Research On Short Packet Based On Physical Layer Secure Transmission In IoT

To meet the stringent requirements for ultra-reliable and low-latency communication(URLLC)for Io T in the field of automated operations,short packet transmission has been introduced as a key feature.It uses a finite block-length code for data to meet the system’s requirements for transmission reliability and low latency.At the same time,in many scenarios where short packet transmissions can be used,such as the Internet of Vehicles and the Industrial Internet of Things,the security of the data content transmitted is of paramount importance.In the event of an information breach,this could result in serious damage to the company or individual,so security should be ensured during data transmission.However,most existing study in short packet transmission only considers joint optimization of block length and transmission power to reduce decoding errors,while ignoring the more risky issues related to transmission security.Based on the above background,this paper focuses on the physical layer security of short packet transmission in Io T,adding transmission relays or intelligent reflective surfaces to the base station and receiver only,thus improving the confidential communication capability of the system.The main work and contributions of this paper are as follows:Firstly,a study of wireless relay systems based on short packet transmission is investigated.When two receiving users are at different distances with respect to the base station,relay transmissions are used to improve the overall confidential throughput of the system.The objective of maximizing the confidential throughput of the system is achieved by jointly optimizing the transmit power and the finite coding block length.Given that the objective optimization formulation is a non-convex problem,it is difficult to solve it by convex optimization methods.In this paper,we propose an algorithm that limits the range of variables and then performs a linear search to find the optimal solution to the objective problem;through simulation of this scenario,we verify that relay transmission is more effective in improving the security throughput of the system compared to direct transmission.Secondly,a study of relay systems based on intelligent reflective surfaces is investigated.The use of smart reflective surfaces to maximize the confidential transmission rate of the system in multiple input and multiple outputs(MIMO)environments is investigated.The study improves the system secrecy transmission rate by jointly optimizing the beamforming vector passing through the smart reflecting surface and the phase matrix of the smart reflecting surface.A constrained asymptotic algorithm based on a semi-positive definite programming optimization objective formulation is proposed to find a sub-optimal solution to the objective formulation;the feasibility of the algorithm is demonstrated by verifying that the sub-optimal solution approximates the optimal solution of the optimization objective function through simulation experiments;further analysis of the experimental results with different parameters is also carried out.