A Heuristic Coordination Framework for Self-Optimizing Mechanisms in LTE HetNets

A self-organizing network (SON) is effectively realized by means of specific SON mechanisms (SON_m), which relate to particular SON use cases (SON_uc), these being defined by the Third-Generation Partnership Project (3GPP) and Next Generation Mobile Networks (NGMN). Typically, SON_uc are grouped into self-configuration, self-optimization, and self-healing functions. Focusing on self-optimization, SON_m therein aim at maintaining relevant key performance indicators (KPIs) above/below a specific target by actuating over an appropriate set of input parameters to achieve predefined network objectives. Typically, this problem is represented by several control loops where controllable input parameters are dynamically adjusted according to output measurable metrics and their corresponding target requirements. From an implementation viewpoint, the concept of a single SON “black box,” integrating multiple SON_m, is very appealing. However, this approach may threaten the control that network operators (NOPs) have over their own network. As a result, a coordinated framework involving stand-alone SON_m is proposed. Here, a SON controller (SON_c) may be implemented responding to strategies, deciding at a given time which SON_m actions have higher priority with respect to others. In the context of a heterogeneous network (HetNet) scenario, we propose and develop a simplified framework where stand-alone SON_m react to either overshot or undershot KPI events by deciding to either increase or decrease corresponding influential parameter(s). By inspecting the arising interactions and possible conflicts between several SON_m, we provide, for a specific evaluation scenario, a heuristic strategy-based solution for SON coordination, which may eventually trade off high-level NOP goals.