Research On Information Age Perception Based On Cache Assistance And UAV Relay Safe Transmission Technology

With the continuous development of communication technology and further enhancement of people's life needs,mobile Internet has gained tremendous development,and a large number of emerging communication scenarios and demands have emerged.On the one hand,improving performance indicators such as spectrum efficiency,energy efficiency,and throughput has been a fundamental research topic in the field of wireless communication.On the other hand,the rapid development of Io T and mobile Internet has brought an unprecedented amount of mobile terminals and communication data,and a large amount of sensitive information is disseminated through wireless networks,so how to design a secure and efficient transmission method can be an urgent problem to be solved.Benefiting from the performance improvement brought by the buffer-aided mechanism,this paper takes downlink data transmission as the basic research object and conducts an in-depth study on the age of information and UAV-assisted relay security transmission mechanism in downlink multi-access network scenarios,respectively,and proposes an efficient transmission scheme.Firstly,this paper establishes a long-term time-averaged Age-of-Information(Ao I)minimization problem in a downlink non-orthogonal multiple access network with two users by considering the throughput rate constraint,peak power and average power constraint,and the problem is transformed and decomposed and solved by the Lyapunov optimization framework.An efficient buffer-aided adaptive transmission scheme(ABTS)with Ao I awareness is proposed by combining channel state information,energy state information and buffer state information,and the improvement of the proposed scheme in Ao I performance is verified by comparing different schemes.Secondly,the paper investigates the single-source-UAV mobile relay-single-destination node secure transmission problem.The paper considers joint trajectory optimization and realtime mode selection to maximize the reachable secure throughput from the source to the destination node in the presence of eavesdroppers and proposes a security-aware adaptive transmission scheme.The analytical results of the paper show that the location of the ground eavesdropper has an impact on the optimal UAV flight trajectory in order to maximize the reachable secure rate in the buffer-aided UAV relay secure transmission system,and the paper analyzes and reveals the intrinsic impact mechanism in depth.The analysis results of the paper show that the optimized flight trajectory of the UAV always converges to the same flight trajectory in the end in order to maximize the achievable secure rate of the UAV by changing the initial departure position of the UAV with a fixed source node,destination node,and eavesdropping node positions.In addition,the analysis results of the paper show that the achievable secure rate of the relay network is positively correlated with the buffer queue size.The analysis of the paper shows that the buffer-aided mechanism can significantly save UAV flight energy for a fixed total flight energy consumption and a fixed total data transfer volume.Finally,the effect of the maximum UAV flight speed on the achievable safe rate is discussed.Finally,the paper investigates the secure transmission problem of single-source-UAV mobile relay-multi-destination nodes,extending the work in Chapter 3.After problem modeling,solving and simulation it is shown that the layout of ground nodes and UAV buffer capacity have significant effects on the flight trajectory in a multi-user scenario,and the intrinsic influence mechanism is elucidated based on the buffer data queue and transmission mode of each time slot.Meanwhile,the simulation results reveal that the average secure throughput of the relay network is positively correlated with the buffer queue size.By adjusting the power allocation factor ?,the trade-off between maximum throughput and user fairness for UAVs under different mission requirements is explored.Finally,the effects of different starting positions and changes in ground node positions on the UAV flight trajectory are also shown.In summary,this paper has conducts an in-depth study on the introduction of buffer-aided at wireless communication nodes,explored the impact of buffer-aided on the emerging communication metric information age,explored the role of buffer-aided on the secure transmission of UAV relay networks,and efficient Ao I-aware and security-aware transmission schemes are designed based on the analysis results,respectively.