A Functional Architecture for Self-Coordination in LTE networks

Inhalt:
In a self-organized Long Term Evolution (LTE) network, different Self-Organizing Network (SON) functions can execute parallel actions which interact or collide among each other. When the effect of the interaction negatively affects the performances of the system, this is referred to in 3rd Generation Partnership Project (3GPP) as a SON conflict, which needs to be handled by means of a self-coordination framework. We focus in this paper on a functional architecture for the selfcoordination of different actions taken by different SON functions to be automatically executed in a self organized realistic LTE network. We propose a functional architecture and a theoretical framework based on the theory of Markov Decision Process (MDP)s. In order to cope with the size of the state spaces, we subdivide the Markov Decision problem modeling the eNB onto simpler subMDPs modeling the different SON functions. Each sub-problem is defined as an MDP and solved independently, and their individual policies are combined to obtain a global policy. This combined policy can execute several actions per state but can introduce policy conflicts. We focus on the specific SON conflict generated by the concurrent execution of multiple SON functions, which may require to update the same parameter. The coordination among the different actions selected by the conflicting use cases is achieved by means of two approaches. The first one is based on a modified policy iteration protocol. The second one is based on a coordination game where the players are the subMDPs and the actions and rewards are those provided by the independent subMDP solutions.