In order to tackle the explosive growth of data traffic and the number of terminals, 5G heterogeneous network (HetNet) has become an important evolution direction of 5G networking architecture. Densely deployed micro base stations (gNBs) in 5G HetNets will dramatically increase the handover frequency of user equipment (UE), resulting in more handover failures, and seriously reducing the user experience of mobile UE. Aiming at tackling this problem, this paper proposes a beam enhancement handover scheme with an adaptive threshold. Firstly, different beamforming gains are configured for the mobile UE in the overlapping area of two gNBs to improve the signal strength received by the UE at the edge of gNB coverage. Secondly, for mobile UE with different speeds, adaptive handover decision parameters are configured, and reference signal receiving strength (RSRP) as well as reference signal receiving quality (RSRQ) are used for joint handover decisions to achieve reliable handover. The simulation results verify that the proposed scheme can effectively improve the signal strength of the edge area, and the adaptive joint handover decision algorithm based on UE speed can also effectively improve the handover success probability.

With the exponential growth of user equipment (UE) access in future networks, service operators are deploying many low-cost and low-power heterogeneous base stations. However, when considering cooperative multi-point (CoMP) based soft handover schemes, there will be a trade-off between user quality of service (QoS), system power consumption, and handover frequency. Therefore, in this letter, we proposed a CoMP-based energy-efficient intelligent handover algorithm, named CEH-PPO in heterogeneous cellular networks. The proposed scheme is based on the Proximal Policy Optimization (PPO) algorithm in deep reinforcement learning. The optimization objective is to maximize the average user rates and minimize energy consumption and handover frequency in the CoMP-based heterogeneous network. Thus, we can dynamically select the transmission base station set for UEs to accomplish the handover procedure. Simulation results demonstrate that the proposed CEH-PPO algorithm simultaneously improves the average QoS of UEs in the system and reduces the overall handover frequency while reducing the overall power consumption.