Efficiency analysis of a K-tier clustered HCN using dual connectivity with DUDe access

Abstract

The Heterogeneous Cellular Network (HCN) paradigm holds promise for increasing the coverage probabilities and date rates of its users. The concept of downlink and uplink decoupling (DUDe) has been extensively investigated to alleviate the load imbalance problem in HCNs. Furthermore, the dual connectivity (DC) access scheme, which allows user equipment (UE) to simultaneously connect with multiple base stations (BSs), has also been investigated for its bandwidth aggregation feature that can provide increased UE data rates. This work uses stochastic geometry to analyze the uplink spectral- and energy-efficiency gains provided in a K-tier HCN with clustered users by introducing DC jointly with DUDe access. The BSs in each tier are modeled by an independent, homogeneous Poisson point process, whereas the spatially clustered UEs are modeled by a Matern cluster process. The exact analytical expressions and the upper-bound on coverage probability, spectral and energy efficiencies of the typical user are derived. The main results demonstrate the relative advantage of using DC with DUDe relative to the cases of single connectivity (SC) with DUDe and SC with the conventional downlink reference received power-based association. Further, the results also show that clustering should be modeled with an MCP to analyze the performance of clustered-HCNs.