Joint optimization on load balancing and network load in 3GPP LTE multi-cell networks

In this paper, we jointly investigate load balancing and network load minimization in 3GPP LTE multi-cell networks. Load imbalance often causes inefficient utilization of system resource, which may result in a high new call blocking rate. However, switching users only for load balancing with no consideration of network load often results in aggressive handovers of users, which may occupy quantities of resources in target cells so as to increase the new call blocking rate and decrease the bandwidth efficiency of the network. Thus, our objective is to balance the load distribution among neighboring cells as much as possible, while to increase the network average load as little as possible. First we pose a multi-objective optimization problem, which objectives are load balancing index and average load of the network with constraints of physical resource limits and users' Quality-of-Service (QoS) demands. After that, we transform the problem to be a single aggregate objective function optimization problem, analyze its complexity and propose a practical algorithm which considers network load minimization with load balancing (NLMLB). Extensive simulations are conducted, and the results show that our algorithm leads to significantly better performances of a lower new call blocking rate, a fewer system resources occupation and a higher network bandwidth efficiency.