Analysis of Area Spectral Efficiency and Energy Efficiency in Heterogeneous Ultra-Dense Networks

With the exponential increasing of the mobile traffic from the wireless equipment, the cellular networks face a great challenge to meet the every-increasing throughput demand. A potential way is Ultra-Dense deployment of the small-cell in the existing macro-cell. By modeling the base stations (BSs) from both macro-cells and small-cells as homogeneous Poisson Point Process (PPP), we analytically evaluate the area spectral efficiency (ASE) and energy efficiency (EE) of downlink wireless system using stochastic geometry theory. It is shown that the ASE is increasing with the small cell density. It means that deploying more small-cells in the macro-cell coverage area is a feasible way to improve the system throughput. However, with the increasing of small cell density, the EE goes to an optimal point and then start to decrease. We introduce a firefly-inspired algorithm named Firefly Algorithm (FA) to analyze the ASE and the EE impacted by the BSs density and the transmitting power.