Energy Efficiency Analysis of Heterogeneous Cellular Networks With Extra Cell Range Expansion

Abstract

The split control and user plane is key to the future heterogeneous cellular\nnetwork (HCN), where the small cells are dedicated for the most data\ntransmission while the macrocells are mainly responsible for the control\nsignaling. Adapting to this technology, we propose a general and tractable\nframework of extra cell range expansion (CRE) by introducing an additional bias\nfactor to enlarge the range of small cells flexibly for the extra offloaded\nmacrousers in a two-tier HCN, where the macrocell and small cell users have\ndifferent required data rates. Using stochastic geometry, we analyze the energy\nefficiency (EE) of the extra CRE with joint low power transmission and resource\npartitioning, where the coverages of EE and data rate are formulated\ntheoretically. Numerical simulations verify that the proposed extra CRE can\nimprove the EE performance of HCN, and also show that deploying more small\ncells can provide benefits for EE coverage, but the EE improvement becomes\nsaturated if the small cell density exceeds a threshold. Instead of\nestablishing the detail configuration, this paper can provide some valuable\ninsights and guidelines to the practical design of future networks, especially\nfor the traffic offloading in HCN.\n