Energy Harvesting Protocol Research Articles

Performance analysis of energy harvesting‐enabled relay networks in κ‐μ fading channels

AbstractIn this paper, we investigate the performance of an energy harvesting (EH)‐enabled multiple relay network operating over generalized ‐ fading channels. Our approach involves utilizing a partial relay selection strategy and employing an amplify and forward relay protocol for efficient EH from RF signals. Additionally, we integrate a selection combining scheme at the receiver to combine both direct and relaying path signals. In our research, we first obtain the exact closed‐form expression of the cumulative distribution function (CDF) for the system under investigation. Subsequently, we derive expressions for the outage probability (OP) and the moment generating function (MGF) using the derived CDF expression. Furthermore, with the assistance of a CDF‐based approach, we derive closed‐form expressions for the average symbol error rate (ASER) for coherent quadrature amplitude modulation (QAM) schemes, including rectangular QAM (RQAM) and hexagonal QAM (HQAM). We also analyze the ASER expression for non‐coherent frequency shift keying (NCFSK), leveraging the derived MGF expression. To gain valuable insights into the performance of EH‐enabled multiple relay networks, we assess the asymptotic expression of the OP. The outcomes indicate how the behavior of the system is affected by various factors such as time switching ratio, channel fading components, number of relays, and the distance between nodes. To corroborate the accuracy of the analytical findings, Monte Carlo simulations are executed.

Adaptive Data Transmission Protocols for Energy Harvesting WSNs Used in Agriculture

Energy consumption is a major concern in wireless sensor networks (WSNs) as it affects the lifespan of sensor nodes. Battery-based WSNs have a short operating period, which makes them impractical for real-time applications, for instance in agriculture. Energy harvesting and suitable medium access control (MAC) protocols have been used to extend the lifetime of nodes. Receiver-initiated protocols have been proved to be the best solution for energy harvesting WSNs. However, they suffer from a key disadvantage, i.e. an increase in collision rate. These collisions need to be reduced using a multi-layer protocol structure. In such a context, a new solar-based hybrid MAC (SHMAC) protocol relying on receiver-initiation and characterized by a multi-layer structure is proposed. It is an adaptive protocol capable of adapting to changing weather conditions. The nodes with a high energy harvesting rate have a higher level of residual energy and are active for longer time periods compared with those with low energy harvesting characteristics. The proposed work has shown improvements in two major MAC layer parameters, i.e. collision rate and energy neutrality operation ratio (ENO).

Quasi-Consensus Control for Stochastic Multiagent Systems: When Energy Harvesting Constraints Meet Multimodal FDI Attacks.

In this article, the quasi-consensus control problem is investigated for a class of stochastic nonlinear time-varying multiagent systems (MASs). The innovation points of this research can be highlighted as follows: first of all, the dynamics of the plant are stochastic, nonlinear, and time varying, which resembles the natural systems in practice closely. Meanwhile, an energy harvesting protocol is put forward to collect adequate energy from the external environment. Second, as a generalization of the existing result, the ultimate control objective is quasi-consensus in a probabilistic sense, that is, designing a distributed control protocol in order that the probability of centering the allowable region for the states of each agent is larger than some predetermined values. Third, the MASs are subject to false data-injection (FDI) attacks, and a more general multimodal FDI model is proposed. On the basis of the probabilistic-constrained analysis technique and the recursive linear matrix inequalities (RLMIs), sufficient conditions are provided to guarantee the probabilistic quasi-consensus property. To derive the controller gains, an optimal probabilistic-constrained algorithm is designed by solving a convex optimization problem. Finally, two examples are provided to substantiate the validity of the proposed framework.

Uplink and downlink of energy harvesting NOMA system: performance analysis

ABSTRACT In this paper, we consider an uplink non-orthogonal multiple access (NOMA) for energy harvesting at the base station or access point in the wireless system. By exploiting energy enough, a base station or access point can serve many users at the downlink. The fixed power allocation factors are adopted, and the power splitting energy harvesting protocol brings many benefits to both the uplink and downlink of a wireless system. The closed-form expressions of outage probability are investigated and examined in a group of two users. Moreover, the optimal outage probability for two users is shown numerically. Finally, Monte Carlo simulations are presented to further support the validity of our framework and findings.

An optimised resource allocation scheme based on NOMA-SWIPT in cooperative network

ABSTRACT A cooperative network could improve energy efficiency by combining non-orthogonal multiple access (NOMA) with simultaneous wireless information and power transfer (SWIPT). This work proposes a novel model for optimal resource allocation for specified users through combined time switching and power splitting protocol. The system uses an amplified and forward-based energy harvesting protocol to broadcast the data in the Nakagami-m fading channel. An algorithm that provides the power coefficients for all NOMA users as a Levy Aquila optimiser is exploited to maximise the signal-to-noise ratio for far and near users. Further, the parameters of combined time switching and power splitting are brought by a game theoretic approach, which supports better energy harvesting in relay nodes with improved energy efficiency and high outage probability. The simulated results show that the employed scheme’s energy efficiency has increased by 11.3%, improved from the GS-Dinkelbach algorithm.

Power allocation optimization for hybrid information and energy transfer with massive MIMO downlink

AbstractThis paper investigates the power allocation in a massive multiple‐input multiple‐output (MIMO) downlink system, where the base station (BS) simultaneously transmits information and energy to information terminals and energy terminals without resorting to any wireless energy harvesting (EH) protocol, respectively. First, with respect to this system, the closed‐form expressions of achievable rate and harvested energy are, respectively, derived for Rayleigh fading channels. Then, from these expressions, three optimization problems are formulated based on quality‐of‐service (QoS) requirements, with the purposes of maximizing achievable sum rate, harvested sum energy and joint QoS requirements, respectively. The optimization problem of maximizing achievable sum rate is transformed into a sequence of geometric programmings (GPs), which can be solved efficiently with standard convex optimization tools. The optimization problem of maximizing harvested sum energy is proved to be solvable as a linear program. The optimization problem of maximizing joint QoS requirements is shown to be a multi‐objective optimization problem (MOOP) and solved by a one‐dimensional search based on GP. Finally, numerical results manifest that the proposed power allocation algorithms can provide good system performances of achievable sum rate and harvested sum energy, and jointly guarantee QoS fairness in terms of achievable rate and harvested energy.

An efficient hybrid energy harvesting protocol for cooperative NOMA systems: Error and outage performance

Cooperative non-orthogonal multiple access (CNOMA) has been recently adapted with energy harvesting (EH) to increase energy efficiency and extend the lifetime of energy-constrained wireless networks. In EH, two protocols are usually used for CNOMA, namely, power splitting (PS) and time switching (TS). In order to improve the existing EH protocols, this paper investigates a hybrid EH protocol-assisted CNOMA, which is a combination of the two aforementioned main existing EH protocols. The end-to-end bit error rate (BER) and outage probability (OP) expressions of users in our scheme are derived over Nakagami-m fading channels. For the sake of comparison and to highlight the achievable gains, the performance of the hybrid EH (HEH) protocol is compared with the benchmark schemes (i.e., existing EH protocols and no-EH). Based on extensive simulations, it is shown that the analytical results match perfectly with simulations which demonstrates the correctness of the derivations. Numerical results clearly indicate the superiority of the proposed scheme over the existing classical benchmarks. In addition, we discuss the optimum value of EH factors to minimize the error and outage in the proposed scheme and show that an optimum value can be obtained according to channel parameters.

Throughput Maximization for the Full-Duplex Two-Way Relay System with Energy Harvesting

The full-duplex technique can improve the transmission capacity of the communication systems, and energy harvesting (EH) is a promising operation to prolong the lifespan of a wireless node by utilizing the radio-frequency signals. In this paper, the throughput performance of a full-duplex two-way energy EH capable relay system is investigated. In particular, a practical EH protocol, named the time-switching-based relaying (TSR) protocol, is used for EH and the decode-and-forward (DF) policy for information transmission. The outage probability is successfully obtained, and the corresponding system throughput for TSR protocol can be derived by it. The derived throughput is a function of different system parameters, including the time-switching (TS) ratio, power allocation ratio, and the length of the communication time slot. Meanwhile, the throughput is used to characterize a joint time and power allocation scheme for the system, and we aim to find the optimal time and power allocation to achieve the optimal throughput. Due to the existence of three variables and the integral form of throughput expression, an optimization for the throughput is difficult. However, a modified simulated annealing-based search (SABS) algorithm can be used to optimize the throughput. The modified SABS algorithm overcomes being highly impacted by the initial point, and derives the optimal solution fast. Simulation results show that the analytical throughput expression is related with the TS ratio, power allocation ratio, and the length of the communication time slot. The analytical curve of the throughput matches with the simulated one well, which shows that the obtained analytical system throughput for the TSR protocol is valid. Meanwhile, the proposed modified SABS algorithm could be used to derive accurate throughput when SNR is higher than 10 dB.

A new energy harvesting scheme for multi-relay cooperative networks

Wireless networks have gone through unprecedented changes in the last decade owing to the rise in the number of users. Radio frequency (RF) energy harvesting (EH) (termed as RF-EH) can be a potential solution to encounter the energy constraints in the next generation wireless devices. In this study, we have proposed a new RF-EH technique from an RF source which was, to the best of our knowledge, not considered useful in any previous works. We have investigated the performance of an RF-EH cooperative multi-relay network by benefiting from the transmitted signal of the best relay (Rb) to the destination. In the most common RF-EH cooperative multiple relaying networks, only the relays harvest energy from the signal of source to power up themselves. However, in the proposed RF-EH technique, both the signals of source and Rb are exploited to harvest energy. In the proposed scheme, each of the relays harvests energy from the transmitted signal by source during phase-1, whereas the relays other than the Rb also harvest energy from the transmitted signal of Rb to destination during phase-2. Additionally, we have investigated our proposed scheme for both time-switching and power-splitting receiver architectures. Finally, from the simulation results, an increase in the system throughput and better outage performance is observed in the proposed scheme as compared to the conventional EH protocol in which EH is performed merely from the signal of source.

Outage and error performance analysis of dual hop hybrid RF-VLC system with wireless energy harvesting

The presented paper, investigates a dual hop hybrid radio frequency-visible light communication (RF-VLC) system with wireless energy harvesting at the relay. The information signal is transmitted via RF channel from the source (S) (located at some distant location) towards the destination (D). We assumed that there is no direct connectivity between S and D, thus a decode and forward relay (R) is used as an intermediate node between S and D. The source transmits the information signal towards the relay via RF channel. The received information signal at the relay is processed and converted into corresponding optical signal. The optical information signal is then forwarded to the destination. Parallelly, the relay employs the power splitting relaying (PSR) protocol with harvest-then cooperate (HTC) protocol for energy harvesting. The harvested energy is utilized to forward the optical information signal from relay to the user at the destination located inside a building’s room via VLC channel. We assumed that the RF and the VLC channels are modelled by generalized-K fading distribution and lambertian emission model respectively. The statistical characteristics are derived for the instantaneous signal to noise ratio of the individual channels using PSR protocol. Further, these statistics are used to derive the accurate closed form expressions for end to end outage probability and average bit error rate. Moreover, with the help of numerical results, end to end performance of the hybrid RF-VLC system under the influence of various system parameters such as shadowing parameters, power splitting factor, field of view angle of the detector and the distance between the source and the relay is analysed and verified.

Performance of SWIPT in Cooperative Networks With Direct Link and Nonlinear Energy Harvesting at the Battery-Assisted Relay

This paper investigates the performance of time-switching (TS) and power-splitting (PS) energy harvesting (EH) protocols in a two-hop cooperative network with a battery-assisted EH relay. Assuming the presence of the direct link and optimal combining at the destination, and practical nonlinear model for EH, expressions are derived for throughput with selective decode-and-forward (DF) relaying with the direct link (SDFDL) as well incremental relaying (IR). Augmenting the harvested energy with a small amount of battery energy significantly enhances the throughput. Combining direct and relayed signals significantly enhances throughput and decreases the energy consumption at the battery for any desired throughput as compared to the case when no direct link (NDL) from source to destination is used. The IR scheme achieves the highest throughput with very small energy consumption. We demonstrate that, unlike linear EH, the use of nonlinear EH results in loss of diversity, which makes use of the direct link even very important. Also, the use of the linear EH model gives unrealistically low energy consumption figures for any target throughput, making use of nonlinear EH models important. We elaborate on the choice of EH parameters and target rate on throughput and battery energy consumption. Monte Carlo simulations confirm the accuracy of the derived expressions.

A 2.4-GHz LoRa-Based Protocol for Communication and Energy Harvesting on Industry Machines

The fourth industrial revolution is paving the way for Industrial Internet of Things applications where large number of wireless nodes, equipped with sensors and actuators, monitor the production cycle of industrial goods. This paper proposes and analyses LoRaIN, a network architecture and MAC-layer protocol thought for on-demand monitoring of industrial machines. Our proprietary system is an energy-efficient, reliable and scalable solution, where the protocol is built on top of LoRa at 2.4 GHz. Indeed, the low-power characteristics of LoRa allow to reduce energy consumption, while Wireless Power Transfer is used to recharge batteries, avoiding periodic battery replacement. High reliability is obtained through the joint use of Frequency and Time Division Multiple Access. A dynamic LoRaIN scheduler manages the communication and recharging phases depending on the tasks assigned to the nodes, as well as the number of monitoring devices. Performance is measured in terms of network throughput, energy consumption and latency. Results demonstrate that the proposed solution is suitable for monitoring applications of industry machines.

An Optimal Balanced Energy Harvesting Algorithm for Maximizing Two-Way Relaying D2D Communication Data Rate

Combining energy harvesting (EH) and device-to-device (D2D) communication underlaying 5G cellular networks is a very promising direction to improve both energy and spectral efficiencies. Unlike conventional relay-aided D2D communication that assumes one-way relaying (OWR) protocols, this paper proposes a two-way relaying (TWR) model. It aims to maximize the TWR D2D link rate that shares the uplink (UL) resources of the conventional cellular user (CU) considering the quality of service (QoS) constraints of all users. Besides, the relays are considered to harvest renewable energy (RE) from the ambient environment by relying on an attached solar panel. Also, they can harvest radio frequency (RF) energy from the received signal based on the power splitting (PS) EH protocol. Assuming that the UL resource allocation (RA) is already performed, the paper’s objective is to jointly optimize the transmission power of all users in addition to the PS factor of relays based on the well-known meta-heuristic algorithm particle swarm optimization (PSO). Also, the best relay is selected by relying on the delimited area (DA) mechanism and the balanced residual energy (BRE) leading to TWR D2D link rate maximization and better energy efficiency (EE). The performance of the proposed algorithm is investigated through the results as well as comparing its performance to two of the most recent relay-aided D2D algorithms.

Performance limits of wireless powered cooperative NOMA over generalized fading

AbstractThe non‐orthogonal multiple access (NOMA) technique is a prospective solution to support the massive connectivity of an ever‐increasing number of wirelessly connected devices and address the spectrum scarcity issue. In this article, the outage probability and ergodic capacity of a two‐hop cooperative NOMA network with an energy‐limited relaying node are quantified over a generalizedstatistical model. The relay acts in an amplify‐and‐forward mode and performs energy harvesting (EH) using the time‐switching and power splitting relaying protocols. Moreover, the impact of hardware impairments (HIs) is incorporated into the performance evaluation. The obtained results prove the importance of HIs and allow one to evaluate the outage probability and ergodic capacity over various statistical models and system parameters. Finally, the results suggest that the optimal performance at a specific scenario depends on the combination of multiple factors, such as channel conditions, HI level, transmit power, and EH protocol.

Computational investigation of ultrasound induced electricity generation via a triboelectric nanogenerator

The efficient conversion of ultrasound into electrical energy remains a highly desirable wireless powering solution, with potentially profound ramifications in energy transfer across virtually all industrial fields, especially for implantable medical devices. Triboelectric nanogenerators have been shown to effectively carry out ultrasound energy transduction, though efficiency remains poor. Here, we devise a computational model to investigate the optimal triboelectric nanogenerator irradiation conditions, including frequency, probe distance, size, and design, as represented by irradiated triboelectric surface area displacement. Our investigation may set the foundations for the establishment of a standardized protocol for efficient ultrasound mechanical energy harvesting. This holds considerable significance and could be paramount in designing an ever-growing number of applicative solutions in wireless energy transfer, providing a scalable, cost effective and time saving solution in the development of implantable medical devices.

Two Energy Harvesting Protocols for SWIPT at UAVs in Cooperative Relaying Networks of IoT Systems

Two Energy Harvesting Protocols for SWIPT at UAVs in Cooperative Relaying Networks of IoT Systems

Joint spectral efficiency optimization of uplink and downlink for massive MIMO-enabled wireless energy harvesting systems

This paper investigated the spectral efficiency (SE) in massive multiple-input multiple-output systems, where all terminals have no fixed power supply and thus need to replenish energy via the received signals from the base station. The hybrid wireless energy harvesting (EH) protocol is applied for each terminal, which can switch to either existing time-switching (TS) protocol or power-splitting (PS) protocol. Based on the hybrid wireless EH protocol, a general system model is developed, which can switch to either only uplink data transmission or only downlink data transmission. As a result, a general analytical framework is formulated. Then, closed-form lower bound expressions on SE for each terminal are obtained on the uplink and downlink, respectively. According to these expressions, the joint SE of uplink and downlink maximization problem is designed with some practical constraints. As the designed optimization problem is non-linear and non-convex, it is hard to solve directly. To provide a solution, an iteration algorithm is proposed by utilizing one-dimensional search technique and successive approximation method based on geometric program. Additionally, the convergence and complexity of the proposed algorithm are discussed as well. Finally, the feasibility of the proposed algorithm is analyzed by simulations. Numerical results manifest that the proposed algorithm can provide good SE by optimizing relevant system parameters, and the system model can help to discuss the TS, PS or hybrid protocol for only uplink data transmission, only downlink data transmission or joint data transmission of uplink and downlink in the considered system.

Performance Analysis of Hybrid Cellular and Bidirectional Device-to-Device Cooperative NOMA Communication Systems

In this paper, we consider a coexisting network of cellular transmission and device-to-device (D2D) communication, in which two users need to receive downlink signals from base station (BS), meanwhile, they want to exchange information with each other. For such a network, a hybrid cellular and bidirectional D2D cooperative non-orthogonal multiple access (HCBD-CNOMA) scheme is proposed. To characterize the performance of our proposed scheme, we derive the closed-form ergodic rate and outage probability by considering both perfect and imperfect successive interference cancellation (SIC). To acquire more insights, their corresponding asymptotic expressions are obtained as well. Moreover, considering the fact that the nodes in Internet of Things (IoT) network are usually powered by battery and thus their power is limited, we further consider the scenario that two users are energy-constraint. In this scenario, users first need to harvest energy from the transmission of BS based on time splitting (TS) or power splitting (PS) energy harvesting (EH) protocol and then use these energy to accomplish subsequent communications. Similarly, the exact ergodic rate and outage probability as well as their asymptotic expressions for this scenario are analyzed. Simulation results validate the accuracy of analytical results, and reveal the performance gain of our schemes over the benchmark schemes.

Threshold-based Wireless-based NOMA Systems over Log-Normal Channels: Ergodic Outage Probability of Joint Time Allocation and Power Splitting Schemes

Due to the development of state-of-the-art fifth-generation communication (5G) and Internet-of-Things (IoT), the demands for capacity and throughput of wireless networks have increased significantly. As a promising solution for this, a radio access technique, namely, non-orthogonal multiple access (NOMA) has been investigated. Particularly, in this paper, we analyse the system performance of a joint time allocation and power splitting (JTAPS) protocol for NOMA-based energy harvesting (EH) wireless networks over indoor scenarios, which we modelled with log-normal fading channels. Accordingly, for the performance analysis of such networks, the analytical expression of a metric so-called “ergodic outage probability” was derived. Then, thanks to Monte Carlo simulations done in Matlab, we are able to see how different EH power splitting (PS) and EH time switching (TS) factors influence the ergodic outage probability. Last, but not least, we plot the simulation results along with the theoretical results for comparison studies.

Enabling Co-Existence of Cognitive Sensor Nodes With Energy Harvesting in Body Area Networks

In this article, we investigate a spectral and energy-efficient wireless body area network (WBAN) for smart healthcare applications. Herein, we primarily focus on improving the spectrum utilization by intelligently sharing spectrum resources through cognitive radio (CR) technology, allowing various sensor nodes in the underlying network to co-exist without compromising on their quality-of-service (QoS). We prioritize the sensor nodes based on their applications (medical/non-medical) and thereby categorize them into primary and secondary users to implement an on-body CR-WBAN. Furthermore, two energy harvesting (EH) protocols namely time-switching cooperation (TSC) and power-splitting cooperation (PSC) are employed to facilitate the secondary node cooperation with the primary network in return for spectrum access. For both the primary and secondary networks, we derive useful expressions for the outage probability. To provide more insights into the proposed CR-WBAN, the throughput and energy efficiency performances assuming a delay-limited scenario are investigated. The impact of key parameters are demonstrated to provide guidelines for the practical design of spectral and energy-efficient WBANs. The accuracy of our proposed analytical framework is verified through Monte Carlo simulations.