Research On Wireless Resource Allocation And Data Dissemination Strategy For D2D Hybrid Network

As the popularity of intelligent communication terminal and the development of wireless communication technology,wireless multimedia services and new applications has shown explosive growth trends.Some proximity-based applications,such as peer to peer data sharing,location aware information transporting,local multicasting and advertisting,and so on,have become the primary means of access to information.In order to meet the increasing demands of new business service as well as to provide better user experience,device-to-device(D2D)communication technology have being considered as one of the key technologies in future wireless communication network.By introducing D2 D communication technology into the traditional cellular communication system,cellular users(CUs)and D2 D users(DUs)can coexist in a heterogeneous network.D2 D communications establish direct communication between mobile nodes in-comparison to conventional cellular networks alongwith potential benefits,such as enhanced spectral efficiency,improved user experience,improved energy efficiency and extended cell coverage.Nevertheless,D2 D communication may cause serious interference on cellular network due to sharing cellular resources.In this dissertation,we study the radio resource optimization and data distribution with the focus on the enhancement of spectrum efficiency and energy efficiency,expecting to obtain D2 D communication schemes in which to reduce the interference between users and to exploit the potential performance gains,so as to provide a theoretical base for future research and some useful guidelines for investigating more complex data distribution systems.The major research works of this dissertation include the following parts:(1)The issue of the spectrum efficiency of the heterogeneous network optimization is studied in underlaying D2 D unicast hybrid network where multiple D2 D links reuse the uplink resources of CUs.Considering on the network valid gain,minimum required transmission rate for CUs,maxmum transmission power limit for D2 D pairs,etc.,we investigate the resource allocation strategy based on joint subband matching and power allocation.The strategy includes two parts.First,an subband matching method by employing a heuristic algorithm is proposed to assign subband for D2 D pairs.Then a power allocation algorithm based on the Lagrangian dual method is developed to determin the optimal transmission power on given subband.Numerical results show that the advantageous performance of our scheme in greatly increasing the system sum spectrum efficiency.(2)The uplink resource allocation issue is studied when D2 D multicast groups share the resources with other CUs while guaranteeing a certain level of quality of service(QoS)to CUs and D2 D users.We first address a flexible tradeoff framework in which the system power consumption and the system capacity(i.e.,the number of admitted D2 D links)are assigned with different weight factors so that these two objectives are jointly considered.Then we propose an efficient resource optimization scheme which comprises sub-channel allocation and signal-to-interferenceplus-noise ratio(SINR)assignment.Numerical results validate the effectiveness of the proposed framework,and demonstrate the advantages in dealing with the proposed multi-objective optimization problem.(3)The issue of D2 D multicast throughput optimization is investigated in D2 D communications overlaying cellular network.In order to fully explore the diversity of the D2 D relay channel capacity,we analyze the relationship between the D2 D throughput and the number of D2 D relay,formulate the objective function of optimization problem.Then,we introduce an iterative combinatorial auction algorithm for efficient D2 D relay selection.In combinatorial auctions,the User Equipments(UEs)that fails to correctly receive multicast data from the evolved Node B(eNB)are viewed as bidders that compete for D2 D relays,while the eNB is treated as the auctioneer.We also give properties of convergency and low-complexity and present numerical simulations to verify the efficiency of the proposed algorithm.(4)The issue of cooperative energy-efficient content dissemination among a number of cellular UEs is investigated in outband D2 D heterogeneous network,with the assumption that these UEs are seeking to receive the same content from a common wireless access point such as an eNB.We formulate the problem as a non-transferable utility coalition formation game,in which a utility function is characterized by taking into consideration energy efficiency and mutual interference in the scenario of proximity D2 D communications.Then,we develop a distributed coalition formation algorithm.With the proposed algorithm,UEs that are in proximity of each other can cooperate and then self-organize into independent disjoint coalitions,and finally minimize overall network energy consumption by using D2 D communications.Simulation results show that using the proposed algorithm,significant energy savings can be achieved compared to the cellular multicasting case and the non-cooperative case,which validates the high energy efficiency of the proposed game theory based algorithm in wireless content dissemination scenarios.