Research On Mode Selection Algorithm In D2D Communication System

D2D(Device-to-Device)communication as a new type communication method allows mobile users to directly transmit data without the help of base station's forwarding.This not only greatly improves spectrum resource utilization,decreases base station's load and user's energy consumption,but also effectively reduces network delay.D2 D communication mainly confronts challenges of interference management,mode selection,resource allocation and quality of service.This thesis takes the heuristic D2 D communication mode selection and D2 D communication mode selection issue based on social aware as objects to study.First of all,this thesis takes D2 D user's SINR as the dimension to study D2 D communication's mode selection issue,and transfers the mode selection into optimization issue in the goal of maximum throughput of system.In order to lower down the algorithm complexity,this thesis proposes a heuristic algorithm,dividing the issue into two sub issues,mode selection issue and resource allocation issue.Supposing that the community channel state information has been obtained,this thesis studies mode selection issue and respectively gets the terms of D2 D user using shared mode,dedicated mode and cellular mode,and designs a resource allocation strategy for the dedicated mode.The simulation result shows the algorithm can effectively improve D2 D user's transmission rate.Secondly,this thesis proposes a mode selection strategy based on social aware.Besides the physical connection state,this thesis adds user's social relation into the investigation factor,measures relation closeness of user's friend relations,calculates the similarity among users through user preference,thus getting user's comprehensive utility by combining the physical connection with the social relation.According to the obtained physical connection quality and social relation intensity,in the goal of maximizing user's total utility,this thesis designs a random algorithm to conduct user pairing.The simulation result shows the mode selection based on social aware can effectively improve user's total utility.This thesis proves that adopting proper mode selection strategy in D2 D communication can effectively improve the throughput of system.This analysis result has important meaning on research in aspects of D2 D network's performance improvement,resource planning and network construction design.