Age of Information Minimization for an Energy Harvesting Source with Updating Erasures: Without and with Feedback

Songtao Feng, Jing Yang

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


Consider an energy harvesting (EH) sensor that continuously monitors a system and sends time-stamped status update to a destination. The sensor harvests energy from nature and uses it to power its updating operations. The destination keeps track of the system status through the successfully received updates. With the recently introduced information freshness metric 'Age of Information' (AoI), our objective is to design optimal online status updating policy to minimize the long-Term average AoI at the destination, subject to the energy causality constraint at the sensor. Due to the noisy channel between the sensor and the destination, each transmitted update may be erased with a fixed probability, and the AoI at the destination will be reset to zero only when an update is successfully received. We first consider status updating without feedback available to the sensor and show that the Best-effort Uniform updating (BU) policy is optimal in a broadly defined class of online policies. We then investigate status updating with perfect feedback to the sensor and prove similar optimality of the Best-effort Uniform updating with Retransmission (BUR) policy. In order to prove the optimality of the proposed policies, for each case, we first identify a lower bound on the long-Term average AoI among a broad class of online policies, and then construct a sequence of virtual policies to approach the lower bound asymptotically. Since those virtual policies are sub-optimal to the original policy, the original policy is thus optimal.

Original languageEnglish (US)
Article number9440981
Pages (from-to)5091-5105
Number of pages15
JournalIEEE Transactions on Communications
Issue number8
StatePublished - Aug 2021

All Science Journal Classification (ASJC) codes

  • Electrical and Electronic Engineering


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