Discrete & Computational Geometry

, Volume 48, Issue 1, pp 39–52

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


    • Centre for Unified ComputingUniversity College Cork
  • Khaled Elbassioni
    • Max-Planck-Institut für Informatik
  • Sathish Govindarajan
    • Computer Science DepartmentIndian Institute of Science
  • Saurabh Ray
    • Max-Planck-Institut für Informatik

DOI: 10.1007/s00454-012-9425-5

Cite this article as:
Ajwani, D., Elbassioni, K., Govindarajan, S. et al. Discrete Comput Geom (2012) 48: 39. doi:10.1007/s00454-012-9425-5


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 networksConflict-free coloringAxis-parallel rectanglesBoundary setsMonotone sequences

Copyright information

© Springer Science+Business Media, LLC 2012