Single and Dual Connectivity for Decoupled Uplink and Downlink Access in UHF-mmWave Hybrid Networks

Millimeter-wave communication is limited by high penetration and pathloss but can be used in base stations closer to the user terminals through heterogeneous networks to maximize spectrum usage and enrich coverage. This paper compares the performance of single and dual connectivity from both perspectives of pathloss and capacity. We also expand our capacity based association approach proposed in [12] to work in UHF-mmWave hybrid networks where mobile users can connect to different ultra high frequency small cells, millimeter-wave small cells and ultra high frequency macro cells with the option of decoupling. The results provide an insight into the performance of such techniques and network typologies for various performance metrics of interest. It will be shown that dual connectivity is not always superior and that single and dual hybrid connectivity can be a better choice. It will also be shown that wireless networks with both ultra high frequency and millimeter-wave small cells achieve higher capacity than those with only one kind of small cells.