Mobile Small-cell Deployment Strategy for Hot Spot in Existing Heterogeneous Networks

As the mobile data demand keeps growing, an exist- ing heterogeneous network (HetNet) composed of macrocells and small cells may still face the problem of not being able to provide sufficient capacity for unexpected but reoccurring hot spots. In this paper, we propose a mobile small-cell deployment strategy that avoids replanning the overall network while fulfilling the hot spot demand by optimizing the deployment of additional mobile small cells on top of the existing HetNet. We formulate the problem as a joint optimization over the number and locations of mobile small cells and the user associations of all cells in order to maximize the minimum user throughput. In order to solve it, we first propose a Fixed Number Deployment Algorithm (FNDA) to solve the problem with a fixed number of new small cells. Afterwards, we extend FNDA into a Deployment Over Existing Network Algorithm (DOENA) to solve the joint optimization problem. The simulation results show that DOENA offers a higher minimum user throughput while requiring less mobile small cells to be deployed than the deployment optimization based on maximizing sum user throughput.