Research On Energy-Efficient D2D Assisted Relay Technology In Cellular Networks

Recently,with the proliferation of the number and variety of smart terminal devices and the emergence of high-bandwidth applications,the data traffic of mobile wireless communications has increased dramatically,placing a heavy burden on cellular networks.Due to the scarcity of spectrum resources,mobile communication networks will face more severe challenges in the future.In addition,the limited battery capacity of intelligent terminal equipment makes it an urgent problem to reduce energy consumption.In summary,how to relieve the burden of the cellular networks,reduce equipment energy consumption and improve resource utilization are all problems that need to be solved in the future mobile communications.D2D(Device-to-Device)communication technology enables users with close proximity to communicate directly without the forwarding of the base station,which has broad application prospects in relieving network burden,reducing equipment energy consumption and improving resource utilization.D2D assisted relay technology based on D2D communication can effectively improve network performance by utilizing users with better conditions as relays to assist the communication of other users.Therefore,it is of great research value.This thesis studies D2D assisted relay technology in cellular networks,aiming at relieving the burden of the cellular networks,reducing equipment energy consumption and improving resource utilization.Firstly,in the scenario of UE-to-Network Relay based on D2D assisted relay,to solve the problem of limited battery capacity of intelligent terminal devices,the low-energy device communication is studied and an energy-efficient D2D SL-DRX(Sidelink Discontinuous Reception)scheme is proposed.The scheme mainly deals with the case of SLDRX-InactivityTimer timeout.When the timeout occurs,the traffic volume is measured by the newly added PSCCH(Physical Sidelink Control Channel)counter.For the case of massive traffic,two kinds of SL-DRX cycle switching process schemes are proposed:1)Switching cycle according to the timer;2)Switching cycle according to the cycle switching control signaling of the SL-DRX.The simulation results show that the proposed scheme can reduce the energy consumption of the UE(User Equipment),increase the success probability of UE monitoring PSCCH and improve the throughput.Secondly,when multiple users are interested in the same content,the resource utilization can be further improved by combining the multicast technology.Therefore,the one-to-many transmission strategy based on D2D assisted relay is studied and an energy-efficient multi-hop clustering algorithm based on D2D assisted relay technology and multicast technology is proposed,including cluster head selection criteria and cluster member reassignment criteria.Different from the traditional clustering algorithm which only considers a single factor,our algorithm takes into account the data rate,the remaining power of the user and the end-to-end delay.The simulation results show that the proposed algorithm can reduce the end-to-end delay and improve the robustness of the system.