Research On Design And Optimization Of Edge Cache System For The Integrated Satellite-5g Network

The era of intelligence is coming quietly,and vehicles are gradually developing towards networking.Connected vehicles realize efficient autonomous driving through collaborative environment perception,computational decision-making and control execution,which is the development trend of next-generation intelligent transportation systems.The core foundation of connected autonomous driving is the Internet of Vehicles with ultra-high data transmission rate,low latency and high reliability.Millimeter wave communication has the advantages of large bandwidth,small antenna size,and low latency,and is one of the most potential solutions for the Internet of Vehicles.The main problem of mm Wave car networking is how to track the best communication beam for vehicles with low complexity and low overhead.This paper focuses on the hierarchical beam tracking method in the millimeter-wave Internet of Vehicles scenario to achieve the optimal trade-off between beam tracking overhead and beam alignment rate.The main content is divided into the following two parts.This paper firstly proposes a hierarchical beam tracking method for mm Wave Internet of Vehicles based on location prediction.The method consists of three stages:1)position prediction under the influence of noise,using the endogenous positioning technology of the Internet of Vehicles to obtain the distance between the base station and the vehicle,and combining the traditional hierarchical beam tracking method to predict the potential position;2)the initial search level prediction,According to the predicted potential position,derive the angle deviation of the best communication beam at the next moment compared to the previous communication beam;3)The optimal initial search level and code word decision,based on the angle deviation,determine the initial search level and the corresponding beam numbers.The simulation results show that the proposed method has a similar beam alignment success rate to the traditional hierarchical beam tracking algorithm,but the overhead is significantly reduced.Secondly,this paper proposes an improved beam tracking method for mm Wave Internet of Vehicles based on beam offset to solve the problem of error propagation caused by the beam transition zone.The method compares the difference between the received signal powers of adjacent beams with a predefined optimal threshold.When the power difference is greater than the optimal threshold,the traditional hierarchical beam tracking method is directly used to determine the search interval for the next stage;otherwise,the The auxiliary beam pairing algorithm estimates the signal arrival/departure angle,and then appropriately offsets the layer beam.Repeat the above operations until the best beam pair is found.The simulation results show that,compared with the traditional hierarchical beam tracking method,the proposed method effectively improves the beam alignment accuracy.