Distributed graph coloring for self-organization in LTE networks

Primary component carrier selection and physical cell id assignment are two important self-configuration problems pertinent to lte-advanced. in this work,we investigate the possibility to solve these problems in a distributive manner using a graph coloring approach. algorithms based on real-valued interference pricing of conflicts converge rapidly to a local optimum,whereas algorithms with binary interference pricing have a chance to find a global optimum. we apply both local search algorithms and complete algorithms such as asynchronous weak-commitment search. for system level performance evaluation,a picocellular scenario is considered,with indoor base stations in office houses placed in a manhattan grid. we investigate a growing network,where neighbor cell lists are generated using practical measurement and reporting models. distributed selection of conflict-free primary component carriers is shown to converge with 5 or more component carriers,while distributed assignment of confusion-free physical cell ids is shown to converge with less than 15 ids. the results reveal that the use of binary pricing of interference with an attempt to find a global optimum outperforms real-valued pricing. © 2010 furqan ahmed et al.