LTE-Advanced Self-Organising Network Conflicts and Coordination Algorithms

Self-Organising Network (SON) functions have been introduced in the Long Term Evolution (LTE) and LTE-Advanced standards by the Third Generation Partnership Project (3GPP) as an excellent solution that promises enormous improvements in the network performance. However, the most challenging issue in implementing SON functions in reality is the identification of the best possible interactions among simultaneously operating and even conflicting SON functions in order to guarantee a robust, stable and desired network operation. In this direction, the first step is the comprehensive modelling of various types of conflicts among SON functions, not only to acquire a detailed view of the problem, but also to pave the way for designing appropriate Self-Coordination mechanisms among SON functions. In this paper we present a comprehensive classification of SON function conflicts, which leads the way for designing suitable conflict resolution solutions among SON functions and implementing SON in reality. Identifying conflicting and interfering relations among autonomous network management functionalities is a tremendously complex task. We demonstrate how analysis of fundamental trade-offs among performance metrics can lead us to the identification of potential conflicts. Moreover, we present analytical models of these conflicts using Reference Signal Received Power (RSRP) plots in multi-cell environments which help to dig into the complex relations among SON functions. We identify potential chain reactions among SON function conflicts that can affect the concurrent operation of multiple SON functions in reality. Finally, we propose a Self-Coordination framework for conflict resolution among multiple SON functions in LTE/LTE-Advanced networks, while highlighting a number of future research challenges for conflict-free operation of SON.