Research On Device-to-Device Based Content Distribution

With the continuous development of the Internet,the traditional cellular network can not meet the increasing demand of multimedia content.As a short-range communication technology with the characteristic of high communication quality and flexibility,Device-To-Device(D2D)communication allows users to communicate directly with each other.This technology is a vital solution of network congestion in current existing cellular network.With the ubiquity of wireless network and the intelligentization of machines,Internet of Things(IOT)has come to people's horizon.However,in order to connect a large number of intelligent devices to the network,traditional cellular networks become overwhelming,which exposes the problems of limited bandwidth,limited access capacity and uneven distribution of network nodes.Content distribution technology can provide users with high quality,high efficiency and distinct network order application services,it can alleviates the above mentioned problems.Device-to-Device(D2D),as one of the advanced technique to achieve the vision of IoT,supports a high speed peer-to-peer transmission without fixed infrastructure,which enables fast content distribution in local area.This paper firstly investigates the problem of multi-hop D2D.Considering the joint relay selection,spectrum allocation and power control optimization problem of two-hop D2D relay transmission in cellular networks,a price based four-dimensional matching algorithm is proposed to determine the D2D transmitter and matched D2D relay,spectrum and transmission power,so as to maximize the energy efficiency of the D2D links and ensure the quality of service of all communication links simultaneously.Then,the content distribution problem is solved by multihop D2D communication with decentralized content providers locating in the networks.A multi-dimension optimization involving frequency,space,and time is considered to minimize the network average delay.Considering the multicast feature,the problem is firstly formulated as a coalitional game,and then,a coalition formation based algorithm is proposed to spread the content within the shortest possible time.Simulation results show that the proposed approach can achieve a fast content distribution across the whole area,and the performance on network average delay is much better than other heuristic approaches.