Age of Information in the Presence of an Adversary

TL;DR

This paper analyzes how an adversary can optimally disrupt the timeliness of information in a wireless communication system by blocking consecutive time slots, revealing the strategic nature of such attacks.

Contribution

It characterizes the optimal adversarial strategy for minimizing information freshness under a blocking constraint in a multi-user wireless system.

Findings

Optimal adversary blocks $oldsymbol{ ext{alpha} T}$ consecutive slots.

Consecutive blocking is optimal due to age metric properties.

Results inform design of robust communication protocols.

Abstract

We consider a communication system where a base station serves $N$ users, one user at a time, over a wireless channel. We consider the timeliness of the communication of each user via the age of information metric. A constrained adversary can block at most a given fraction, $\alpha$, of the time slots over a horizon of $T$ slots, i.e., it can block at most $\alpha T$ slots. We show that an optimum adversary blocks $\alpha T$ consecutive time slots of a randomly selected user. The interesting consecutive property of the blocked time slots is due to the cumulative nature of the age metric.