Sum-Throughput Maximization in NOMA-Based WPCN: A Cluster-Specific Beamforming Approach

Dongyeong Song, Wonjae Shin, Jungwoo Lee, H. Vincent Poor

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Wireless power transfer is a promising solution for wireless networks composed of Internet-of-Things (IoT) devices that may suffer from insufficient battery capacity. A wireless powered communication network (WPCN) is a framework to design energy-constrained networks such as IoT networks. In this article, we consider WPCNs consisting of a hybrid access point (H-AP) and energy harvesting users, all equipped with multiple antennas. A H-AP transfers energy to the users using energy beamforming in the downlink, and the users transmit information using the harvested energy in the uplink, where nonorthogonal multiple access (NOMA) transmission is employed. For the uplink NOMA transmission, users are grouped into multiple clusters by cluster-specific beamforming. In particular, signal alignment is exploited for the beamforming so that the channels of users in a cluster are aligned in the same direction. By signal alignment, the number of messages decoded by successive interference cancellation (SIC) is reduced, which can be effective at lowering the decoding complexity and SIC error propagation. Due to the difficulty of jointly optimizing cluster-specific beamforming and time/energy resources for sum-throughput maximization, we determine the beamforming relying on signal alignment first, and then the resources are optimized for given beamforming. To be more specific, we propose a novel iterative algorithm for cluster-specific beamforming design followed by the sum-throughput maximization algorithm. Numerical results show the sum-throughput performance of the proposed scheme and its robustness toward SIC error propagation compared to existing schemes.

Original languageEnglish (US)
Article number9316713
Pages (from-to)10543-10556
Number of pages14
JournalIEEE Internet of Things Journal
Issue number13
StatePublished - Jul 1 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Information Systems
  • Hardware and Architecture
  • Computer Science Applications
  • Computer Networks and Communications


  • Beamforming
  • Convex optimization
  • Nonorthogonal multiple access (NOMA)
  • Successive interference cancelation (SIC)
  • Sum-throughput
  • User cluster
  • Wireless powered communication network (WPCN)


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