Study On Technologies Of Cooperative Coverage In Wireless Network

With the rapid development of mobile communication technology, a sharp increase in the number of users, a variety of new business after another, the bandwidth demand for mobile data services exponentially increasing rapidly, therefore, under the control of the construction costs and the network structure is not completely change the premise of how to quickly improve the overall capacity of the mobile network, especially the rapid movement of the mobile terminal at the cell edge or the environment, become the urgent need to solve the difficulty.The cooperative communication technology, as an effective means to solve this problem, in recent years has been a hot area of mobile communications research. The main idea is:the wireless network part of the user, according to a specific algorithm to form a plurality of distributed antenna array consisting of single-antenna user, then the MIMO multiple antenna technology into limited user terminal, form a virtual MIMO network structure, in order to obtain spatial gain, improve overall system capacity. The wireless communications network for the coordinated coverage that made the study and explore cooperative communication technology.First, article describes the wireless communication system channel transmission characteristics of MIMO channel models do the research, analyzed the impact of signal transmission in space, by the white noise, large/small scale fading and other factors, and the MIMO channel model and system capacity for analysis and simulation comparison.Then, elaborated and three cooperative communication relay method (enlarge forward, decoding forward and selective) relaying protocol mode, and channel capacity analysis and comparison of their different forwarding protocols.Finally, the article gives three user collaborative program (single-source single-user, single-source multi-user and multi-source multi-user), respectively, described its system model and each user’s power allocation. Optimal relay selection algorithm based on improved algorithm and its proposed threshold relay selection algorithm. Simulation results show that: the algorithm can enhance the system capacity in different degree. Compared with the conventional MIMO, such collaborative virtual MIMO transmission scheme will be an unprecedented development in the future mobile communication systems.