Research D2D Communication Synchronization And Real-Time Protection Mechanism Based GPP

With the rapid development of mobile communication, there is a huge limitation of communication to the base station as the center of a conventional cellular network system. The Device to Device (D2D) technology is a direct communication link between the mobile devices to transmit business in emerging technologies. D2D technology has the link distance is short, high channel quality and meet near the information sharing between business users and provide high-speed, low latency, low power transmission services. D2D introducing heterogeneous network in a cellular network, you can make the network structure allow the flexibility to expand and coverage blind spots. At the same time, you can reuse the cellular network resources to improve cell-edge communication quality, improve the user experience and system capacity.The paper main work and innovation are as follows:Firstly, this paper focuses on a study of D2D technology which based on LTE networks, analyze existing popular hybrid network architecture, for its advantages and disadvantages, proposed a "base station-assisted self-D2D communication system" network architecture solutions. In this network architecture program, discussed the synchronization of different scenarios, including cell synchronization and device synchronization.Secondly, the design and implementation of D2D device synchronization scheme in hybrid networks. In the LTE network, the device user cannot be found in the vicinity of other user devices and connect to communications. By introducing a D2D-Sync channel in hybrid network to complete the device synchronization. D2D-Sync channel is used to assist the user device searches for the nearby devices, and to perform mutual communication with two D2D blind UE obtained D2D communication synchronization, and the necessary relevant broadcast information (SyncInfo). Finally, the design and implementation of real-time protection mechanism based on the data discarded. Hybrid network synchronization search takes longer to complete, resulting in the accumulation of large amounts of data or in the D2D system abnormalities due to network or part of a system treated slowly deteriorate as a result of real-time system, the mechanism by which data can be discarded to make the system quickly returns to normal traffic. At the same time the system has retransmission mechanism, not as a result of which led to the loss of important data discard the information.