Research On Resource Allocation And Power Control Algorithm In LTE-Advanced Heterogeneous Networks

With the development of the Internet and wireless communication technologies, smart terminal devices are widely popular. The wireless mobile communication traffic will experience an explosive growth in the future. Traditional communication system will be unable to meet the demand for high speed multimedia data traffic. The most effective method to meet the challenge is to deploy a large numbers of Small Cells under the coverage of macro base stations, from which the networks’capacity will be greatly improved through the gain of cell splitting and spectral efficiency.The goal of this research is to improve the energy efficiency of the heterogeneous networks and mitigate the serious interference in the dense small cell networks. The main contents of the research are concluded as follows:(1) In order to mitigate the cross-tier interference and improve the energy efficiency of the heterogeneous networks, a power control algorithm based on the Game Theory is proposed in this research. Firstly, a utility function is proposed to model the relationship between the network energy efficiency and the SINR of the small cell UE. Then the differential evolution algorithm is used to search the optimal solution of the utility function. Finally, a partial power reduction time domain scheduling scheme is proposed to allocate the resources reasonably. System level simulation results show that the proposed algorithm can not only optimize the network energy efficiency but also improve the SINR of the Small Cell UE.(2) The co-tier interference between the dense deployed small cells has become the most serious problem in the dense small cell networks. In order solve the problem, a coloring-based resources allocation algorithm is proposed. Firstly, we treat each small cell as a region on the map, then we use an interference matrix to quantify the inter-cell interference between the small cells. Secondly, we divide the small cells into some clusters based on the Graph Coloring Algorithm, we hold the point that there isn’t inter-cell interference between the small cells in the same cluster. Thirdly, a clustering based time-domain scheduling scheme is proposed, then we use the power control algorithm to set different transmission power for different small cells in different scheduling subframes. Finally, the system level simulation results show that the proposed algorithm can improve the network capacity and energy efficiency based on the traffic demand of the network.