A Unified Analysis of Slotted Aloha with Stochastic Arrivals: Transmission Probability Control versus Age Threshold Control

Two fundamental channel contention control strategies in slotted Aloha for improving the information freshness are the transmission probability control and the age threshold control. Yet, a unified analysis and performance comparison between them remains unexplored, particularly when the arrival process of updates follows a stochastic manner, instead of ondemand manner. This paper addresses the above issue by establishing a unified analytical framework of slotted Aloha for including both strategies. Key performance measures, such as network steady-state point, peak age of information and energy efficiency, are derived as explicit functions of the transmission probability, the age threshold and other system input parameters. The joint effect of those two control strategies on age performance are demonstrated, which further reveals the optimal joint tuning of transmission probability and threshold for age minimization. The comparison shows that the transmission probability control is indispensable, while the age threshold control is beneficial for stabilizing the network age performance.