| Recently,a new technology called device-to-device(D2D)communication,which enables direct communication between user equipments that are in proximity,has been proposed and has strongly appealed to both academia and industry.The adoption of D2 D communication in cellular networks holds the promise of many types of gains,for example allowing for high-rate low-delay low-power transmission for proximity services,tightening the frequency reuse factor and increasing the network capacity,extending the cellular coverage,etc.On the other hand,the adoption of D2 D communication brings into a number of technical challenges,and interference management becomes a major issue in D2D-enabled cellular networks,since the D2 D links share the same spectrum resource with the regular cellular links and the interference between the two types of links would severely hamper the performance of the network.This thesis focuses on the topic of interference management for D2D-enabled cellular networks,and three types of interference management techniques are studied.First,from the perspective of interference coordination,we study the spectrum sharing problem in D2D-enabled cellular networks,and employ two mechanisms to incentivize the cellular system to share spectrum with the D2 D link.The first is the cooperative relaying mechanism,in which the D2 D link is required to relay the transmission of the cellular system to guarantee a desired cellular data rate.We propose two superposition coding-based cooperative relaying schemes to exploit the transmission opportunities for the D2 D link without affecting the performance of the cellular system.The second is spectrum trading mechanism,in which the cellular system is allowed to charge the D2 D link a fee for spectrum usage to enhance its profit.We model the cooperative relaying-based spectrum trading process between the cellular system and the D2 D link by a principal-agent framework,and design the optimal power-payment contracts for the cellular system under both the cases that the private information of the D2 D link is continuous and discrete.Second,from the perspective of interference cancellation,we study the performance of interference cancellation techniques in large-scale D2D-enabled cellular networks using the tools from stochastic geometry.We first derive the successful transmission probabilities of cellular and D2 D links in the network without interference cancellation capabilities as the baseline results.Then,to simplify the interference analysis,we propose the approach of stochastic equivalence of the interference,through which the two-tier interference can be represented by an equivalent single-tier interference.Based on the proposed stochastic equivalence models,we derive the successful transmission probabilities of cellular and D2 D links in the networks where unconditional interference cancellation and successive interference cancellation are respectively applied.The effectiveness of these two interference cancellation techniques for improving the performance of D2D-enabled cellular networks is validated by both analytic and numerical results.Third,from the perspective of interference exploitation,we focus on a largescale D2D-enabled cellular network in which cellular communications are overheard by eavesdroppers,and propose a framework for modeling such a network via stochastic geometry.We derive the expressions for connection and secrecy probabilities of cellular and D2 D links,based on which we further design optimal D2 D link scheduling schemes under both strong and weak performance guarantee criteria for cellular communications.By investigating both analytical and numerical results,we find out that the interference from D2 D communications can be exploited to enhance physical layer security of cellular communications and at the same time create extra transmission opportunities for D2 D users.This study provides a new perspective on the role of the interference generated by D2 D communications. |
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