Exact and heuristic algorithms for Space Information Flow

• Published in: PloS one Vol. 13; no. 3; p. e0193350
• Main Authors: Uwitonze, Alfred, Huang, Jiaqing, Ye, Yuanqing, Cheng, Wenqing, Li, Zongpeng
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27.03.2018; Public Library of Science (PLoS)
• Subjects: Algorithms; Biology and Life Sciences; Butterflies; Coding; Complexity; Computation; Computer and Information Sciences; Computer applications; Computer networks; Computer simulation; Decision trees; Delaunay triangulation; Design; Euclidean geometry; Flow rates; Heuristic; Heuristic methods; Information flow; Information technology; Information theory; International conferences; Linear programming; Mathematical research; Multicast; Multicasting; Nodes; Physical Sciences; Problems; Research and Analysis Methods; Telecommunications transmission technologies; Topology; Triangulation; Wireless networks; China; Rwanda
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0193350

Space Information Flow (SIF) is a new promising research area that studies network coding in geometric space, such as Euclidean space. The design of algorithms that compute the optimal SIF solutions remains one of the key open problems in SIF. This work proposes the first exact SIF algorithm and a heuristic SIF algorithm that compute min-cost multicast network coding for N (N ≥ 3) given terminal nodes in 2-D Euclidean space. Furthermore, we find that the Butterfly network in Euclidean space is the second example besides the Pentagram network where SIF is strictly better than Euclidean Steiner minimal tree. The exact algorithm design is based on two key techniques: Delaunay triangulation and linear programming. Delaunay triangulation technique helps to find practically good candidate relay nodes, after which a min-cost multicast linear programming model is solved over the terminal nodes and the candidate relay nodes, to compute the optimal multicast network topology, including the optimal relay nodes selected by linear programming from all the candidate relay nodes and the flow rates on the connection links. The heuristic algorithm design is also based on Delaunay triangulation and linear programming techniques. The exact algorithm can achieve the optimal SIF solution with an exponential computational complexity, while the heuristic algorithm can achieve the sub-optimal SIF solution with a polynomial computational complexity. We prove the correctness of the exact SIF algorithm. The simulation results show the effectiveness of the heuristic SIF algorithm.