Resourch On The Application Of D2D Communication Technology In Emergency Communication

The day of the 21st century is an information society, over the past 20 years, the development of mobile communication technology called explosive development, with us from 2G into the 3G,and then to today's 4G. Nowadays, many people is studying the 5G technology, in the near future it will enter our lives. However, in the field of public safety communication, the development of mobile communication technology is relatively lagging behind, today the 4G technology has been popular,public safety communication is still using 2G technology. Fortunately,the 3GPP (3rd Generation Partner Project) has considered emergency communications into its next work and has designated Device-to-Device(D2D) as the standard technology.In this paper, firstly we make an overview of the D2D technology and emergency communication technology, tell the development of D2D and emergency communication status. As the D2D technology is based on the LTE, we study on the LTE time-frequency resource and LTE resource management technology, thus laying the foundation for future research. Then, the research status of device direct connect technology is introduced, and the advantages and disadvantages of existing direct connect technologies such as Wi-Fi Direct and Bluetooth are analyzed.Then, the application of D2D in emergency communication scenario is studied. Firstly, we study on the resource allocation algorithm in D2D discovery phase, proposed an adaptive resource allocation algorithm based on the number of user in real scene. According to whether the wireless resources are sufficient, the algorithm adopts different resource allocation scheme to ensure that users can efficiently discover devices in different real scenes. After that, this paper presents a D2D-based emergency communication network construction program,using centralized resource allocation program to management. The proposed scheme enables the UEs to form clusters by using broadcast-based information exchange, and to mediate the medium access in the cluster or between clusters to communicate with each other by cluster head. Through the proposed scheme, UEs can communicate with UEs belong to the same cluster or the other cluster.The research of this paper has great practical significance. The proposed algorithm is simulated by self-built D2D simulation platform.The adaptive resource allocation algorithm based on the number of users in the real scene can dynamically adjust the resource allocation scheme according to the number of users, and effectively increase the speed and quantity of the device discovery. D2D-based centralized management of emergency communications network can quickly and effectively cover all users within the region. In the scenes with large number of users,through the avoidance of resource competition, can effectively reduce the transmission delay.