Average Age of Sensing in Multi-Cycle Sensing and Communication Applications With Wireless Power Transfer

Abstract

Distinct from conventional integrated sensing and communication (ISAC) techniques, breakthroughs in LoRa-aided ISAC achieve hardware-unified sensing and communication capabilities for low-power devices. By combining such a novel technology with wireless power transfer (WPT), it yields wireless powered sensing and communication networks (WPSCNs). Information fusion, a widely adopted technique in such networks, relies heavily on the fresh fused information for effective system decision-making. However, age of information (AoI) is ineffective for measuring freshness of fused information. To tackle this dilemma, a novel metric, age of sensing (AoS), is introduced. Specifically, we study timeliness of a WPSCN, where a fusion center (FC) wirelessly powers sensing nodes (SNs) to collect sensing information from the SNs for generating fused information. Moreover, the impact of multi-cycle sensing on the AoS is first explored in the WPSCNs. We also adopt the adaptive transmission strategy for flexibly reducing the transmission duration. After obtaining a closed-form of the average AoS, it is then minimised by optimising WPT duration, multi-cycle sensing strategy and the SN locations. Ultimately, the numerical results validate the accuracy of our theoretical analysis. The effect of multi-cycle sensing and the superiority of adaptive transmission strategy are also demonstrated. Our findings offer valuable insights for analysing and improving the fusion system timeliness, and provide a theoretical foundation for the practical deployment of the WPSCNs.