Hierarchical power control for OFDM based LTE system

3GPP LTE has approved uplink intra-cell power control and defined overload indicator (OI) for uplink inter-cell power control to mitigate the inter-cell interference (ICI), respectively. In this paper, we propose a hierarchical power control (HPC) scheme where intra-cell and inter-cell power controls interact with each other. The inter-cell power control command is generated by radio resource management (RRM) entity according to the ICI-load model together with the current ICI and served load information. This ICI-load model is proposed as a guideline for coordination among cells to enable the system to approach its system specific interference over thermal noise (IoT) work area. Simulation results show that for HPC scheme, the system's IoT is well controlled to fit its pre-defined work area and the power efficiency is improved significantly. Our proposed scheme is also robust to different settings of its inter-cell power control period.