Online Energy Minimization Under A Peak Age of Information Constraint

TL;DR

This paper studies how to minimize energy consumption in a data transmission system while keeping the peak age of information below a threshold, using causal policies and analyzing their performance relative to an optimal offline policy.

Contribution

It derives a lower bound on the competitive ratio for causal policies and proposes a policy that approaches this bound, advancing understanding of energy-efficient AoI management.

Findings

Lower bound on the competitive ratio derived

Proposed policy achieves near-optimal competitive ratio

Analysis depends on system parameters like power function and AoI threshold

Abstract

We consider a node where packets of fixed size (in bits) are generated at arbitrary intervals. The node is required to maintain the peak age of information (AoI) at the monitor below a threshold by transmitting potentially a subset of the generated packets. At any time, depending on the packet availability and the current AoI, the node can choose which packet to transmit, and at what transmission speed (in bits per second). Power consumption is a monotonically increasing convex function of the transmission speed. In this paper, for any given time horizon, the objective is to find a causal policy that minimizes the total energy consumption while satisfying the peak AoI constraint. We consider competitive ratio as the performance metric, that is defined as the ratio of the expected cost of a causal policy, and the expected cost of an optimal offline policy that knows the input (packet generation times) in advance. We first derive a lower bound on the competitive ratio of all causal policies, in terms of the system parameters (such as power function, packet size and peak AoI threshold), and then propose a particular policy for which we show that its competitive ratio has similar order of dependence on the system parameters as the derived lower bound.