Research On Offloading Methods Based On D2D Cooperative Communication

In recent years,the wireless standards organization has completed research on the fifth generation(5G)of broadband communication technology,which offers numerous advancements in wireless system design,resulting in significant improvements in spectral and energy efficiencies as well as user quality of service(QoS),etc.However,with the rapid growth of smart devices,it has led to explosive demand for mobile multimedia services.It is commonly believed that even 5G will not be able to accommodate unanticipated acceleration in traffic fueled by the rapid proliferation in varieties and numbers of wireless mobile devices.Device-to-device(D2D)communication is a promising technique for traffic offloading in next-generation cellular systems.In recent related research,resource reuse and interference mitigation have become important research parts in D2D-enabled cellular networks offloading.However,these studies did not analyzed in combination with special scenarios,which lead to the network resources not being fully utilized.This paper mainly proposes the data offloading using D2 D technology in two different cellular scenarios and provides two resource allocation schemes for data offloading.First of all,considering that the coverage of the micro base station is small,and the number of channel boards that can be installed is limited,and as the user's mobile data traffic has been explosively growing can cause the micro base station is overloaded and it is difficult to meet the user's demands.Due to the denser characteristics between users in this scenario,this paper uses D2 D technology to assist the micro base station to perform data offloading in dedicated mode and designs the offloading method from the perspective of economic and user interests.Taking into account user traffic demands and user's location,this paper formulates the problem as a “Min-Max” problem,in which the operator cost is minimized and meanwhile the user utility is maximized.The problem is proved to be a NP-complete problem and can be transformed into an approximate combinatorial optimization problem,then it can be solved by developing a backpack algorithm combined with a linear assignment algorithm.The simulation results show that the offloading scheme can satisfy both the interests of the cellular network operator and the users.Secondly,considering that the macro base station has a wide coverage,some “blind spot” with poor communication quality and some "hot spot" areas without infrastructure coverage are often generated under the macro base station,so this paper proposes a resource allocation scheme for D2 D communications and cellular users shared link spectrum in an overloaded macrocell base station.In order to encourage cellular users to participate in the offload,D2 D users need to pay the cellular users a certain price to compensate for the interference caused by them.This paper proposes a two-step resource management scheme,which first defines the interaction between cellular users and D2 D user pairs as the Stankelberg game,and then matches the users based on geographical restrictions.In this paper,the power optimization PWOA algorithm and the Hungarian-based UCMA algorithm are utilized to allocate the channel spectrum resources to maximize the system capacity.Finally,the simulation experiments of the data offloading schemes proposed in the above two scenarios are carried out respectively.The experimental results show that the proposed methods achieve better performance in terms of offloading efficiency,system capacity,energy consumption and user utility.