Radio resource management for D2D-based V2X communication

This thesis proposes effective and efficient resource management approaches to mitigate the interference issue for Device-to-Device (D2D) based Vehicle-to-Everything (V2X) communication while satisfying different application requirements of safety-related and non-safetyrelated V2X services. Firstly, we investigate the resource management problem of safety-related V2X communication.Considering different network load conditions, we propose a novel approach of joint power control and resource allocation mode selection to mitigate the co-channel interference of V2X networks. In order to meet the specific Quality of Service (QoS) related demands of safety-related V2X communication, we maximize the overall information value of V2X communication by considering both ProSe Per-Packet Priority (PPPP) and communication link quality of V2X messages while meeting the requirements of minimum signal-to-interference plus-noise ratio (SINR) and maximum transmit power limitation for both pedestrian use requipments (PUEs) and vehicular user equipments (VUEs). Secondly, we propose a novel joint power control and resource scheduling scheme to enhance both the network throughput and the users' fairness of underlay non-safety-related V2X 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 time slot T to improve both the system throughput and fairness over a period of time. Prior works mainly focus on one-to-one matching between VUEs and cellular user equipments (CUEs). In contrast, here we propose a new scheme in which each VUE is allowed to occupy resources of multiple CUEs while each CUE's resource can be reused by one VUE at most. This scheme can not only guarantee the QoS of CUEs but also can improve the system throughput of the V2X network dramatically. Considering the high mobility of vehicles, in each Transmission Time Interval (TTI), the imperfect channel state information (CSI) is taken into account to track the fast variations of the channel state caused by the Doppler effect. To reduce the signalling overhead of the network, we propose a low-complexity Lower Bound-based One-to-Many matching (LB-O2M) algorithm to maximize the sum ergodic capacity of all VUEs under the restrictions of maximum transmit power of VUEs and the QoS requirements of both CUEs and VUEs. Extensive simulation results have demonstrated that the proposed resource management approaches can significantly and effectively improve the overall system performance of D2D basedV2X communication in terms of road safety, system fairness and network throughput.