Harvest-Or-Access: Slotted ALOHA for Wireless Powered Communication Networks

Hyun Ho Choi, Wonjae Shin, Marco Levorato, H. Vincent Poor

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


This paper proposes a distributed energy-harvesting random access protocol called harvest-or-access by applying slotted ALOHA to wireless powered communication networks (WPCNs). From the fact that there are a considerable number of idle slots during which any nodes do not attempt transmission in slotted ALOHA, the idle slots are made available for wireless energy transfer (WET). If any random access (RA) slot is recognized as an idle slot, the hybrid access point (HAP) opportunistically performs the WET in this slot. The wireless devices (WDs) can harvest energy for every idle slot and attempt random access by using this harvested energy. An asymptotic throughput analysis in a high signal-to-noise ratio (SNR) environment with a sufficient number of accessing WDs shows that there is an optimal number of RA slots allocated to maximize throughput and this optimal number of RA slots depends only on the average of the minimum SNRs of the WDs without knowledge of full channel state information. Monte Carlo simulation results further show that the proposed harvest-or-access protocol outperforms the conventional harvest-then-transmit-based random access protocols especially when the number of WDs is large.

Original languageEnglish (US)
Article number8794617
Pages (from-to)11394-11398
Number of pages5
JournalIEEE Transactions on Vehicular Technology
Issue number11
StatePublished - Nov 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Electrical and Electronic Engineering
  • Computer Networks and Communications
  • Automotive Engineering


  • Wireless powered communication networks
  • energy harvesting
  • random access
  • slotted ALOHA


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