Radio Resource Management For The Small Cell Heterogeneous Nework

With the development of the mobile internet and the rapid growth of the intelligent terminals, the mobile data traffic is increasing explosively. To cope with this problem, the concept of small cell network (SCN) has been proposed by3GPP (The3rd Generation Partnership Project).The small cell scenario will be a heterogeneous network scenario with high density and high coverage. Conventional macro cells provide fundamental coverage and mobility tracking for the UEs while the small cells provide high data throughput and offloading benefits[1].The small cell heterogeneous networks especially that with the dense deplyment of the small cells in the hot spots will bring new challenges to the interference, load balancing and energy issues which may lead to the limit of the experience of the large data traffic for the user equipments (UEs). This thesis mainly focuses on the radio resource management (RRM) for the small cell heterogeneous network.Firstly, the offloading procedure from the macro cell layer to the small cell layer may cause the load and interference distribution more unsymmetrical. To solve this problem, we propose an interference and load restricted offloading algorithm. During the offloading procedure, the interference and load conditions among the small cells are considered in order to avoid to increase the interference and make the load to a worse condition. The algorithm can improve the system performance.Secondly, to achieve the higher energy efficiency and reduce the inter-cell interference we propose an energy efficiency and interference avoidance based dynamic power control scheme. The scheme can adjust the transmit power and on/off states of the small cells according to the load and interference distribution. By using the scheme, the inter-cell interference can be reduced and the energy efficiency can be increased.At last, to slove the load distribution problem in the small cell scenario we propose a Voronoi diagram based load balancing scheme. The scheme can adjust the coverage of the small cells after load shifting which can balance the load among the small cells, reduce the interference and improve the system performance.The three proposed strategies have been compared with the existing techniques by system simulation. The simulation results show that the proposed strategies have better performances than the existing techniques, and verify that the proposed strategies are better solutions to the relevent problems.