Dynamic Femtocell gNB On/Off Strategies and Seamless Dual Connectivity in 5G Heterogeneous Cellular Networks

To meet the drastic growth of the mobile traffic, 5G network is designed to optimize the transmission efficiency and provide higher quality of service (QoS). Small cell is considered as a promising and feasible approach to meet the increasing traffic demand. For this purpose, in this paper, we study a, OFF dynamic Femtocell gNB (F-gNB) ON/OFF strategies in 5G heterogeneous cellular networks (HCNs), which aims at maximizing the network energy efficiency (NEE) by optimizing jointly the traffic load prediction,, OFF the cell association, and the dynamic F-gNB ON/OFF strategies with respected to the time-varying traffic load, while taking into account the load balancing and the outage probability of the network. However, the optimization problem is a nonconvex problem. In order to relax the computation complexity, the original optimization problem is divided into two steps: cell association with load balancing (CALB) scheme and energy efficiency-based dynamic F-gNBs ON/OFF (DFOO) strategies. Specifically, the proposed CALB scheme could guarantee the load balancing as well as the minimum signal-to-interference-plus-noise ratio requirement of user equipments (UEs). In addition, the proposed DFOO strategies consider the operation of base stations (BSs) according to the predicted time-varying traffic load from Markov procedure. Furthermore, dual connectivity-based seamless handover procedure is introduced to guarantee the transmission QoS of UEs. Simulation results illustrate that the proposed DFOO algorithm provide considerable improvement of NEE while ensuring the load balancing of the HCN.