Spectral and Energy-Efficient Wireless Powered IoT Networks: NOMA or TDMA?

Wu Q, Chen W, Wing Kwan Ng D, Schober R (2018)

Publication Language: English

Publication Type: Journal article

Publication year: 2018

Journal

IEEE Transactions on Vehicular Technology Institute of Electrical and Electronics Engineers (IEEE)

Book Volume: 67

Pages Range: 6663 - 6667

Journal Issue: 7

DOI: 10.1109/TVT.2018.2799947

Abstract

Wireless powered communication networks (WPCNs), where multiple energy-limited devices first harvest energy in the downlink and then transmit information in the uplink, have been envisioned as a promising solution for the future Internet-of-Things (IoT). Meanwhile, nonorthogonal multiple access (NOMA) has been proposed to improve the system spectral efficiency (SE) of the fifth-generation (5G) networks by allowing concurrent transmissions of multiple users in the same spectrum. As such, NOMA has been recently considered for the uplink of WPCNs based IoT networks with a massive number of devices. However, simultaneous transmissions in NOMA may also incur more transmit energy consumption as well as circuit energy consumption in practice which is critical for energy constrained IoT devices. As a result, compared to orthogonal multiple access schemes such as time-division multiple access (TDMA), whether the SE can be improved and/or the total energy consumption can be reduced with NOMA in such a scenario still remains unknown. To answer this question, we first derive the optimal time allocations for maximizing the SE of a TDMA-based WPCN (T-WPCN) and a NOMA-based WPCN (N-WPCN), respectively. Subsequently, we analyze the total energy consumption as well as the maximum SE achieved by these two networks. Surprisingly, it is found that N-WPCN not only consumes more energy, but also is less spectral efficient than T-WPCN. Simulation results verify our theoretical findings and unveil the fundamental performance bottleneck, i.e., “worst user bottleneck problem”, in multiuser NOMA systems.

Authors with CRIS profile

Robert Schober Lehrstuhl für Digitale Übertragung

Involved external institutions

National University of Singapore (NUS)

Singapore (SG) University of New South Wales (UNSW)

Australia (AU) Shanghai Jiao Tong University / 上海交通大学

China (CN)

How to cite

APA:

Wu, Q., Chen, W., Wing Kwan Ng, D., & Schober, R. (2018). Spectral and Energy-Efficient Wireless Powered IoT Networks: NOMA or TDMA? IEEE Transactions on Vehicular Technology, 67(7), 6663 - 6667. https://doi.org/10.1109/TVT.2018.2799947

MLA:

Wu, Qingqing, et al. "Spectral and Energy-Efficient Wireless Powered IoT Networks: NOMA or TDMA?" IEEE Transactions on Vehicular Technology 67.7 (2018): 6663 - 6667.

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