Research On Resource Allocation Algorithm For Device-to-Device Communications In Cellular Networks

With the development of social economy and communication technology,it has become a way of life for people to obtain data and digital services anytime and anywhere through the network.Application demands and technology interact like forces and reactions,leading to fierce competition among wireless communication network against the explosion of data flow,access of massive users,and continuously emerging of new services.Device-to-device(D2D)communications,one of the key technologies of the 5th generation mobile communication network(5G),has been a matter of great concern.D2 D allows the adjacent devices in the network to communicate directly,reusing precious spectrum resources with the advantages of short distance and low power,effectively relieves the data pressure of the core network,and opens up a new way for the user access and data transmission of large-scale super dense network.D2D communications for cellular networks can bring considerable benefits with scarce spectrum resources by flexible access and multiplexing modes with the assistance of base station.In line with its inherent advantages,D2 D triggers complicated competition and interference.Numerous technical difficulties are to be worked out,while designing a reasonable resource allocation scheme to effectively coordinate interference is the focus of D2 D communications research.It is vital to improve the performance systematically through the transition from one-to-one to one-to-multi mode,as well as the evolutionary shift from uni-cast to multi-cast.However,D2 D communications in cellular network has given rise to the emergence of multi-layer interference links,differential rate requirements,and the fusion of social and physical characteristics,resulting in more complicated optimization problem of D2 D resource allocation.In view of the above problems,this paper makes an in-depth study and puts forward some innovative methods.(1)In the one to many reusing mode between D2 D pairs and cellular users,the overall optimized resource allocation algorithm tends to share the cellular resources with a certain number of D2 D pairs with channel advantages in non-uniform distribution scenarios,but the quota restriction is contrary to the differentiated service requirements of D2 D pairs.The paper proposed a resource allocation algorithm for D2 D communications based on rate requirement to allocate resources at required rate through interference limited area and link stability sharing threshold.The simulation results indicate that the proposed algorithm gains higher system performance with fewer reduction of cellular user data rate,and ensures the system fairness of resource allocation.Compared to In GRA,the proposed algorithm brings a rise of 21.6% in system throughput.(2)To avoid redundant transmissions caused by adjacent users requesting for the same data content in cellular downlink communications,a novel social-aware resource allocation algorithm for multicast D2 D is proposed.The algorithm utilizes the influence of social relations on the potential communication willingness and link stability of users.D2 D social clusters are thereby formed to retrieve data and avoid redundant transmission as well.This resource allocation problem is formulated as a matching game,in which D2 D social clusters and resource blocks(RB)negotiate with each other rationally and exclusively on basis of social utility functions to obtain optimal matching.To solve the peer effect caused by interacting between the D2 D social clusters sharing the same RB,swap operation is defined to eliminate blocking pairs and achieve bilateral stability.Simulation results show that the proposed algorithm performs well in sum data rate and convergence with lower complexity.The proposed algorithm is an effective way to improve the ability of network traffic offloading.Compared to MWBM algorithm,the proposed algorithm brings a rise of 15.2% in system throughput.(3)In view of the complex interference between D2 D communications and cellular uplink communications,the resource allocation algorithm for D2 D communications of Stackelberg game based on price and the resource allocation algorithm for D2 D communications of Stackelberg game based on cumulative cost are proposed.The intra-layer interference price and the inter-layer interference price are introduced to decouple the Qo S constraints of the Stackelberg game for power control.The optimal solution of the game is obtained by the Backward Induction method in which gradient descent method and Amijo Rule method are adopted to find direction and step size to update the Lagrange multiplier.A utility function based on cumulative cost is designed to further improve the convergence of system.Simulation results show that the proposed algorithms perform well in convergence and overall system throughput.Compared to CCPA,the propsed algorithm RASG-price and RASG-cumulative bring rise of 25.9% and 20.4% in D2 D sum rate,providing a distributed solution with fast convergence and good expansibility for resource allocation.