Research On D2D Communication Resource Allocation Algorithm In Heterogeneous Cellular Network

In recent years,technologies such as the Internet of Things,autonomous driving,and telemedicine have developed rapidly.The number of mobile devices connected to wireless communication networks has increased exponentially,data traffic has exploded,and spectrum resources have become increasingly scarce.Faced with the huge challenges that the rapid increase in traffic and traffic poses to traditional wireless communications,Device To Device(D2D)communications,as a new type of wireless communications technology,was introduced into the fifth generation mobile communication network(5G)in the system.D2D communicates with the cellular in the same frequency band,which not only improves the spectrum utilization,but also increases the reachable rate of the joint system,becoming an important technology for 5G communication.However,while D2D communication improves system throughput,it also brings interference to traditional cellular communication,which has a certain impact on the quality of cellular communication.In order to effectively control the interference under the Heterogeneous Cellular Network(HCN)and further improve the system performance,the paper studies the uplink spectrum allocation and D2D transmit power control issues in HCN.The specific work is as follows:First,the power control problem of D2D communication under HCN is studied.HCN is mainly cellular communication,and D2D communication is a supplement.The two communication methods can be regarded as individuals with a competitive relationship.Therefore,this paper introduces the Stackelberg game in game theory to study the interaction between cellular communication and D2D communication.The Stackelberg game is used as a framework to model the power allocation problem of D2D communication,and a one-to-many game model is formed in which the base station acts as the leader and the D2D user acts as the follower.D2D communication adopts underlay mode to share cellular spectrum,which will bring cross-layer interference to cellular communication.When there are multiple D2D pairs in the same spectrum resource,intra-layer interference will also occur between D2D,so the utility function of game participants The establishment should consider the impact of cross-layer interference and intra-layer interference at the same time.The main goal is to increase the total energy efficiency of D2D as much as possible by controlling the D2D transmission power on the basis of ensuring the energy efficiency of cellular communication.Through the mathematical analysis of cross-layer interference and intra-layer interference,the functional relationship between the interference price coefficient and the D2D pair transmission power is established,which makes the establishment of the utility function more reasonable from the perspective of game theory.A joint optimization algorithm of distributed power control and interference price coefficient iteration based on Stackelberg game is proposed.Simulation results show that this algorithm can significantly improve the total energy efficiency of D2D pairs in the system.Secondly,the problem of resource allocation for non-orthogonal multiple access(NOMA)enhanced D2D is studied.Different from the traditional D2D pair in which one transmitter corresponds to one receiver in the above research,NOMA enhanced D2D communication focuses on the D2D group,which includes one D2D transmitter and multiple D2D receivers,so NOMA can be used at the transmitter.The principle of superposition coding transmits information to multiple D2D receivers,and the receiver uses serial interference cancellation(SIC)technology to demodulate the required information,which can further improve the system throughput.Generally speaking,the interference coordination in the D2D and cellular joint system is mainly realized through reasonable and effective resource allocation.Therefore,this paper studies the resource allocation problem of the two to maximize the D2D achievable rate.The specific method is to split the resource allocation problem into two independent sub-problems: channel allocation and power control.On the one hand,appropriate frequency band resources are allocated to the D2D group based on the Coalition game.On the other hand,given the result of channel allocation,in the power control stage,the D2D transmit power and the power allocation factor involved in NOMA are jointly optimized according to the feasible solution domain to maximize the D2D achievable rate in the entire network.The simulation results show that the algorithm proposed in this paper can effectively reduce the computational complexity while ensuring the performance of the system.