Joint Backoff Algorithm Based on Information Freshness and NE Equilibrium in Low-Earth Orbit Satellite IoT Scenarios

The average Peak Age of Information (PAoI) and the average Age of Information (AoI) are crucial for control policies in the Satellite Internet of Things (S-IoT) observation environment. However, most existing studies fail to accurately analyze AoI in specific scenarios, and the impact of backoff algorithms on AoI and PAoI remains to be thoroughly investigated. To optimize these two metrics simultaneously and improve access performance, this article proposes a joint backoff algorithm based on information freshness and NE equalization. First, to address the issues of low-data transmission efficiency and inaccurate decision making in S-IoT, discrete time Markov chains are introduced to assess the information freshness under S-IoT, and the relationship between the node’s retreat phase and PAoI is depicted. Second, to solve the problem of access congestion in S-IoT, the satellite coverage area is divided into different levels according to the threshold value of the spreading factor. A access strategy consistent with the NE equilibrium is defined, a revenue function based on the probability of successful transmission is designed, and a closed form mixed strategy Nash equilibrium (NE) is found using an optimization method. Finally, a value differentiated joint backoff algorithm based on information freshness and NE equalization is proposed. The simulation results show that the algorithm can improve the system throughput rate and reduce the average PAoI and AoI under S-IoT.