Multi-Operator Spectrum Sharing for Energy Efficient Heterogeneous Cellular Networks

The dense deployment of eNodeBs (eNBs) and small cells (SCs) is expected to be the core element of fifth generation (5G) networks. Given the massive SC deployment, the aggregate power consumption attributed to SCs in the coverage area of a macrocell becomes considerable, thus raising issues for the network energy efficiency. However, the coexistence of multiple mobile network operators (MNOs) in the same geographic area fosters cooperation agreements that suggest further energy and cost saving. Several 5G initiatives (from industry and academia) have been pushing for solutions to enable network slicing in mobile networks, mainly based on Software Defined Networking (SDN), Network Functions Virtualization (NFV), and cloud computing as key enablers. While several techniques of slicing the network infrastructure exist, slicing the Radio Access Network (RAN) is still challenging. In this paper we attempt to study the energy efficiency aspects in the case of next generation outdoor Long Term Evolution (LTE) heterogeneous networks (HetNets) owned by rival MNOs. In particular, we propose a multiobjective optimization framework aimed at minimizing the power consumption that applies to both eNBs and SCs and exploits resource sharing to guarantee the provided quality of service (QoS). It is shown that the proposed solution achieves notable energy saving, without compromising the QoS to the network users.