Radio Resource Management For V2X Communication

Vehicle-to-Everything(V2X)communication has attracted much attention from industry and academia due to its inherent capability to offer solutions that improve traffic safety and efficiency.The paradigm of V2 X communication is an important facilitator for the intelligent transportation system and the automated driving systems.V2 X communication enables vehicles to exchange information with any entity that may affect the vehicle,and vice versa.Safety-related V2 X information plays a critical role in improving road safety and in the prevention of road fatalities through the use of warning messages.V2 X communication requires stringent high reliability and low latency because of its safety-related services.Device-to-Device(D2D)communication communication as a proximity-based service(Pro Se)enables direct communication between two devices without the intervention of the Base Station,thereby providing low latency and high data rates.Accordingly,D2 D communication is the most promising technology for V2 X communication platforms.Underlay D2D-based V2 X communication can provide high reuse gains to the cellualr network by reusing cellular resources.However,it also results in severe co-channel interference in cellular network.By properly managing the resources,the co-channel interference can be effectively mitigated.However,due to the Doppler effect caused by the high mobility of vehicles and the various V2 X service requirements,the resource management of D2D-based V2 X communication becomes more complicated and intractable to handle than that of traditional D2 D communication.Hence,this thesis proposes effective and efficient resource management approaches to mitigate the interference issue for D2D-based V2 X communication with imperfect Channel State Information(CSI)while satisfying different V2 X service requirements in terms of the road safety,system capacity and users' fairness.Firstly,we investigate the mode selection problem of safety-related V2 X communication with imperfect CSI.Considering different network load conditions,we propose a novel approach of joint mode selection and resource allocation to mitigate the co-channel interference of V2 X networks.In order to meet the specific Quality of Service(Qo S)related demands of safety-related V2 X communication,we maximize the overall information value of V2 X communication by considering both Pro Se Per-Packet Priority(PPPP)and communication link quality of V2 X messages while meeting the requirements of minimum signal-to-interference-plus-noise ratio(SINR)and maximum transmit power limitation for both cellular user equipments(CUEs)and vehicular user equipments(VUEs).Extensive simulation results show that both the information value of VUEs as well as the spectral efficiency of PUEs can be improved efficiently by the proposed approach.Secondly,we investigate the joint power control and resource allocation problem for D2D-based V2 X communication in a more practical case where the CSI is imperfect.We aim at maximizing the sum ergodic capacity of all VUEs with imperfect CSI under the minimum SINR requirements of CUEs and the outage probability constraints of VUEs.Specifically,we derive an approximate closed-form expression of VUE's ergodic capacity based on Jensen's inequality and propose a simple and efficient Lower Bound-based power control approach to solve the power control problem with low computational complexity.Based on the optimal power allocation results,we further propose an one-to-many matching algorithm to solve the spectrum resource allocation problem,which is tailored to the scenario where the maximum number of reuse CUEs for each VUE is limited the maximum transmit power of the VUE.The numerical results verify the tightness of the proposed algorithm and demonstrate the proposed algorithm can enhance the sum ergodic capacity of VUEs efficiently and effectively.Thirdly,we propose a novel joint power control and resource scheduling scheme to enhance both the network capacity and the users' fairness of underlay V2 X communication network.Unlike other previous works in this area,our scheme aims at maximizing the sum of all users' proportional fairness functions while simultaneously taking into account factors such as fairness,SINR requirements and severe interference.The proposed algorithm takes into consideration time slots of long duration and is implemented in two stages: stage 1 realizes the initialization of the average data rates of all users by the proposed joint power control and resource allocation method;and stage 2 develops the proposed joint power control and proportional fair scheduling scheme from the second time slot to the current time slot to improve both the system capacity and fairness over a period of time.Numerical results confirm that our proposed scheme not only dramatically improves the system capacity but also boosts the users' fairness.