Small-cell deployment over existing heterogeneous networks

To meet the extra traffic demand of hot-spot (HS) users not expected in the original network planning, it is desirable to deploy new small cells on top of the existing heterogeneous network (HetNet) without replanning the overall network. It is proposed to maximise the minimum user throughput in a HetNet with unexpected recurring HSs by jointly optimising the number and locations of new small cells and user associations of all cells. A reduced-complexity iterative algorithm is devised to solve the joint optimisation problem. The simulation results show that the proposed iterative algorithm significantly outperforms the random deployment of new small cells and achieves performance very close to numerically solving the joint optimisation in terms of minimum user throughput and required number of new small cells, especially for a large number of unexpected HS users.