Optimal scheduling and power allocation for two-hop energy harvesting communication systems

Y. Luo, Jun Zhang, K.B. Letaief

Research output: Journal article publicationJournal articleAcademic researchpeer-review

121 Citations (Scopus)


Energy harvesting (EH) has recently emerged as a promising technique for green communications. To realize its potential, communication protocols need to be redesigned to combat the randomness of the harvested energy. In this paper, we investigate how to apply relaying to improve the short-term performance of EH communication systems. With an EH source and a non-EH half-duplex relay, we consider two different design objectives: 1) short-term throughput maximization; and 2) transmission completion time minimization. Both problems are joint colorblack{time scheduling} and power allocation problems, rendered quite challenging by the half-duplex constraint at the relay. A key finding is that directional water-filling (DWF), which is the optimal power allocation algorithm for the single-hop EH system, can serve as guideline for the design of two-hop communication systems, as it not only determines the value of the optimal performance, but also forms the basis to derive optimal solutions for both design problems. Based on a relaxed energy profile along with the DWF algorithm, we derive key properties of the optimal solutions for both problems and thereafter propose efficient algorithms. Simulation results will show that both colorblack{time scheduling }and power allocation optimizations are necessary in two-hop EH communication systems. © 2013 IEEE.
Original languageEnglish
Article number6585724
Pages (from-to)4729-4741
Number of pages13
JournalIEEE Transactions on Wireless Communications
Issue number9
Publication statusPublished - 7 Oct 2013
Externally publishedYes


  • directional water-filling
  • Energy harvesting
  • power allocation
  • time scheduling
  • two-hop transmission

ASJC Scopus subject areas

  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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