Energy Harvesting Capability Research Articles

Energy harvesting and wireless communication by carbon fiber-reinforced polymer-enhanced piezoelectric nanocomposites

Piezoelectric Internet of Things (IoT) sensors with energy-harvesting capabilities, which can convert mechanical energy into electrical energy, promote battery-less systems. Such sensors can harness the vibration generated by spacecraft and other moving objects, eliminating the need for external power sources or battery replacements, thereby improving the autonomy and reliability of the system. This study investigates the features of a novel piezoelectric vibration energy harvester (PVEH) that comprises a carbon fiber-reinforced polymer (CFRP) electrode. The CFRP electrode provides outstanding electrical conductivity (7190 S/m) and enhances the mechanical characteristics of the energy collector, thereby ensuring a steady electrical energy yield during resonance. The piezoelectric composite consists of potassium sodium niobate (KNN) nanoparticles mixed with epoxy resin. Results show that when the KNN content is about 30 vol%, the piezoelectric properties of d33 and d31 are 15.21 pC/N and − 5.68 pC/N, respectively. Under an applied displacement of 0.05 mm, the CFRP-reinforced PVEH (C-PVEH) provides an impressive output energy volume density of 89.61 μW/cm3, which is capable of lighting LED bulbs with ease. Notably, this technology shows great application potential for powering wireless communication systems, indicating a remarkable advancement in the field of self-powered IoT sensors. This study provides valuable insights into the potential application of this groundbreaking technology.

Linear Segmented Arc-Shaped Piezoelectric Branch Beam Energy Harvester for Ultra-Low Frequency Vibrations.

Piezoelectric energy harvesting systems have been drawing the attention of the research community over recent years due to their potential for recharging/replacing batteries embedded in low-power-consuming smart electronic devices and wireless sensor networks. However, conventional linear piezoelectric energy harvesters (PEH) are often not a viable solution in such advanced practices, as they suffer from a narrow operating bandwidth, having a single resonance peak present in the frequency spectrum and very low voltage generation, which limits their ability to function as a standalone energy harvester. Generally, the most common PEH is the conventional cantilever beam harvester (CBH) attached with a piezoelectric patch and a proof mass. This study investigated a novel multimode harvester design named the arc-shaped branch beam harvester (ASBBH), which combined the concepts of the curved beam and branch beam to improve the energy-harvesting capability of PEH in ultra-low-frequency applications, in particular, human motion. The key objectives of the study were to broaden the operating bandwidth and enhance the harvester's effectiveness in terms of voltage and power generation. The ASBBH was first studied using the finite element method (FEM) to understand the operating bandwidth of the harvester. Then, the ASBBH was experimentally assessed using a mechanical shaker and real-life human motion as excitation sources. It was found that ASBBH achieved six natural frequencies within the ultra-low frequency range (<10 Hz), in comparison with only one natural frequency achieved by CBH within the same frequency range. The proposed design significantly broadened the operating bandwidth, favouring ultra-low-frequency-based human motion applications. In addition, the proposed harvester achieved an average output power of 427 μW at its first resonance frequency under 0.5 g acceleration. The overall results of the study demonstrated that the ASBBH design can achieve a broader operating bandwidth and significantly higher effectiveness, in comparison with CBH.

Functionality Tuning in Hierarchically Engineered Magnetoelectric Nanocomposites for Energy-Harvesting Applications.

The β-phase of the copolymer poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) possesses the highest dipole moment among all the functional polymers. It remains a key component of flexible energy-harvesting devices based on piezoelectricity and triboelectricity in the last decade. However, the quest for P(VDF-TrFE)-based magnetoelectric (ME) nanocomposites with enhanced ferroelectric, piezoelectric, and triboelectric properties remains elusive. The magnetostrictive inclusion in the copolymer matrix forms electrically conducting pathways and degrades β-phase crystallinity significantly, deteriorating the functional properties of the nanocomposite films. To address this issue, we report the synthesis of magnetite (Fe3O4) nanoparticles on micron-scale magnesium hydroxide [Mg(OH)2] templates. These hierarchical structures were incorporated within the P(VDF-TrFE) matrix rendering composites with enhanced energy-harvesting capability. The Mg(OH)2 template prevents the formation of a continuous network of magnetic fillers, leading to lower electrical leakage in the composite. The addition of dual-phase fillers with 5 wt % only increases remanent polarization (Pr) values by ∼44%, owing to the presence of the β-phase with significant crystallinity and increased interfacial polarization. The composite film exhibits a quasi-superparamagnetic nature and a significant magnetoelectric coupling coefficient (αME) of 30 mV/cm Oe. The film was also employed for triboelectric nanogenerator applications, exhibiting five times higher power density than the pristine film. We finally explored the integration of our ME devices with an internet of things platform to monitor the operational status of electrical appliances remotely. In light of these findings, the present work opens the path for future self-powered, multifunctional, and flexible ME devices with new application domains.

Enhanced Piezoelectric, Ferroelectric, and Electrostrictive Properties of Lead-Free (1-x)BCZT-(x)BCST Electroceramics with Energy Harvesting Capability.

Next-generation electronics and energy technologies can now be developed as a result of the design, discovery, and development of novel, environmental friendly lead (Pb)-free ferroelectric materials with improved characteristics and performance. However, there have only been a few reports of such complex materials' design with multi-phase interfacial chemistry, which can facilitate enhanced properties and performance. In this context, herein, novel lead-free piezoelectric materials (1-x)Ba0.95 Ca0.05 Ti0.95 Zr0.05 O3 -(x)Ba0.95 Ca0.05 Ti0.95 Sn0.05 O3 , are reported, which are represented as (1-x)BCZT-(x)BCST, with demonstrated excellent properties and energy harvesting performance. The (1-x)BCZT-(x)BCST materials are synthesized by high-temperature solid-state ceramic reaction method by varying x in the full range (x = 0.00-1.00). In-depth exploration research is performed on the structural, dielectric, ferroelectric, and electro-mechanical properties of (1-x)BCZT-(x)BCST ceramics. The formation of perovskite structure for all ceramics without the presence of any impurity phases is confirmed by X-ray diffraction (XRD) analyses, which also reveals that the Ca2+ , Zr4+ , and Sn4+ are well dispersed within the BaTiO3 lattice. For all (1-x)BCZT-(x)BCST ceramics, thorough investigation of phase formation and phase-stability using XRD, Rietveld refinement, Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and temperature-dependent dielectric measurements provide conclusive evidence for the coexistence of orthorhombic + tetragonal (Amm2 + P4mm) phases at room temperature. The steady transition of Amm2 crystal symmetry to P4mm crystal symmetry with increasing x content is also demonstrated by Rietveld refinement data and related analyses. The phase transition temperatures, rhombohedral-orthorhombic (TR-O ), orthorhombic- tetragonal (TO-T ), and tetragonal-cubic (TC ), gradually shift toward lower temperature with increasing x content. For (1-x)BCZT-(x)BCST ceramics, significantly improved dielectric and ferroelectric properties are observed, including relatively high dielectric constant εr ≈ 1900-3300 (near room temperature), εr ≈ 8800-12900 (near Curie temperature), dielectric loss, tan δ ≈ 0.01-0.02, remanent polarization Pr ≈ 9.4-14 µC cm-2 , coercive electric field Ec ≈ 2.5-3.6kV cm-1 . Further, high electric field-induced strain S ≈ 0.12-0.175%, piezoelectric charge coefficient d33 ≈ 296-360 pC N-1 , converse piezoelectric coefficient ≈ 240-340 pm V-1 , planar electromechanical coupling coefficient kp ≈ 0.34-0.45, and electrostrictive coefficient (Q33 )avg ≈ 0.026-0.038 m4 C-2 are attained. Output performance with respect to mechanical energy demonstrates that the (0.6)BCZT-(0.4)BCST composition (x = 0.4) displays better efficiency for generating electrical energy and, thus, the synthesized lead-free piezoelectric (1-x)BCZT-(x)BCST samples are suitable for energy harvesting applications. The results and analyses point to the outcome that the (1-x)BCZT-(x)BCST ceramics as a potentially strong contender within the family of Pb-free piezoelectric materials for future electronics and energy harvesting device technologies.

The impact of clustering strategies to site integrated community energy and harvesting systems on electrical demand and regional GHG reductions

The current work examines the Integrated Community Energy and Harvesting system (ICE-Harvest), an integration of thermal and electrical distributed energy resources. The system prioritizes the harvesting of community waste energy resources—for example, residual heat rejected from cooling processes and peak electricity fossil-fuel fired generators, as well as energy from curtailed clean grid electricity resources—to help in satisfying the heating demands of commercial and residential buildings. As such, ICE-Harvest systems provide a solution that can minimize greenhouse gas emissions from high-energy-consumption buildings in cold-climate regions such as North America and Northern Europe. The current work focuses on where to locate these systems and introduces different clustering methods for integrated energy systems that focus on thermal load diversity among buildings in each cluster. In the first technique, buildings with the highest amount of rejected heat from their cooling systems (anchor buildings) are clustered with nearby high heating demands buildings to create a large opportunity for harvesting wasted energy however, buildings not located close to anchor buildings are clustered using density-based clustering methods. The energy harvesting capabilities of this technique are compared to those provided by full DB clustering without specifying the anchor buildings, as well as to full density-based clustering with a post-processing step in which the nearest anchor building is added to each cluster. The selected clustering method also demonstrates the grid level potential of the ICE-Harvest systems to impact greenhouse gas emissions, heating, and electricity consumption by presenting a reduced model for the ICE-Harvest system that can be applied to any number of clusters on a municipal or provincial/state scale. Specifically, the model is applied to a database of 14,832 high-energy-consumption buildings with the potential for forming 1,139 clusters in the province of Ontario, Canada. The results of this case study reveal that density-based clustering with post processing resulted in the largest emission reduction per unit piping network length of 360 t CO2eq /km/year. In addition, the use of ICE-Harvest systems can displace the energy required from the gas-fired heating resources by 11 TWh, accounting for over 70% of the clusters’ total heating requirements. This results in a 1.9 Mt CO2eq reduction in overall sites’ emissions, which represents around 60% of the clusters’ emissions.

Tailoring Triple Filler Systems for Improved Magneto-Mechanical Performance in Silicone Rubber Composites.

The demand for multi-functional elastomers is increasing, as they offer a range of desirable properties such as reinforcement, mechanical stretchability, magnetic sensitivity, strain sensing, and energy harvesting capabilities. The excellent durability of these composites is the key factor behind their promising multi-functionality. In this study, various composites based on multi-wall carbon nanotubes (MWCNT), clay minerals (MT-Clay), electrolyte iron particles (EIP), and their hybrids were used to fabricate these devices using silicone rubber as the elastomeric matrix. The mechanical performance of these composites was evaluated, with their compressive moduli, which was found to be 1.73 MPa for the control sample, 3.9 MPa for MWCNT composites at 3 per hundred parts of rubber (phr), 2.2 MPa for MT-Clay composites (8 phr), 3.2 MPa for EIP composites (80 phr), and 4.1 MPa for hybrid composites (80 phr). After evaluating the mechanical performance, the composites were assessed for industrial use based on their improved properties. The deviation from their experimental performance was studied using various theoretical models such as the Guth-Gold Smallwood model and the Halpin-Tsai model. Finally, a piezo-electric energy harvesting device was fabricated using the aforementioned composites, and their output voltages were measured. The MWCNT composites showed the highest output voltage of approximately 2 milli-volt (mV), indicating their potential for this application. Lastly, magnetic sensitivity and stress relaxation tests were performed on the hybrid and EIP composites, with the hybrid composite demonstrating better magnetic sensitivity and stress relaxation. Overall, this study provides guidance on achieving promising mechanical properties in such materials and their suitability for various applications, such as energy harvesting and magnetic sensitivity.

Multifunctional conductive textile for efficient electrothermal conversion and triboelectric nanogenerators

Integration of sensor, energy harvesting and flexible textile has been considered as a promising strategy applied in the fields of wearable electrics, artificial intelligence. Herein, flexible, multifunctional conductive textiles consist of quaternary composites of two-dimensional (2D) vanadium carbides (V2CTx) MXene, highly conductive poly(3, 4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS), liquid metal (LM), and one-dimensional carbon nanotube (CNT) (for simplicity denoted as MPLC) were fabricated to construct a three-dimensional (3D) network with remarkable conductivity and Joule heating properties for applications in wearable heaters and TENG based on-skin sensors by adopting a simple method of dip-coating. The TENG using MPLC as the electrode and the triboelectric layer demonstrates excellent energy harvesting capability. TENG based self-powered sensor shows an open circuit voltage (Voc) of 118.5 V, short circuit current (Isc) of 1.23 μA and maximum output power of 57.12 μW under mechanical friction. In addition, fast Joule heating in response to a saturation temperature of 221 °C at a driving voltage of 3 V is achieved. Our study provides a simple, lightweight, and effective multifunctional system with integrated characteristics of superior sensing and electrothermal conversion, which are highly desired for applications in wearable electronics, intelligent electronics, and personal self-heating system.

Functionally integrated conductive organohydrogel sensor for wearable motion detection, triboelectric nanogenerator and non-contact sensing

In the field of wearable devices, hydrogel has become a new material due to its excellent flexibility and adjustable multifunctionality. However, there are still many problems in practical application, which cannot meet the requirements of people for flexible electronic devices. Herein, a stretchable, self-adhesive, anti-freezing and moisturizing ion-conductive organohydrogel was successfully prepared. This organohydrogel can exhibit adjustable optical properties in different solvents, and the strain sensor based on it can exhibits excellent sensing capability and real-time responsiveness to various strains, pressures and human body. In addition, the organohydrogel exhibits excellent energy harvesting capabilities when it was assembled with Ecoflex elastomers to form a triboelectric nanogenerator (TENG). And when it was assembled with Ecoflex elastomer to form a non-contact capacitive sensor, it can achieve good proximity sensing stability. Therefore, it can be seen that the multifunctional organohydrogel provides an idea for the design and preparation of advanced versatile flexible sensors.

Synchronous Switch Energy Extraction Circuit for Motor Regenerative Braking Enhancement

The synchronous switch technique has been utilized as a promising solution to enhance the energy harvesting capabilities of piezoelectric devices. It utilizes a switched inductive branch to compensate for the capacitive source and increase the real power. The synchronous switch technique was also extended to enhance energy harvesting from electromagnetic (EM) sources. This paper introduces a synchronous switch energy extraction (SSEE) circuit and examinates its performance in motor regenerative braking (RB) enhancement. In the SSEE scheme, a switched capacitive branch is connected to compensate for the inductive source of an electromagnetic motor. The output current from a coil is made in phase with the induced voltage source. The braking power is significantly improved. Therefore, the kinetic energy is extracted much faster to brake the motor quickly, while a portion of the extracted energy is harvested into storable electrical dc energy. This paper comprehensively evaluates the SSEE performances, in terms of energy harvesting and motor braking, respectively. Experimental results show that, given a flywheel released from the same speed, the SSEE can recover 182.5% more energy than the diode-bridge rectifier. For the braking performance, the SSEE can reduce the braking time by 35.1%, compared with the short-circuit braking (SCB) case.

Supersonically sprayed PVDF and ZnO flowers with built-in nanocuboids for wearable piezoelectric nanogenerators

Healthcare implant devices that can internally generate a flow of electrical charge driven by mechanical stimuli are in demand. Such self-powered electromechanical devices are known as piezoelectric nanogenerators (PENGs). In this study, a piezo-ceramic element of hydrothermally synthesized ZnO flowers comprising built-in nanocuboids was supersonically sprayed with piezo-polymer polyvinylidene fluoride (PVDF) to fabricate ZnO-embedded PVDF films for flexible PENG devices. In the presence of ZnO, the catastrophic supersonic impact and shear flow transformed the nonpolar α-phase of PVDF into the polar β-phase. The combination of ZnO flowers with built-in nanocuboids and β-phase-rich PVDF can help enhance generated charges at interfacial sites under an applied force. The supersonically sprayed PVDF/ZnO composite exhibited a 32% increase in the β-phase compared to that exhibited by pure PVDF prior to supersonic coating. The effective piezoelectric coefficient values (d33*) of the pure PVDF and PVDF/ZnO composite films were 43 and 150 pm·V‐1, respectively; the corresponding open-circuit voltages were 1.2 and 25.5 V, respectively. These significant differences confirm the pivotal role of ZnO in increasing the β-phase within PVDF during supersonic spraying. The form of the externally applied force and frequency were varied to evaluate the electromechanical performance of PVDF/ZnO. The energy harvesting capability of the composite was demonstrated using 33 light-emitting diodes.

A controllable-valve buoy for high-efficiency wave energy conversion under a wide range of wave conditions

Heaving buoys are common devices for wave energy conversion. In recent years, many researchers have been devoted to improve their energy-absorbing capability by configuration optimization. Traditionally, the operation of wave energy converter (WEC) has to be interrupted for safety when waves become excessively strong. In this paper, in order to render the WEC able to work under a wide range of wave conditions so as to enhance the energy-harvesting capability and increase the total operation hours and total power production, a new type of buoy, controllable-valve buoy (CVB) is proposed. It is a hemisphere-cylinder combined buoy with a hollow channel covered by a controllable valve that can operate in two modes. In gentle sea states the valve is closed and the buoy absorbs wave energy to a large extent, while in rough sea states the valve is opened and the buoy is able to work and produce an acceptable power. The geometrical parameters of CVB are optimized via a systematic method combined with wave statistics of the target installation site. The radius and the draft of the optimized buoy are 4.8 m and 8 m, and it has a hollow channel with a radius of 2 m. Simulation results show that the optimized buoy demonstrates a good performance in both closed and opened mode.

A Self-Powered Asynchronous Image Sensor With TFS Operation

This article presents a self-powered image sensor with a novel pixel architecture with energy harvesting capabilities. Pixels are autonomous entities that can harvest or sense illumination independently. Pixels have a fully asynchronous operation and do not require to be scanned to read out their asynchronous output. The sensor was manufactured in UMC 180nm technology and tested. Their specifications are competitive against the art, offering fast operation, good balance between the energy consumed and harvested, and high-dynamic range operation. The article describes the sensor and pixel architectures in detail and provides experimental results. Sensor specifications are benchmarked against the art.

A Clockless Synergistic Hybrid Energy Harvesting Technique With Simultaneous Energy Injection and Sampling for Piezoelectric and Photovoltaic Energy

In this paper, a mutually synergistic hybrid energy harvesting (SHEH) circuit with both AC and DC energy harvesting capability is proposed. Within the proposed hybrid harvester, the vibration period of the piezoelectric transducer (PZT) is served as the switching signal for photovoltaic (PV) energy harvesting so that a dedicated clock generator is saved. Meanwhile, during the sampling phase, a small portion of the PV energy is injected into the PZT as an investment, which enhances the damping force and charge extraction of the PZT. Theoretically, the total synergistically extracted power from the proposed hybrid harvester is more than the sum of the power obtained from each transducer independently. The proposed SHEH circuit is fabricated with a 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS process. The buck-boost converter with zero-current switching control achieves a peak efficiency of 82.8%, and the maximum efficiency of piezoelectric energy harvesting can reach 4.5 times that of the full-bridge rectifier.

Intelligent Cubic-Designed Piezoelectric Node (iCUPE) with Simultaneous Sensing and Energy Harvesting Ability toward Self-Sustained Artificial Intelligence of Things (AIoT)

The evolution of artificial intelligence of things (AIoT) drastically facilitates the development of a smart city via comprehensive perception and seamless communication. As a foundation, various AIoT nodes are experiencing low integration and poor sustainability issues. Herein, a cubic-designed intelligent piezoelectric AIoT node iCUPE is presented, which integrates a high-performance energy harvesting and self-powered sensing module via a micromachined lead zirconate titanate (PZT) thick-film-based high-frequency (HF)-piezoelectric generator (PEG) and poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) nanofiber thin-film-based low-frequency (LF)-PEGs, respectively. The LF-PEG and HF-PEG with specific frequency up-conversion (FUC) mechanism ensures continuous power supply over a wide range of 10-46 Hz, with a record high power density of 17 mW/cm3 at 1 g acceleration. The cubic design allows for orthogonal placement of the three FUC-PEGs to ensure a wide range of response to vibrational energy sources from different directions. The self-powered triaxial piezoelectric sensor (TPS) combined with machine learning (ML) assisted three orthogonal piezoelectric sensing units by using three LF-PEGs to achieve high-precision multifunctional vibration recognition with resolutions of 0.01 g, 0.01 Hz, and 2° for acceleration, frequency, and tilting angle, respectively, providing a high recognition accuracy of 98%-100%. This work proves the feasibility of developing a ML-based intelligent sensor for accelerometer and gyroscope functions at resonant frequencies. The proposed sustainable iCUPE is highly scalable to explore multifunctional sensing and energy harvesting capabilities under diverse environments, which is essential for AIoT implementation.

Energy Harvesting and Task-Aware Multi-Robot Task Allocation in Robotic Wireless Sensor Networks

In this work, we investigate an energy-aware multi-robot task-allocation (MRTA) problem in a cluster of the robot network that consists of a base station and several clusters of energy-harvesting (EH) robots. It is assumed that there are M+1 robots in the cluster and M tasks exist in each round. In the cluster, a robot is elected as the cluster head, which assigns one task to each robot in that round. Its responsibility (or task) is to collect the resultant data from the remaining M robots to aggregate and transmit directly to the BS. This paper aims to allocate the M tasks to the remaining M robots optimally or near optimally by considering the distance to be traveled by each node, the energy required for executing each task, the battery level at each node, and the energy-harvesting capabilities of the nodes. Then, this work presents three algorithms: Classical MRTA Approach, Task-aware MRTA Approach, EH and Task-aware MRTA Approach. The performances of the proposed MRTA algorithms are evaluated under both independent and identically distributed (i.i.d.) and Markovian energy-harvesting processes for different scenarios with five robots and 10 robots (with the same number of tasks). EH and Task-aware MRTA Approach shows the best performance among all MRTA approaches by keeping up to 100% more energy in the battery than the Classical MRTA Approach and keeping up to 20% more energy in the battery than the Task-aware MRTA Approach.

Investigation of Energy Harvesting Capabilities of Metglas 2605SA1

In the framework of electromechanical energy conversion devices for vibrational energy harvesting, magnetostrictive materials are an attractive alternative solution to the brittleness of piezoelectric materials. Electromagnetic systems have low voltage output at a low frequency while magnetostrictive materials are suitable for a larger frequency bandwidth. In this work, a special experimental emphasis is placed on Fe80Si9B11 (also known as Metglas 2605SA1) alloy. The ultimate energy conversion abilities are investigated by performing experimental Ericsson cycles as well as through theoretical predictions using a dedicated model for the magnetic curves at the material scale. Typical output magnetic energy densities ranged between 0.1 and 1 mJ/cm3/cycle under moderate stress (&lt;100 MPa) and magnetic excitation (up to 4 kA/m). Apart from its energy conversion abilities, Metglas 2605SA1 also features attractive characteristics for realistic applications in microgenerators, such as a low price, which is an important advantage for the mass production and cost-effectiveness of the harvester. Furthermore, its soft magnetic property reduces the need for high magnetic fields and yields a well-adapted solution from a system point of view. It is therefore shown that this material is a suitable conversion material according to the available stress and magnetic excitation magnitudes, in addition to economic considerations.

Improved drift-free P&amp;O MPPT method to enhance energy harvesting capability for dynamic operating conditions of fuel cells

Improved drift-free P&amp;O MPPT method to enhance energy harvesting capability for dynamic operating conditions of fuel cells

Performance of SWIPT-Enabled FD TWR Network With Hardware Impairments and Imperfect CSI

Cooperative communication with energy harvesting capability increases network coverage and provides a green and sustainable solution for future wireless technologies. In this article, we analyze the performance of a two-way relay network, where bidirectional information exchange between two nodes takes place via simultaneous wireless information and power transfer-enabled relay node, operating in full-duplex (FD) mode over generalized Nakagami- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$m$</tex-math></inline-formula> fading channels. Different nonlinear power amplifier (NLPA) models, such as solid-state power amplifier, traveling wave tube amplifier, and soft envelope limiter, are considered at the relay node. The effect of practical constraints, such as imperfect channel state information (CSI) and transceiver hardware impairments (HIs), is considered. Further, we consider the impact of residual self-interference (RSI) due to imperfect successive interference cancellation in the FD mode. For performance analysis, the closed-form expressions of outage probability (OP), asymptotic OP, system throughput, energy efficiency, ergodic capacity, and asymptotic ergodic capacity are derived. The diversity order of the considered network is evaluated. Further, the impact of imperfect CSI, NLPA, HIs, RSI, and other parameters are highlighted on the system performance. The performance of FD and half-duplex mode is also compared. Monte Carlo simulations confirm the accuracy of the derived closed-form expressions.

Enhancing Network Lifetime of Duty Cycle-Based WSN With Mobile Sink Using Ambient Energy Harvesting

In order to guarantee a successful data collection process in wireless sensor networks with mobile sinks (WSN-MS), two primary objectives must be reached: 1) enabling the mobile sink to retrieve the maximum amount of data and 2) making sure that the network operates as long as possible. The first problem has been solved previously by proposing an innovative solution HXMAC. To address the second problem, on which this paper focuses, ambient energy harvesting is used to continuously supply power to each sensor node. Thus, this paper's main contribution is to propose EH-HXMAC (HXMAC with energy harvesting), which is based on all these improvements: seamless handover, duty cycling optimization, and mainly energy harvesting capability. EH-HXMAC has been evaluated using Cooja Contiki simulator. Obtained results based on the evaluation of the proposal EH-HXMAC clearly show its suitability as a good solution to promote unlimited lifetime for WSN-MS.

Power Distribution of D2D Communications in Case of Energy Harvesting Capability over κ-μ Shadowed Fading Conditions

Device-to-device (D2D) communication will play a meaningful role in future wireless networks and standards, since it ensures ultra-low latency for communication among near devices. D2D transmissions can take place together with the actual cellular communications, so handling the interference is very important. In this paper, we consider a D2D couple operating in the uplink band in an underlaid mode, and, using the stochastic geometry, we propose a cumulative distribution function (CDF) of the D2D transmit power under κ-μ shadowed fading. Then, we derive some special cases for some fading channels, such as Nakagami and Rayleigh environments, and for the interference-limited scenario. Moreover, we propose a radio frequency energy harvesting, where the D2D users can harvests ambient RF energy from cellular users. Finally, the analytical results are validated via simulation.