Research On Timeliness Of Two-way Data Exchange Systems Under The Age Of Information Measure

With the rapid development of Internet of Things technology,communication applications for real-time information transmission are increasing.In these applications,only the fresh and timely data has the highest application value.For example,in automatic driving applications,cars need to share their location,direction and speed information with neighboring vehicles in a timely manner.In environmental detection applications,timely access to environmental temperature,humidity,and harmful gas information is the key to ensuring the safety of human life and property.The age of information(AoI)theory provides a method to quantify the freshness of information and the theoretical basis for improving real-time network performance.Bidirectional data exchange technology based on energy harvesting and energy transmission is an important support for environmental detection applications.The method of simultaneously transmitting energy and instructions to the sensor through the access point of the observation center can achieve a sustainable and low-cost environmental monitoring task.However,under the condition of limited system energy,the timeliness and effectiveness of bidirectional transmission between the access point of the observation center and the sensor are also very limited,and it is difficult to achieve the best at the same time.To this end,this paper takes the relay-based unidirectional data transmission system as an entry point,deeply studies the timeliness and validity limits of the system's upstream and downstream data transmission,and designs a weighted optimal transmission mechanism.Specifically,the thesis includes the following aspects of work:1.Model the one-way data transmission system,through the analysis of the sample path of the information age and the average information age,construct the corresponding auxiliary function for the correlation between the waiting time and the arrival interval of the data packet,and take this Derive a closed-form expression of the system time of the directly connected link and the average age of information.Then through the analysis of the queuing model of the relay link,the distribution of relay link waiting and system time is derived.Use the auxiliary function to derive the closed expression of the average age of the relay link,and finally analyze the impact of the relay node on the system timeliness through simulation.2.Model the two-way data exchange system,derive the closed-form expressions of the average downlink information age and data rate,study the characteristics of the uplink energy collection process and service process,and derive the average uplink information age and Closed expression of data rate.3.Analyze the weighted average information age and data rate of the system from the two aspects of power distribution coefficient and weight coefficient to find the best average information age and data rate of the system.4.Verify the theoretical results obtained by simulation,and analyze the specific schemes to optimize the average age and data rate of the system from the aspects of power distribution coefficient and weight coefficient,and compare the performance of the power division system and the time division system from the aspects of timeliness and transmission rate difference.