  This paper investigates the tradeoff between the average age of information
(AoI) and the transmission cost for networks with stochastic packet arrival and
random erasure channel. Specifically, we model the resource-constrained AoI
minimization problem as a constrained Markov decision process (CMDP) and
propose a low-complexity single threshold packet scheduling policy for it. The
key advantage of the proposed policy is its tractability and convenience for
implementation. The AoI distribution and long-term average transmission cost of
the proposed policy are derived as closed-form functions of the selected
threshold. Furthermore, we show that the proposed policy reduces to the optimal
policies under special settings and achieves close-to-optimal performance under
general settings.
