Cooperative D2D Communications Based On Spatial Poisson Point Process And Social Network

With the continuous development of the mobile communication technology, mobile communication is committed to provide users with high speed, low energy consumption, low latency, personalized and many other novel services. D2D (Device-to-Device) communication as a new mobile communication technology can not only reduce the terminal transmitting power, increase the spectrum efficiency of cellular communication system, but can also solve the problem of the spectrum resource scarcity in the wireless communication system. D2D communication system has a brilliant prospects in the future communication system. Cooperative communication in the D2D technology has always been a hot research topic. Many existing researches have put forward a lot of D2D cooperative communication algorithms, but few of them consider the social relations among users. Though there are a lot of idle users can provide cooperative communications in reality, unfamiliar users may not join the collaboration due to security, residual power, the willingness of cooperation and many other reasons, which will lead to the failure of D2D cooperative communication. Therefore, it is a promising research direction to apply the social relations in D2D communication to encourage more users to participate in the collaboration, which is also the focus of this article.This paper first introduce the background and significance of the research, D2D communication technology, the Spatial Poisson Point Process (SPPP), the basic knowledge of cooperative communication and social network. Then the performance analysis of D2D cooperative communication based on the SPPP is discussed. According to the properties of SPPP, closed-form expression of the performance index of D2D cooperative communication is derived by assuming that the users are subject to SPPP distribution. It can be found that the user distribution density and the communication distance are important factors which affect the D2D cooperative communication. This article assumes the base station can determine whether the D2D transmitter has a social relationship with the surrounding idle users in a particular way. A new algorithm is proposed to calculate the strength of social relationships and base station records and manages the social relationships between the users through this algorithm. In order to further study the role of social networks in wireless communication, this paper designed a system model based on the social networks. Under this system model, three different relay selection algorithms are designed and the performance of D2D cooperativecommunication system based on social network are studied, as well as the advantages and disadvantages of the three relay selection algorithms. In cooperative communication, another important factor is how to motivate users to participate in the cooperative communication. As the social relationship between strangers is weak, some additional incentive is need to award to encourage the strangers participating in cooperative communication. So it is very important to propose a proper incentive mechanism. Further this paper applies the theory of contract from economics in wireless communication. As a kind of incentive strategy, the contract theory can improve the performance of system under condition of ensuring the interests of both managers and agents. The contribution of this paper is to take the social relationship into D2D cooperative communication and to study the important role of social relationship in wireless cooperative communication by designing different relay selection algorithms and incentive mechanism.