On the performance analysis of downlink heterogeneous networks with dual connectivity

By separately transmitting data and control signals from different tiers, dual connectivity (DC) delivers a potential solution to the handover and load balancing challenges brought by small cell deployment. In this paper, a tractable framework is developed for the downlink performance analysis of DC assisted heterogeneous cellular networks (HetNets). Based on a stochastic geometry model, accurate expressions of data-control joint coverage probability and average rate for a typical DC capable UE are derived and investigated under DC mode and single connectivity (SC) mode. It is observed that operating parameters like cell association bias and transmit power will change the optimum node density ratio to reach the maximum coverage probability and average rate, but they have little impact on the levels of maximum coverage and rate performance. Numerical results also reveal that better coverage and rate performance can be expected in scenarios with higher small cell path loss exponent.