Research Of Small Cell Interference Suppression In LTE-A System

The introduction of small cell in the construction of 4G networks can effectively solve problems such as blind spots and insufficient capacity of network coverage,improve system performance,and bring better service experience to users.However,at the same time,the network coverage will be reduced due to the interference.Therefore,it is very important to study the interference suppression problem of small cell.The main work of the thesis is as follows:Firstly,a cluster-based resource allocation scheme is proposed to solve the cochannel interference problem in the dual-layer Macrocell-Femtocell network.The algorithm is mainly divided into three steps: Firstly,by using the fractional frequency reuse technology to solve the same layer interference of macrocells;Secondly,establish a clustering optimization model,the femtocell can be assigned to the different clusters so as to suppress the common-level interference between them,at the same time reduce the complexity of resource allocation;Thirdly,perform subchannel and power allocation according to the clustering results,and maximize the total system transmission rate while ensuring user fairness.The simulation results show that the proposed algorithm can significantly improve the user's SINR and throughput performance,while enabling users to obtain higher satisfaction.Secondly,a scheme to combine CoMP and resource allocation is proposed for Macrocell-Picocell scenario.The algorithm is mainly divided into two steps: 1.Clustering according to the reference signal received power(RSRP),picocells with strong interference are divided into the same cluster.The picocells cooperating in the same cluster,and provide services for edge users or users with poor channel quality.2.On the basis of adopting CoMP technology,aiming at improving the total transmission rate of the system,a target optimization function combining spectrum allocation and power control is established.To deal with the formulated resource allocation problem,we proposed a heuristic subcarrier allocation algorithm and power allocation algorithm based on Newton iteration method.The simulation results show that the proposed algorithm can effectively suppress the interference problem in the dual-layer network and improve the system throughput.Finally,through the field tests,the thesis focuses on the improvement of the coverage of the network coverage by the small cell and its possible impact,and proposes corresponding solutions to this problem.The test results show that deploying a small cell in a macro-cellular network can effectively improve the performance of the entire network.However,in a local area,the coverage performance index is reduced due to interference and other factors,but effective interference suppression technology can solve the network the co-channel interference problem,to ensure user service quality and overall network performance.