Impacts of User Association and Power Control on AoI in Multi-Tier Cellular-Based IoT Networks

In this letter, we study the age of information (AoI) of a
${K}$
-tier cellular Internet-of-Things (IoTs) network by taking into account both weighted path loss association policy and fractional power control strategy. By adopting tools from stochastic geometry, we first obtain the conditional per-tier AoI and conditional success probability, and then derive the tractable expression for average AoI. The proposed analytical framework can be used to evaluate the impacts of weight association ratio of different base station (BS) tiers and power control factor on average AoI. Numerical results verify the correctness of our analysis and reveal the following two conclusions: i) the nearest association policy (i.e., with weight association ratio being 0dB) is optimal to both average AoI and overall success probability; ii) the power control factor has significant impact on average AoI, where the optimal power control factor for average AoI is larger than that for overall success probability.