Downlink heterogeneous small cell networks with cell associations in K-floor indoor scenarios

To support the unrelenting demand of services with gigabit data rates in indoor scenarios, a dense heterogeneous small cell network (HSCN) is presented as a promising paradigm for the fifth generation system. In this paper, the coverage probability for the downlink HSCN with three cell association methods, namely the nearest association, the N-th nearest association and the maximum received power based association, is analyzed. Particularly, small cell base stations SCBSs randomly deployed in each floor are modeled as a spatial Poisson point process (PPP) distribution, and the stochastic geometry tool is used to evaluate the coverage probability. Different from the traditional outdoor scenario, the penetration loss is considered and the corresponding impact on the coverage probability is analyzed. The closed-form expressions of coverage probability for these three association methods are derived for HSCNs in the dense K-floor indoor scenarios. Simulation results validate the accuracy of our analysis and show that the coverage performance for the maximum received power based association method is much better than that of the N-th nearest association method regardless of the SCBS density in each floor. Meanwhile, the nearest association approaches the the maximum received power based association method when the SCBS density is high.