Research On Interference Coordination In Dense Small Cell Networks

With the development of the internet technologies,the wireless mobile communication traffic will experience an explosive growth.In order to meet the challenge,the most effective method is to deploy a large numbers of Small Cells under the coverage of Macro Cell,from which the capacity will be greatly improved because of the spectral efficiency.Because the deployment of Small Cell is intensive and randomness,the co-tier interference and the cross-tier interference user experience are serious,so the interference coordination technology in dense Small Cell networks(SCNs)has become a focus research in the academia and industry.The technology of interference coordination in dense SCNs hasbeen deeply researched in this paper.The goal of this research is to improve CRE users throughput and mitigate the serious interference and improve the energy efficiency in the dense SCNs.The main contents of the research are concluded as follows:In order to mitigate the severe downlink co-tier interference and cross-tier interference Small Cell CRE user suffer in dense SCNs,we present a resource allocation-based scheme to mitigate interference CRE users suffer.Firstly,we divide the dense Small Cells into different clusters by the graph coloring algorithm.Then we coordinate frequency resource allocation among different clusters and Macro Cell,which can better reuse resource blocks.After that,Small Cells in some clusters reduce power to mitigate the co-tier interference.Meanwhile,in order to alleviate the cross-tier interference,a utility function combining interference and throughput is calculated to find the optimal transmission power of Macro Cell by differential evolution theory.Finally,simulation results demonstrate that the proposed scheme can significantly improve the CRE users throughput.The co-tier interference between the dense deployed Small Cells has become the most serious problem in the dense SCNs,and a large number of Small Cells will consume a lot of energy.In order solve the problem,a novel power control based power control scheme is proposed to save energy as well as to maintain the network throughput for dense SCNs.Specifically,Small Cells are divided into two groups according to both the load and the inter-cell interference levels between the dense Small Cells,and accordingly the transmission power of the Small Cell is reduced based on the proposed utility function which can mitigate the co-tier interference while guaranteeing the SCNs energy efficiency.The existence of the optimal solutions to the problem is discussed,then the differential evolution is applied to obtain the optimal transmission power.System level simulation results demonstrate that the proposed scheme can significantly improve the SCNs energy efficiency.