Spectral and Energy Efficiencies in Full-Duplex Wireless Information and Power Transfer

Spectral and Energy Efficiencies in Full-Duplex Wireless Information and Power Transfer



A communication system is considered consisting of a full-duplex (FD) multiple-antenna base station (BS) and multiple single-antenna downlink users (DLUs) and single-antenna uplink users (ULUs), where the latter need to harvest energy for transmitting information to the BS. The communication isthus divided into two phases. In the first phase, the BS uses allavailable antennas for conveying information to DLUs and wireless energy to ULUs via information and energy beam forming,respectively. In the second phase, ULUs send their independent information to the BS using their harvested energy while theBS transmits the information to the DLUs. In the both phases,the communication is operated at the same time and over thesame frequency band. The aim is to maximize the sum rate andenergy efficiency under ULU achievable information throughput constraints by jointly designing beamformers and time allocation.The utility functions of interest are nonconcave and involved constraints are nonconvex, so these problems are computationally troublesome. To address them, path-following algorithms are proposed to arrive at least at local optima. The proposed algorithms iteratively improve the objectives with converge guaranteed.Simulation results demonstrate that they achieve fast convergencerate and outperform conventional solutions.


We propose a new model for WPCNs to optimize simultaneous uplink and downlink information transmission by exploring FD radio for the BS.

  • Assuming perfect channel state information (CSI), we first develop a path-following algorithm of low complexity for the computational solution of sum rate maximization (SRM). The obtained solutions are at least local optima as they satisfy the Karush-Kuhn-Tucker (KKT) conditions.
  • Numerical results show fast convergence of the proposed algorithm and greatly improve the system performance over the conventional approaches.
  • The energy efficiency maximization (EEM) problem is a difficult nonlinear fraction program since the objective is not a ratio of a concave and convex function.
  • The commonly-used Dinkelbach-type algorithms are not applicable.
  • We develop a novel path-following algorithm that only invokes one simple convex quadratic program at each iteration, which again converges at least to a local optimum.


Radio-frequency (RF) energy harvesting (EH) communication has emerged as a promising cost-effective technology for supplying power to users. Enabling wireless devices to harvest energy from RF signals, RF-EH communication is expected to fundamentally reshape the landscape of power supply in Internet-of-Things (IoT). Exploring RF EH communication allows one to transfer information and energy over the same RF channel. Various cooperative schemes with/without built-in batteries for energy storage in which multiple transceiver pairs communicate with each other via EH relays were studied. In this regard, transmit beam forming is used to focus information and/or RF energy at the desired users. An emerging trend is the development of wireless powered communication networks (WPCNs), which implement a downlink wireless energy transfer (DWET) followed by an uplink wireless information transmission (UWIT). A base station (BS) first transfers energy to the wireless powered users, who harvest the energy for transmitting their independent information to the BS. Time allocation for DWET and UWIT to optimize the sum information rate subject to per-user achievable information rate thresholds was considered.


  1. Nguyen, L.-N. Tran, P. Pirinen, and M. Latva-aho, “Precoding for full duplex multiuser MIMO systems: Spectral and energy efficiency maximization,” IEEE Trans. Signal Process., vol. 61, no. 16, pp. 4038– 4050, Aug. 2013.

FD multiple input multiple-output (MIMO) pre-coding was studied in the context of multi user MIMO (MU-MIMO) to improve the overall spectral efficiency of downlink and uplink channels

  1. Akbar, Y. Deng, A. Nallanathan, M. Elkashlan, and A.-H. Aghvami,“Simultaneous wireless information and power transfer in K-tier heterogeneous cellular networks,” IEEE Trans. Wireless Commun., vol. 15,no. 8, pp. 5804–5817, Aug. 2016.

Considered a joint downlink (DL) and uplink(UL) transmission of K-tier heterogeneous cellular networks with downlink simultaneous wireless information and power transfer, where outage probability and ergodic capacity of both DL and UL have been derived.


In this paper, a MIMO FD BS in WPCNs has been studied in which the users in the UL channel are designed to harvest energy from the BS before transmitting their information. Tocombat the degree-of-freedom bottleneck, a cooperative transmit strategy between the DL and UL transmission has been proposed. We have developed path-following algorithms for jointly designing the energy harvesting time and beam forming to maximize the sum rate and energy efficiency of the FD system. The proposed algorithms are guaranteed to converge monotonically to at least local optima of the non convex design problems.


Spectral and Energy Efficiencies in Full


We consider a WPCN as illustrated which consists of a BS, K DLUs and L ULUs. The BS is equipped with M receive and N transmit antennas, while all the users are equipped with a single antenna. Denote by D , {D1;D2; _ _ _ ;DK} and U , {U1;U2; _ _ _ ;UL} the sets of DLUs and ULUs, respectively. All channels are assumed to follow independent quasi-static flat fading, i.e., remaining constant during a communication time block, denoted by T, but change independently from one block to another. Without loss of generality, the time block T is set as all ULUs U` 2 U are assumed to harvest energy from the RF signal transmitted by the BS and then transmit information to BS as illustrated.


  • Numerical results have been presented to show the fast convergence rate and demonstrate the advantages of our proposed algorithms.
  • Efficacy of the proposed cooperative transmission in enhancing system performance, as well as the necessity of optimizing energy beam forming in order to provide significant performance improvement compared to the existing solutions.



  • System : Pentium Dual Core.
  • Hard Disk : 120 GB.
  • Monitor : 15’’ LED
  • Input Devices : Keyboard, Mouse
  • Ram : 1GB


  • Operating system : Windows 7.
  • Coding Language : MATLAB
  • Tool : MATLAB R2013A


Van-Dinh Nguyen, Student Member, IEEE, Trung Q. Duong, Senior Member, IEEE, Hoang Duong Tuan,Oh-Soon Shin, Member, IEEE, and H. Vincent Poor Fellow, IEEE, “Spectral and Energy Efficiencies in Full-Duplex Wireless Information and Power Transfer”, IEEE Transactions on Communications, 2017.

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