Age-Optimal Multi-Slot Pilot Allocation Random Access Protocol for S-IoT
Tao Yang, Jian Jiao, Liang Xu, Shaohua Wu, Qinyu Zhang · 2021
The timeliness of information is important for massive machine type communications (mMTC) random access in satellite internet of things (S-IoT), where the propagation delay would hinder the terrestrial sensing devices update their timely status to the satellite. In this paper, we analyse the timeliness of information for the mMTC random access scenario via a new performance metric named age of information (AoI), and propose an age-optimal multi-slots pilot allocation random access (AMSPA) protocol, which aims to lower the system average AoI with a certain access failure probability (AFP) requirement. We derive the closed-form expression of the system average AoI by tracking the AoI evolution of each device via Markovian analysis, then we conduct an optimal number of slots to achieve the lowest system average AoI with the increasing of the system overload. Simulation results validate our theoretical analysis and show that we can minimize the system average AoI via choosing an optimal number of slots under diversity system load for our AMSPA protocol.