Research On The Optimization Technology Of Cooperative Communication Based On Complex Networks

The 21th century is a time of rapid development for information technology. As the demand of wireless communication bandwidth grows rapidly, wireless mobile communication technology for higher rate, wider bandwidth and higher frequency is needed. Cooperative communication transceiver antennas in relay nodes and cooperative communication are used to form a multi antenna array. Thus form a virtual MIMO system, so as to get the space diversity gain and improve the reliability of communication transmission. From a certain ideological, cooperative communication technology not only makes a compensation for the defects of the classic MIMO technology, but also brings a new idea for the practical application field of MIMO technology. With its unique design ideas, cooperative communication has prospect and far-reaching significance in the development of future wireless communication. For networks like cellular mobile communication network, wireless self-organizing network, wireless sensor network and vehicle network, it plays an important role. Because wireless communication network is a highly efficient solution for lower cost radio resource allocation, it will be an important technology for wireless communication framework in the future days. Complex network is a new subject developed in recent years, as an important theoretical tool for complex system, it mainly describes the network topology relationship between nodes and nodes, the characterization of nodes and system, so it becomes the basis of in-depth analysis for complex systems and help in finding the basic properties and rules of complex systems. As a theoretical research model widely exists in the nature world and our society, complex networks play a role in many disciplines. In computer science, wireless communication system, control theory, electronic circuit system, medical science, biological science, environmental science, social economics and so on, we can find its' application. Therefore, based on the knowledge of complex network theory, the main work of this paper is to study the existence of some key scientific issues in the cooperative communication network:(1) A new model of cooperative communication network evolution based on BA (Barabasi and Albert) model is proposed, and the evolution characteristics and evolution law of the network are analyzed. In the cooperative communication network, some nodes with better performance and higher communication capacity are easier to communicate with other nodes. Thus, in the process of network evolution of a new node or adding links to the network, the network of the existing node selection is very worth studying. The evolution of cooperative communication network is according to the following steps:Firstly, the increase of nodes; second, the increase of links; third, the decrease of nodes and finally, the decrease of links in network. By that, it establish a BA extensible model to analyze the characteristics of cooperative communication network evolution. At the end of this paper, numerical simulation is used to verify the performance and robustness of the network.(2) A hybrid cooperative communication network optimization model based on BA and ER (Erd?s and Rényi) is proposed. To avoid the indefinitely increase of old node degree caused by the saturation of network node communication capacity in evolution, but also to avoid the randomized selection of relay nodes in cooperative communication. The BA scale free network model has the characteristics of network growth and preferential connection. As the evolution goes on, the network is composed by a little high value nodes and a large number of low value nodes. In ER random network model, the link between two points has the same probability. With the same link number and network size order, a sparse graph has no clustering characteristics for fixed network density. The degree of nodes in network is close to the average value of network. Based on the above analysis, this paper establishes a cooperative communication network evolution model based on BA and ER. analyzes the characteristics of the network model and the robustness of the network model. Finally, numerical simulation is used to verify the performance and robustness of the network.(3) A hybrid adaptive cooperative communication network optimization model based on BA and ER can be well adapted in cooperative communication networks. New network nodes with some high communication performance can obtain more communication connection with a fitness value. Taking into account the difference between the nodes of the fitness model is based on the performance of each node to give a weight to each node, through the weight value to control the ability of the node to get links. This model can be applied to the cooperative communication network, and some new network nodes with high communication performance can get more communication links by giving a weight value to the network. Based on the fitness of the cooperative communication network evolution model, and the model of the network characteristics are analyzed, and then the network model for robustness analysis. Finally, numerical simulation is used to verify the performance and robustness of the network.(4) Based on a deterministic small world model of the cooperative communication network for relay node selection is proposed, cooperative communication network model can relatively uniform well applied in clustering and have obvious characteristics of small world. First of all. because of the random connectivity link in random model is not suitable for the communication network, which includes fixed node connectivity characteristics, so the establishment of cooperative communication network evolution model based on deterministic small world characteristics, and the network characteristics were analyzed. Then, the cooperative communication network based on small world model uncertainty, the relay node selection strategy with maximum degree and minimum clustering coefficient, adding boundary value parameters, analysis of the strategy in the cooperative communication network relay node selection effect, and compared with the maximum degree of relay node selection strategy and the minimum clustering coefficient of relay node selection strategy analysis. Finally, the performance of the simulation model is simulated and verified by the simulation model.