The Optiimization And Implementation Of Mode Selection Of D2D Communication Based On 5G

In the field of current communication and Internet, it's a trend of interconnection among all living things. However, the rapid increment of the amount of data result from varied demands of people has been out of step with the existing communication technology. In order to help users access network seamlessly and efficiently at anytime and anywhere, 5G system focuses on the 4G technology evolution and the emerging technology. Thus, the technique of D2D and its extension——V2X has become the hot topic since it came out. Facing the scenario of 5G at present, it will be of significance to reduce the traffic load of base station by assistive technology, and to improve the system's average throughput by reasonably allocating communication resources and switching communication mode.Aiming at D2D and cellular modes of mobile users, this thesis puts forward the scheme of switching communication mode. Based on the specified simulation method of 3GPP, inner cell and crossed cell mode,and the users' mobile management, this thesis takes dynamic simulation method on the condition of the users' relative distance and signal quality,and concludes the throughput gain of the average D2D users who take the mode selection scheme. The result shows that the scheme is effective in improving the throughput of system, which provides a reference for the mode selection in relative scenarios.Aiming at the characteristics of high speed mobility and high requirement of latency of V2X communication, this thesis comes up with the scheme of security information broadcasting and offloading on the road with the scenario of discrete LTE covering, and this scheme focuses on the non-vehicle density scenario. Aiming at the problem that insufficient vehicle for sustaining mesh topology and inefficient trassmission of information, this scheme realizes V2V indirectly by V2I.The scheme takes several small cases according to the information type and designs signaling procedure and resources deployment to specificly describe and reasonably analyze the project.Aiming at the DSRC-Cellular network structure based on the D2D-Based V2X, this thesis had surveyed the maintenance of topological structure and information interaction between dynamic and static node in the layered architecture. Aiming at the characteristics of high safety and low latency of DSRC, this thesis describes a clustered-node communication method which can dynamicly maintain the nodes in the cluster, and it's of importance for the cluster communication scenario in the future city.