作者: Chun Meng , Abinesh Ramakrishnan , Athina Markopoulou , Syed Ali Jafar
DOI: 10.1109/ISIT.2012.6283630
关键词: Mathematics 、 Minimum cut 、 Theoretical computer science 、 Graph (abstract data type) 、 Directed acyclic graph 、 Unicast 、 Linear network coding 、 Directed graph 、 Precoding 、 Zero-forcing precoding
摘要: We consider the problem of network coding across three unicast sessions over a directed acyclic graph, when each session has min-cut one. Previous work by Das et al. adapted precoding-based interference alignment technique, originally developed for wireless channel, specifically to this problem. refer approach as (PBNA). Similar setting, PBNA asymptotically achieves half minimum cut; different from its feasibility depends on graph structure. provided set conditions with respect particular precoding matrix. However, consisted an infinite number conditions, which is impossible check in practice. Furthermore, were purely algebraic, without interpretation regards In paper, we first prove that Das. al are also necessary any Then, using two graph-related properties and degree-counting reduce just four conditions. This reduction enables efficient algorithm checking given graph.