  We consider a scenario where a base station (BS) attempts to collect fresh
information from power constrained sensors over time-varying band-limited
wireless channels. We characterize the data freshness through the recently
proposed metric--the Age of Information. We consider a time-varying channel
model with power adaptation. Unlike previous work, packet loss may happen due
to imperfect channel estimation or decoding error. We propose an asymptotic
optimal scheduling algorithm minimizing AoI performance and satisfying both
bandwidth and power constraint in such networks. Numerical simulations show
that the proposed policy outperforms the greedy one, and we observe that
sensors with poor channels are scheduled at higher AoI in order to limit the
packet loss.
