User Association in Heterogeneous Network with Dual Connectivity and Constrained Backhaul

A novel user association model for heterogeneous network(Het Net) with dual connectivity(DC) and constrained backhaul is proposed in this paper, where not only the best combination of serving macro cell and small cell for each user to associate is selected but also the optimal traffi c split between the macro cell and small cell is determined to enhance both radio resource effi ciency and backhaul capacity utilization. To solve this optimization problem, an intuitive algorithm based on iteratively solving two sub-problems is proposed. One sub-problem is a binary integer programming problem and a corresponding greedy algorithm is proposed, while the other sub-problem is a simple linear programming problem and can be easily solved. Numerical results show that the proposed model and algorithm can achieve better radio resource effi ciency and backhaul capacity utilization compared with user association in Het Net without DC, which validate the capacity enhancement potentials of radio resource coordination in Het Net with DC.