Research On Interference Coordination In LTE-A Heterogeneous Networks

With the rapid development of the internet technologies and wireless communication technologies, smart terminal devices have been widely spread, and thus lead to a large number of new businesses, most of which are multimedia data services. This trend makes a large growth of people’s demand for mobile data services. The future of wireless mobile communication will be faced with the challenge of growth of mobile traffic. An effective way to meet this challenge is to deploy low-power Small Cells under the coverage of conventional macro base stations (MBSs), so that the layer of MBS and Small Cell can coexist with each other to consist a heterogeneous network, by which the rapid growth of data traffic demand can be satisfied via the cell splitting gain and the closer distance between the base station and the user.Sponsored by the Fundamental Research Funds for the Central Universities:"Interference management technology of Small Cell based on LTE-Advanced"(Grant No.2013RC0111); the foundation from China Information Technology Consulting Institute:"Coverage enhancement technology research of LTE", the technology of interference coordination in LTE-A heterogeneous networks with Small Cell deployed has been deeply researched in this paper. Its whole system and key technologies have been introduced, and then previous interference management technologies, especially the interference coordination technologies, are summarized. In order to assign radio resource more reasonable in heterogeneous networks, a user partitioning based resource allocation and interference coordination method and a joint resource allocation and power control algorithm are introduced in this paper to solve the interference mitigation and coverage optimization. The main contents and achivements of the research are summarized as follows:The purpose of the user partitioning based resource allocation and interference coordination method is to mitigate inter-layer interference. The scheduler groups all the user equipments (UEs) into several sets according to the certain rule and then combines the frequency partition and power reduction to achieve interference mitigation, which promotes the cell edge users’SINR and system throughput at the cost of the performance of some cell center users. Simulation results show that the algorithm enhances system performance in terms of both cell edge users’ SINR and system capacity.The purpose of the joint resource allocation and power control algorithm is to protect cell edge users and enhance system capacity. Firstly, users choose their serving base stations based on the downlink received signal strength and cell range expansion bias. Then all users are parted into two sets and an adaptive resource assignment rule is used. Finally, the utility function combining throughput and interference is calculated by differential evolution algorithm. Simulation results show that the algorithm could protect cell edge users, bring better load blance and improve total system capacity.