Research And Design Of Transmission Scheme For Vehicle Communication Network Assisted By Intelligent Reflecting Surface

Vehicle communication network technology enables efficient communication and information exchange between vehicles and infrastructure,thereby improving road safety,traffic efficiency,and user experience.However,considering the complex propagation environment in modern cities,especially the obstruction from buildings in urban areas and the impact of high-speed vehicle movement,the vehicle communication link easily deteriorates,greatly affecting the performance of the vehicle communication network.To obtain a more reliable communication link,an effective auxiliary method for the vehicle communication network can be achieved by introducing Intelligent Reflecting Surfaces(IRS).This article studies the transmission scheme of IRS-assisted vehicle communication networks,including the following main aspects:For Vehicle-to-Infrastructure(V2I)communication scenarios in the vehicle communication network,under the constraints of IRS reflection coefficients and base station transmission power,the multi-user sum-rate optimization problem in the IRS-assisted vehicle communication network is studied.A transmission optimization scheme based on statistical channel state information is proposed.First,the statistical channel state information is utilized to establish a system optimization model to solve the problem of accurate acquisition of instantaneous channel state information during rapid vehicle movement.Then,the optimization model is transformed into subproblems that are easy to handle through fractional programming.Finally,an alternating iterative algorithm based on block coordinate descent is employed to achieve joint optimization of base station beamforming and intelligent reflecting surface passive beamforming.Simulation results demonstrate that the proposed scheme significantly improves the sum-rate of the vehicle communication network.For scenarios where both V2I and Vehicle-to-Vehicle(V2V)communications coexist in the vehicle communication network,a transmission scheme is proposed to maximize the V2I communication user sum-rate while ensuring the service quality of V2 V communication users and the limited transmission power of V2I base stations.The scheme utilizes an alternating optimization approach based on successive refinement and an improved binary search method to jointly optimize active beamforming at the base station and passive beamforming at the intelligent reflecting surface.Simulation results show that the proposed scheme improves the performance of the vehicle communication network while satisfying the constraints.