Resource Allocation For Heterogeneous Networks Based On D2D

In recent years,the number of mobile devices has grown dramatically,while the demand for video streaming services has increased.As a result,spectrum resources have become extremely scarce.As one of the key technologies of 5G,D2 D allows the direct communication links to be established within the terminal devices with similar physical locations,and makes it possible for D2 D users and cellular users to share spectrum resources.Therefore,D2 D communication is regarded as the most promising solution to improve system spectrum utilization and cellular network throughput.However,introducing D2 D communication technologies into traditional cellular networks will bring new challenges.This thesis has done in-depth research on two aspects of interference and energy efficiency in heterogeneous wireless networks consisting of cellular networks and D2 D networks.The specific work is as follows:1.Aiming at the interference problem of D2 D users and cellular shared spectrum resources,aiming at optimizing the throughput of D2 D links in the system as the optimization goal,a resource allocation mechanism for joint power control and channel allocation is proposed.Firstly,according to the interference threshold of D2 D users and the Signal to Interference plus Noise Ratio(SINR)of cellular users,a multiplexing criterion based on the distance between users is proposed to determine the set of channel resources that can be reused by D2 D users.Secondly,under the premise that a given D2 D user multiplexes any set of resources,the D2 D user's transmit power is adjusted to measure the throughput of each D2 D user on different channel resource sets,but power is not allocated temporarily.Finally,based on the result of power control,the combination is adopted.The auction method allocates channels and corresponding transmit power for the D2 D link,thereby implementing joint power control and channel allocation,so the system resource allocation result is more reasonable.The simulation results show that this mechanism can effectively suppress the cross-layer interference and the same-layer interference,improve the throughput of D2 D links,and improve the user's QoS(Quality of Service).2.Aiming at the problem of low energy efficiency of the mobile device and maximizing the energy efficiency of the user as the optimization goal,a resource allocation mechanism based on clustering is proposed.Firstly,D2 D users are clustered using graph theory and ant colony genetic algorithm.With the change of heterogeneous network scenarios,undirected graphs will change dynamically,thus forming a new clustering scheme.Therefore,the algorithm has adaptiveness;Secondly,using orthogonal cluster inter-cluster reuse as a criterion,using auction algorithms to allocate channel resources for D2 D users,can effectively reduce user-to-user interference;Finally,based on the selfishness of user behavior,the power allocation algorithm establishes a non-cooperative game theory model,and combines fixed-point theory and iterative algorithm to allocate power to the users who complete the channel allocation.As a result,the user's energy efficiency in the system is maximized.Simulation results show that this mechanism can effectively extend the battery life and improve the user's energy efficiency.