The Key Technologies Research On Intelligent Control And Optimization In Heterogeneous Networks

Currently a key issue in the mobile communications lies in the contradiction between the limited spectrum resources and explosively increasing demand of multimedia service. But there are some inherent limitations of traditional communications systems in space and time, which make the utilization of existing spectrum resources still not high. To improve the system capcacity, the development of communication systems in the future shows a heterogeneous trend that prompts the potential for spectrum efficiency as much as possible in terms of time and space, which includes the following three aspects:firstly, heterogeneous networks of different coverage. Secondly, the heterogeneous networks of different use priorities of wireless resources. Thirdly, the heterogeneous networks of different technical standards. These three kinds of heterogeneous networks could improve the performance of the communication system and alleviate the contradictions between the growth in communication service and spectram source scarce, but they also bring some technical chanllenges, the most important one of which is how to effectively control and optimize the heterogeneous networks. In spite of different forms of heterogeneous networks, they all have the same key objective to improve the utilization of spectrum resources, and have many things in common in relationship between different levels of network, optimization requirements and the methods used. They have similar characteristics of multiple network types, complex structure, diversification of performance targets and large number of parameters to be adjusted, so the traditional manual-based network planning, design, management and maintenance can no longer well meet the network operation requirements. It is needed to study smart and efficient wireless network design, management and optimization method for heterogeneous networks of new features, which can combine with communication theories and mathematical methods to achieve efficient control and utilization of network resources, elimination of interference between networks, effective collaboration of network elements, and so on.To deal with the problems in controlling and optimizing of the heterogeneous networks and achieve the goal of further enhancing spectral efficiency, this thesis studies a variety of key technologies of intelligent control and optimization in the heterogeneous network to use spectral more effectively and improve network capacity. The first chapter of the thesis describes the problems faced by the wireless communication system and the development trend of isomerization, then elaborates the background of the heterogeneous network, the basic concepts and the status quo, and derived the focuses of this study that researching on key technologies of intelligent control and optimization, in order to implement effective operation and maintenance at heterogeneous networks, and improve utilization of spectrum resources and network capacity. The main innovations of this thesis are as follows:Firstly, we describe the two-tier heterogeneous networks’problems and the status quo, then starts the researching from three aspects:efficient allocation of resources of the two-tier network, the intelligent optimization of network parameters and new technologies to enhance network performance. Based on cognitive technologies, heuristic algorithms and neural network, we proposed a series of intelligent control and optimization methods such as the two-tier network spectrum allocation strategy, channel and power allocation method, the antenna optimization technology, joint optimization technique of the wireless parameters, coordinated multi-point transmission technology, energy-saving methods and control system model. The simulation results show that the above methods improve the performance of the overlay network from the allocation of resources, interference cancellation, capacity maximization and so on, resulting in improving the radio resource utilization, reducing the interference of the network and effectively enhancing the capacity of the network.Then we study the control and optimization methods of resources’ use priorities based heterogeneous network and technology standard based heterogeneous network. After review of the background and research of these two heterogeneous networks, we focus on primary and secondary user network, in two typical scenarios propose approaches maximizing the overall network capacity through the secondary users’ channel and power allocation and on premise of ensuring the quality of the primary users’service. Then we study the method of users choosing the most appropriate network to access in accordance with the characteristics of the different networks and their own needs for multi-standard networks, which allows users to get a better quality of service (QoS), and ensures the overall network performance. In particular, we think low energy consumption as an important consideration, in order to as much as possible realize the green network communication.