QoS constraint optimal load balancing for Heterogeneous Ultra-dense Networks

With limited network capacity and dense development of wireless networks, Heterogeneous Ultra-dense Networks (H-UDN) is introduced to satisfy the demand of mobile users. But the traffic will be heavily unbalanced in the H-UDN. Thus, load balancing technique becomes a crucial problem. However, how to prevent the system resource from inefficiently using is also an important problem that needs to be considered during load balancing processes. In order to solve the above problems, we propose a Quality of Service (QoS) constraint optimal load balancing scheme to combine the load balancing with system resource utilization rate improvement. Firstly, We model the H-UDN as a Cournot game model with constrains of user QoS. Then, we deduce the optimal Load Condition Factor and the optimal resource allocated to each user through Cournot game model with genetic algorithm solution, the optimal Load Condition Factor is the resource utilization rate of each cell. Furthermore, based on the optimal Load condition Factor derived in the previous steps, we construct a bipartite graph to model the relationship between users and cells. At the same time, in order to realize the improvement of system resource utilization rate, the Kuhn-Munkres (KM) algorithm is implemented with optimal matching results for load balancing processes. System simulation results prove that the proposed scheme not only balances the load in H-UDN, but also improves the system performances of resource utilization rate, throughput and outage probability.