Research On The Social-aware Data Dissemination Mechanism In D2D Communication

In order to alleviate the contradiction between users' increasing traffic demand and limited spectrum resources,the 5th Generation Mobile Networks(5G)incorporates a variety of wireless access technologies that can improve the utilization of space frequency,and realizes the flexibility,speed and reliability of device access.Device-to-device(D2D)communication technology,as one of 5G wireless communication technologies,can not only realize spatial multiplexing of cellular spectrum resources but also realize direct communication between devices.With the increasing storage and computing capabilities of smart devices,D2 D distribution technology with D2 D communication advantages makes it easier to offload part of the base station's traffic to the user side.This thesis focuses on the research of D2 D data distribution mechanism,and the main work is as follows:Firstly,considering that users' social attributes and transmission energy consumption have an influence on the relay willingness of D2 D devices and the transmission quality of D2 D relay distribution,this thesis proposes a social trust-aware relay selection mechanism.This mechanism uses the acceptable energy consumption value of the relay node to select the duplex mode of each candidate relay node at the physical layer,and then proposes a social trust degree to measure the social attributes of relay nodes considering that the social attributes of relay nodes can have an influence on the stability of relay communication.Through the comprehensive measurement of the physical layer and social trust,the transmission performance of each relay node can be obtained.Finally,in order to improve the spectrum utilization rate of the system as much as possible,this thesis proposes a relay node selection algorithm based on the compromise factor combined with the importance of the data type transmitted by the source node and the transmission performance of the relay node.Simulation results show that the relay selection mechanism in this thesis has greatly improved the transmission rate and transmission reliability compared with the traditional D2 D relay communication mechanism.Secondly,due to the factors such as the user's limited storage space,personalized requests,and selfishness can affect the user's willingness to place different content,which in turn affects the overall effectiveness of the cache-based D2 D distribution method,this thesis proposes a D2 D collaborative caching strategy based on user needs which adopt the user's willingness to share as the main collaboration criterion.The strategy first personally models the user's request probability,and builds a collaborative group based on the user's request similarity to achieve the co-location of content.Next,considering that the difference in transmission load between users have an influence on the willingness to share within the collaborative group,a probability energy consumption threshold is set to limit the user's maximum transmission load.Finally,taking the probability energy consumption threshold as the limiting condition,this thesis combines social rate and file revenue to complete the placement of the content.The simulation results show that the cooperative caching strategy proposed in this thesis can improve various performances of D2D caching system.