Research On D2D In 5G Key Technologies

AS a common scene for users’life, Mobile communication is developing the fifth generation of communications standards (5G), which is to improve the system spectrum efficiency and have greater transmission rate. Device-to-Device Communication (D2D) technology is one of the key technologies in 5G communication. D2D communication is a way in which terminal devices have direct communication without going through base stations. D2D communication reuses cellular communication resource. D2D technology can reduce base station loads, and improve the cellular communication system spectrum efficiency. D2D communication also can enhance cell edge users’spectrum efficiency, etc. At present, many D2D communication studies are based on rules of regular geometry, which are kinds of ideal situation. Therefore, this article makes use of the random geometry theory, introducing the spatial poisson point process distribution theory, in which locations distribution of base stations are assumed to be a poisson point process. Poisson distribution is applied in this paper. We consider a more realistic scenario in order to obtain the analysis that is more accord with actual situation.High frequency transmission is another key technology in 5g communication, which is able to get wider band since spectrum resource is rich on high spectrum band, and alleviate the current situation of shortage of band resources. Millimeter wave is a kind of high frequency transmission technology, in which the wavelength is shorter, and the millimeter wave antenna can be used in handheld terminals. In this article, the millimeter wave technology is applied in the D2D communication. This paper proposes a model that chooses millimeter wave mode or micro wave mode in a link based on the communication distance. The outage and average spectrum efficiency of the hybrid model are deduced and simulated by matlab. The simulation results show that the introduction of millimeter wave mixing with D2D communication reduces the system outage probability.Current and future mobile terminals have multiple wireless interfaces, which can provide high data rate and the ubiquitous connectivity. Although multiple wireless interfaces bring convenience to users, which also bring terminal energy consumption at the same time. Energy harvesting is a new way to power the terminal power consumption, which has been widely studied. This article build a model that idle D2Ds harvest energy from the base station and other users over a period of time, and then transmit as the cellular users relay model over the other period of time. This paper studies the idle D2Ds as cellular users relay in different locations, and reduces cell communication outage probability. In addition, this paper studies the relationship between transmission time ratio and the system performance, in which the sum of transmission time and energy time must be fixed, and the optimal transmission time ratio is obtained from the simulation results.