The Effect of Imperfect Feedback on Age-Threshold Slotted ALOHA

We analyze the age-threshold slotted ALOHA (TSA) protocol in a Poisson cellular network, considering potential ACK feedback errors. In this setup, spatially distributed nodes must update their status information to a designated access point over a shared spectrum. The TSA protocol requires source nodes to remain silent until their local Age of Information (AoI) reaches a preset threshold, after which each node independently decides whether to transmit in the current time slot with a certain probability. With imperfect ACK feedback, the source node may fail to reset its local AoI when ACK feedback error occur, causing the age-threshold policy to become temporarily ineffective. Based on this setting, we derive analytical expressions for the transmission success probability and the network average AoI. Our findings demonstrate that imperfect ACK feedback significantly affects the performance limits of network average AoI when employing the TSA protocol.