eprintid: 10044520 rev_number: 21 eprint_status: archive userid: 608 dir: disk0/10/04/45/20 datestamp: 2018-03-05 15:58:37 lastmod: 2021-10-23 22:56:48 status_changed: 2018-03-05 15:58:37 type: article metadata_visibility: show creators_name: Tang, J creators_name: So, DKC creators_name: Zhao, N creators_name: Shojaeifard, A creators_name: Wong, KK title: Energy Efficiency Optimization with SWIPT in MIMO Broadcast Channels for Internet of Things ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F46 keywords: Simultaneous wireless information and power transfer (SWIPT), energy efficiency (EE), multiple-input multiple-output (MIMO), Internet-of-Things (IoT). note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: IEEE Simultaneous wireless information and power transfer (SWIPT) is anticipated to have great applications in fifth-generation (5G) communication systems and the Internet-of-Things (IoT). In this paper, we address the energy efficiency (EE) optimization problem for SWIPT multiple-input multiple-output broadcast channel (MIMO-BC) with time-switching (TS) receiver design. Our aim is to maximize the EE of the system whilst satisfying certain constraints in terms of maximum transmit power and minimum harvested energy per user. The coupling of the optimization variables, namely, transmit covariance matrices and TS ratios, leads to an EE problem which is non-convex, and hence very difficult to solve directly. Hence, we transform the original maximization problem with multiple constraints into a suboptimal min-max problem with a single constraint and multiple auxiliary variables. We propose a dual inner/outer layer resource allocation framework to tackle the problem. For the inner-layer, we invoke an extended SWIPT-based BC-multiple access channel (MAC) duality approach and provide two iterative resource allocation schemes under fixed auxiliary variables for solving the dual MAC problem. A sub-gradient searching scheme is then proposed for the outer-layer in order to obtain the optimal auxiliary variables. Numerical results confirm the effectiveness of the proposed algorithms and illustrate that significant performance gain in terms of EE can be achieved by adopting the proposed extended BC-MAC duality-based algorithm. date: 2018-08 date_type: published official_url: https://doi.org/10.1109/JIOT.2017.2785861 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1525424 doi: 10.1109/JIOT.2017.2785861 lyricists_name: Shojaeifard, Arman lyricists_name: Wong, Kai-Kit lyricists_id: ASHOJ33 lyricists_id: KWONG98 actors_name: Wong, Kai-Kit actors_id: KWONG98 actors_role: owner full_text_status: public publication: IEEE Internet of Things Journal volume: 5 number: 4 pagerange: 2605-2619 issn: 2327-4662 citation: Tang, J; So, DKC; Zhao, N; Shojaeifard, A; Wong, KK; (2018) Energy Efficiency Optimization with SWIPT in MIMO Broadcast Channels for Internet of Things. IEEE Internet of Things Journal , 5 (4) pp. 2605-2619. 10.1109/JIOT.2017.2785861 <https://doi.org/10.1109/JIOT.2017.2785861>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10044520/1/IoT%20Journal.pdf