User Centric Ultra Dense Network Interference Management Technology

With the continuous development of mobile Internet and the next generation of Internet of things, more and more existing business and emerging business of the fixed Internet are provided to the users through wireless mode, which brings forward higher requests on the user rate and the flux density achieved by mobile communication systems. As the most effective means to achieve these challenging indicators, Ultra Dense Network (UDN) is able to meet the growing needs of users and data services, providing strong business support capabilities for mobile Internet and the next generation of Internet of things. Network architecture, business scenarios and requirements become more complex with UDN mode introduced into the 5G and next generation of other cellular mobile communication networks, which causes serious interference problems, bringing serious challenges to the management and control of the interference in the network.Based on the idea of user-centered design which adapts well to UDN,this thesis puts forward the interference management and control scheme which is under the constraint of limited information interaction, to meet the challenges above. Under the condition that the interaction of the interference information is not sufficient, the scheme realizes the effective interference management and control of the UDN by the cognitive algorithm which adapts to users' locations and users'communication environments.The main research contents and innovations of this thesis are as follows:1. The interference management and control of traditional cellular networks:The interference management and control of the traditional cellular network is studied through the typical traditional cellular network,OFDMA (Orthogonal Frequency Division Multiple Access) network. The closed-form solution of throughput and energy efficiency (the energy efficiency measurement was first proposed by the author and has been recognized by the authority) of the cellular network is derived to measure the effectiveness of interference management and control methods. FFR(Fractional Frequency Reuse) and SFR (Soft Frequency Reuse) are included in the schemes studied by this thesis.2. Algorithm of user-centered dynamic coloring interference management and control:Different from the traditional interference management scheme which allocates resources among base stations first, and then carries user scheduling within cells, the algorithm proposed in this thesis establishes directly a cognitive matrix to reflect the interference environments users experience. On this basis, the users' potential conflict graph is formed according to the strong interference threshold. Next, with the guidance of the idea of dynamic coloring, the strong interferences between users in different cells and the interferences between users within cells are avoided by coloring algorithm, effectively solving the network's ICI(inter channel interference) problem. Simulation results show that the proposed algorithm brings a higher total system throughput and edge throughput than the traditional one.3. Algorithm of user-centered environmental cognitive interference management and control:The algorithm is aimed to solve the selection problem of strong interference threshold faced by "Algorithm of user-centered dynamic coloring interference management and control" to enhance the algorithm's ability of adapting to complex network environments."Algorithm of user-centered dynamic coloring interference management and control" lacks of cognition of interference environment, resulting in the strong interference threshold selected adapting to some network environment only. With the users, cognition information to the interference environment, the algorithm of this part analyzes the interference of each user and let users select the interferences needed to be avoided by themselves from their potential interferences. Finally, the algorithm implement the interference management and control of the UDN by coloring algorithm. Simulation results show that the proposed algorithm works better than the traditional algorithm and the "Algorithm of user-centered dynamic coloring interference management and control".