni
    • 2
  • Sathish Govindarajan
    • 3
  • Saurabh Ray
    • 2
  1. 1.Centre for Unified ComputingUniversity College CorkCorkIreland
  2. 2.Max-Planck-Institut für InformatikSaarbrückenGermany
  3. 3.Computer Science DepartmentIndian Institute of ScienceBangaloreIndia

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