On the Local Delay and Energy Efficiency of HetNets with User Mobility

With the development of fifth generation (5G) communications systems, heterogeneous networks (HetNets) have become a research hotspot. However, most of the existing work assumes that the user is static in HetNets. This hypothesis can greatly simplify system models, nevertheless it is not always accurate enough, because the user mobility has a significant effect on the performances of HetNets. Therefore, this paper studies the influence of the infinite user mobility in HetNets by using tools from stochastic geometry. The local delay and energy efficiency of HetNets based on Poisson point process (PPP) and Poisson cluster process (PCP) respectively are derived, the latter being more accurate to model the hot spot areas than the former. It was found that user mobility can reduce obviously the local delay and improve the energy efficiency under the high SIR regime. Moreover, the local delay is larger and the energy efficiency is lower under PCP than under PPP for infinite user mobility. In addition, the user mobility can reduce the function of the discontinuous transmission (DTX) scheme, which is used to improve the energy efficiency. Finally, the simulation results verify the accuracy of the numerical analyses.