Energy efficiency optimization for MISO SWIPT systems with zero-forcing beamforming

Qingjiang Shi, Cheng Peng, Weiqiang Xu, Mingyi Hong, Yunlong Cai

Research output: Contribution to journalArticlepeer-review

124 Scopus citations


This paper considers a power splitting based multiuser multiple-input-single-output (MISO) downlink system with simultaneous wireless information and power transfer, where each single antenna receiver splits the received signal into two streams of different power for decoding information and harvesting energy separately. Assuming that the most common zero-forcing (ZF) beamforming scheme is employed by the base station, we aim to maximize the system energy efficiency in bits per Joule by joint beamforming and power splitting under both the signal-to-interference-plus-noise ratio constraints and energy harvesting constraints. The energy efficiency optimization (EEO) problem is nonconvex and very hard to solve. In this paper, by exploiting the problem structure, we first simplify the EEO problem to a joint transmit power allocation and receive power splitting problem. Then, with a tactful reformulation, we propose a Lagrangian relaxation (LR) method coupled with Dinkelbach method to address the simplified EEO problem, whilst devising a nearly closed-form solution for the subproblems involved in the Dinkelbach method. It is proven that the proposed LR method is optimum under some condition and can guarantee at least a feasible solution, which is a notable advantage over the existing methods. Besides, we develop a low complexity EEO algorithm by proportionally distributing the total power to users. Finally, numerical results validate the excellent efficiency of the proposed algorithms.

Original languageEnglish (US)
Article number7307218
Pages (from-to)842-854
Number of pages13
JournalIEEE Transactions on Signal Processing
Issue number4
StatePublished - Feb 15 2016

Bibliographical note

Publisher Copyright:
© 2015 IEEE.


  • Dinkelbach method
  • Lagrangian relaxation method
  • multiuser MISO downlink
  • power splitting
  • wireless information and power transfer
  • zero-forcing beamforming


Dive into the research topics of 'Energy efficiency optimization for MISO SWIPT systems with zero-forcing beamforming'. Together they form a unique fingerprint.

Cite this