  It is becoming increasingly clear that an important task for wireless
networks is to minimize the age of information (AoI), i.e., the timeliness of
information delivery. While mainstream approaches generally rely on the
real-time observation of user AoI and channel state, there has been little
attention to solve the problem in a complete (or partial) absence of such
knowledge. In this article, we present a novel study to address the optimal
blind radio resource scheduling problem in orthogonal frequency division
multiplexing access (OFDMA) systems towards minimizing long-term average AoI,
which is proven to be the composition of time-domain-fair clustered round-robin
and frequency-domain-fair intra-cluster sub-carrier assignment. Heuristic
solutions that are near-optimal as shown by simulation results are also
proposed to effectively improve the performance upon presence of various
degrees of extra knowledge, e.g., channel state and AoI.
