Mobility handover optimization in millimeter wave heterogeneous networks

In this paper, we develop a new mobility-aware handover algorithm for users in microwave and millimeter wave (mmWave) heterogeneous networks. The proposed handover algorithm applies a Markov decision process (MDP) and a Gauss-Markov mobility model to optimize handovers based on user velocity, location, SNR and estimated time spent in the mmWave small cell (known as the small cell dwell time). Practical mmWave beam alignment overheads and blockage effects are also taken into account in the MDP formulation and optimization. Simulation results verify that the proposed MDP-based handover algorithm achieves significantly higher data rates compared with traditional SNR-based handovers for low to high velocity users.