Energy Efficiency Analysis of Heterogeneous Cellular Networks with Downlink and Uplink Decoupling

As current cellular networks are becoming increasingly heterogeneous, traditional cell association rule based on the downlink reference signal receiving power (RSRP) no longer serves well. Under this circumstance, the concept of downlink (DL) and uplink (UL) decoupling (DUDe), in which user equipments choose the serving Base Station (BS) in DL and UL separately, has drawn great attention during the design of next generation cellular networks. In this paper, using the framework of stochastic geometry, we at first derive the theoretical energy efficiency (EE) distribution of a two-tier heterogeneous network both in DL and UL with DUDe. Then through numerical simulation, we verify that the DUDe rule can improve EE of a heterogeneous network comparing with the traditional RSRP rule. The improvement is shown to be significant through a further comparison with bias-based Cell Range Extension (CRE).