Inter-tier interference coordination has been a vital design problem to ensure the edge-user service quality in heterogeneous networks. In this regard, the almost blank subframe (ABS) approach, which relies on the time domain coordination between base station tiers, has been shown to be among the most effective inter-tier interference coordination techniques. In this paper, we first present analysis for the area spectral efficiency and area energy consumption using the stochastic geometry approach for a two tier heterogeneous network. With the outcome of the analysis, we then formulate an energy efficiency optimization problem with energy consumption and the worst-user performance constraints. By the constraints in the optimization problem, the feasible region for the number ABS’s is presented and the region boundaries are explained. The performance of multi-tier ABS is compared with single-tier ABS implementation where the advantages of both macro and pico ABS’s are discussed. The numerical results are presented for both open (pico-cells) and closed (femto-cells) access networks with performance comparison.

层间干扰协调一直是确保异构网络中边缘用户服务质量的重要设计问题。在这方面，依赖于基站层之间时域协调的几乎空白子帧 (ABS) 方法已被证明是最有效的层间干扰协调技术之一。在本文中，我们首先使用随机几何方法对两层异构网络进行区域频谱效率和区域能量消耗的分析。根据分析的结果，我们然后制定了能源消耗和最差用户性能约束的能源效率优化问题。通过优化问题中的约束，给出了数量ABS的可行区域并解释了区域边界。多层 ABS 的性能与单层 ABS 实现进行了比较，其中讨论了宏 ABS 和微微 ABS 的优点。数值结果针对开放（微微蜂窝）和封闭（毫微微蜂窝）接入网络进行了性能比较。