Performance Analysis for Correlated AoI and Energy Efficiency in Heterogeneous CR-IoT System

TL;DR

This paper analyzes the tradeoff between energy efficiency and information freshness in a heterogeneous CR-IoT system, deriving formulas and proposing an optimal power control algorithm.

Contribution

It provides closed-form expressions for energy efficiency and AoI, and introduces an optimal transmit power algorithm considering traffic heterogeneity.

Findings

Optimal transmit power balances energy efficiency and AoI.

Heterogeneous traffic patterns significantly affect system performance.

Numerical results demonstrate the effectiveness of the proposed optimization.

Abstract

We consider a cognitive radio based Internet of Things (CR-IoT) system where the secondary IoT device (SD) accesses the licensed channel during the transmission vacancies of the primary IoT device (PD). We focus on the impact of the IoT devices' heterogeneous traffic pattern on the energy efficiency and on the age of information (AoI) performance of the SD. We first derive closed-form expressions of the energy efficiency and the average AoI, and subsequently explore their convexity and monotonicity to the transmit power. Following these characterizations, an optimal transmit power optimization algorithm (TPOA) is proposed for the SD to maximize the energy efficiency while maintaining the average AoI under a predefined threshold. Numerical results verify the different preferences of the SD toward different PD traffic patterns, and provides insights into the tradeoff between the energy efficiency and the average AoI.