Energy-Age Tradeoff in Status Update Communication Systems with Retransmission

TL;DR

This paper analyzes the balance between data freshness and energy use in status update systems with retransmissions, deriving formulas for average age-of-information and energy consumption under channel errors.

Contribution

It introduces a threshold-based retransmission policy and provides closed-form expressions for age and energy metrics considering channel errors and retransmission limits.

Findings

Analytical formulas for average age-of-information and energy consumption.

Tradeoff illustration between data freshness and energy efficiency.

Validation of results through numerical simulations.

Abstract

Age-of-information is a novel performance metric in communication systems to indicate the freshness of the latest received data, which has wide applications in monitoring and control scenarios. Another important performance metric in these applications is energy consumption, since monitors or sensors are usually energy constrained. In this paper, we study the energy-age tradeoff in a status update system where data transmission from a source to a receiver may encounter failure due to channel error. As the status sensing process consumes energy, when a transmission failure happens, the source may either retransmit the existing data to save energy for sensing, or sense and transmit a new update to minimize age-of-information. A threshold-based retransmission policy is considered where each update is allowed to be transmitted no more than M times. Closed-form average age-of-information and energy consumption is derived and expressed as a function of channel failure probability and maximum number of retransmissions M. Numerical simulations validate our analytical results, and illustrate the tradeoff between average age-of-information and energy consumption.