TY - JOUR
T1 - Sum-Throughput Maximization in NOMA-Based WPCN
T2 - A Cluster-Specific Beamforming Approach
AU - Song, Dongyeong
AU - Shin, Wonjae
AU - Lee, Jungwoo
AU - Poor, H. Vincent
N1 - Funding Information:
Manuscript received May 12, 2020; revised November 26, 2020; accepted December 23, 2020. Date of publication January 8, 2021; date of current version June 23, 2021. This work was supported in part by the Basic Science Research Programs under the National Research Foundation of Korea (NRF) through the Ministry of Science and ICT under Grant NRF-2019R1C1C1006806; in part by the Office for Naval Research Global under Grant N62909-20-1-2056; in part by the U.S. National Science Foundation under Grant CCF-1908308; in part by MSIT-IITP under Grant 2019-0-01367, BabyMind; in part by INMAC; and in part by BK21-plus. (Corresponding author: Wonjae Shin.) Dongyeong Song and Jungwoo Lee are with the Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, South Korea (e-mail: dysong@cml.snu.ac.kr; junglee@snu.ac.kr).
Publisher Copyright:
© 2014 IEEE.
PY - 2021/7/1
Y1 - 2021/7/1
N2 - 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.
AB - 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.
KW - Beamforming
KW - Convex optimization
KW - Nonorthogonal multiple access (NOMA)
KW - Successive interference cancelation (SIC)
KW - Sum-throughput
KW - User cluster
KW - Wireless powered communication network (WPCN)
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U2 - 10.1109/JIOT.2021.3049956
DO - 10.1109/JIOT.2021.3049956
M3 - Article
AN - SCOPUS:85099545905
SN - 2327-4662
VL - 8
SP - 10543
EP - 10556
JO - IEEE Internet of Things Journal
JF - IEEE Internet of Things Journal
IS - 13
M1 - 9316713
ER -