The growth of mobile devices and their traffic volume make it necessary for mobile network operators to provide higher capacity. As traditional macrocell-based cellular networks could not support a massive number of mobile users, Heterogeneous Networks (HetNets) are welcomed as a coexistence of macro-cells and small-cells in 5G mobile networks. The main challenge of 5G HetNets is the management of co-tier and cross-tier interference. Fractional Frequency Reuse (FFR) is a suitable technique to mitigate the interference along with improving spectrum efficiency. On the other side, energy consumption has attracted much attention in 5G green cellular networks. Efficient power allocation and cell zooming/cell switch-off techniques are of the most important research directions in this area. However, the impact of cell zooming/switch-off on FFR-based HetNets has not been attended adequately. In this paper, a solution is presented which exploits dynamic adjustment of cell-center radius and efficient power allocation in FFR-based HetNets when conducting a cell switch-off/cell zooming. A heuristic algorithm is presented for cell-center radius adjustment problem. Also, for efficient power allocation, a multi-objective optimization problem is formulated and solved using NSGA-II algorithm Simulation results show that the proposed method reduces energy consumption compared to the baseline method and diminishes the overall interference in the system.

移动设备及其流量的增长使得移动网络运营商有必要提供更高的容量。由于传统的基于宏蜂窝的蜂窝网络无法支持大量的移动用户，因此异构网络（HetNets）作为5G移动网络中宏蜂窝和小型蜂窝的共存而受到欢迎。5G HetNets的主要挑战是对共层和跨层干扰的管理。小数频率复用（FFR）是缓解干扰并提高频谱效率的合适技术。另一方面，能源消耗在5G绿色蜂窝网络中引起了很多关注。高效的功率分配和小区缩放/小区关闭技术是该领域最重要的研究方向。然而，单元缩放/关闭对基于FFR的HetNets的影响尚未引起足够的重视。在本文中，提出了一种解决方案，该解决方案在执行单元关闭/单元缩放时利用基于FFR的HetNets中的单元中心半径的动态调整和有效的功率分配。针对单元中心半径调整问题，提出了一种启发式算法。此外，为了有效地分配功率，使用NSGA-II算法提出并解决了一个多目标优化问题。仿真结果表明，与基线方法相比，该方法降低了能耗，并减少了系统中的总体干扰。提出了一种解决方案，该解决方案在进行小区关闭/小区缩放时利用基于FFR的HetNet中的小区中心半径的动态调整和有效的功率分配。针对单元中心半径调整问题，提出了一种启发式算法。此外，为了有效地分配功率，使用NSGA-II算法提出并解决了一个多目标优化问题。仿真结果表明，与基线方法相比，该方法降低了能耗，并减少了系统中的总体干扰。提出了一种解决方案，该解决方案在进行小区关闭/小区缩放时利用基于FFR的HetNet中的小区中心半径的动态调整和有效的功率分配。针对单元中心半径调整问题，提出了一种启发式算法。此外，为了有效地分配功率，使用NSGA-II算法提出并解决了一个多目标优化问题。仿真结果表明，与基线方法相比，该方法降低了能耗，并减少了系统中的总体干扰。