On the local delay and energy efficiency of clustered HetNets

Due to the dense and generally random deployment of base stations (BSs) in heterogeneous networks (HetNets), stochastic geometry has increasingly been used to analyze the performance of HetNets. Considering the geographical distribution of BSs, however, the commonly assumed Poisson point process (PPP) may not be accurate enough. In contrast, a Poisson cluster process (PCP) proves more realistic for the deployment of BSs. In this paper, by using the discontinuous transmission (DTX) mode, the local delay and energy efficiency based on PCP have been analyzed. The expressions of local delay and energy efficiency have been derived, and it is found theoretically and via simulations that the local delay is larger and the energy efficiency is lower under PCP compared to PPP because of the strong intracluster interference. In addition, we found that the performances of PCP-based HetNets are close to those of PPP for the high mute probability case and low signal-to-interference ratio threshold case, where the impact of clustering diminishes. Moreover, the energy efficiency can be optimized further with a low local delay by jointly adjusting the mute probability and BS density within a cluster. Finally, we found that the local delay could decrease with the increase of the density of BSs by setting the proper mute probability, which is different from the PPP case.