Energy Harvesting Relay Research Articles

Trajectory design of UAV-aided energy-harvesting relay networks in the terahertz band

Trajectory design of UAV-aided energy-harvesting relay networks in the terahertz band

UAV aided NOMA relaying with energy harvesting architecture: Performance analysis

In this work, we consider a dual hop Non Orthogonal Miltiple Access (NOMA) based communication network between Source S and two destination users UA , UB which is aided by an Unmanned Aerial Vehicle (UAV) relay R. The energy constrained UAV relay harvests energy from signal transmitted by the source through Power Splitting (PS) and further transmits the signal using Amplify and Forward (AF) protocol to the destination users through NOMA. For the proposed network, we derive analytical expressions for outage probability and ergodic capacity. The impact of parameters like PS ratio and UAV altitude is studied on the overall system performance. Further, the performance of the proposed system is also compared with Orthogonal Multiple Access (OMA) scheme. The results obtained show that the energy harvesting capacity of UAV is significantly affected under Linear and Non Linear EH models. The numerical analysis done is verified through Monte Carlo Simulations.

Energy-harvesting recursive filtering for delayed systems with amplify-and-forward relays: Cooperative communication manner

The recursive filtering problem is explored for a class of nonlinear time-delayed systems with amplify-and-forward (AF) relay and energy-harvesting (EH) technology. In order to enhance the signal quality of the remote transmission in wireless communication, the relay under the AF protocol is introduced that posing the merits of low complexity, less energy consumption and fast transmission rate. Meanwhile, to further alleviate the fading and improve the robustness of the signals, the cooperative communication manner is employed, which is different from the commonly encountered two-hop one. In the cooperative communication, the maximal ratio combining (MRC) method is utilized to make sure that the signal-to-noise ratio of the combined output can reach theoretical maximum. In addition, in order to achieve sustainable power supply in harsh environments, the EH sensors and relays are deployed, which can collect energy from external environments with certain probabilities. The aim of this paper is to develop a proper filter so as to reduce the impacts caused by the channel fading and insufficient energy. Furthermore, a minimized upper bound of the filtering error covariance is gained through appropriately designing the filter parameters. Then, the exponential boundedness is analyzed with regard to filtering error. Finally, a numerical example is exhibited to test the validity of the proposed filtering scheme.

Outage of cooperative NOMA with an energy harvesting relay in an underlay cognitive radio network

SummaryThis paper analyzes the performance of a cooperative nonorthogonal multiple access (NOMA) in an underlay cognitive radio network aided by an energy harvesting relay. A secondary source transmits signal for two users, where a near user acts as a relay for the far user. The far user applies the selection combining (SC) approach on the signals which were relayed by the near user and received via direct path from the secondary source. We analytically derive the outage probability (OP) of each user separately, the overall system OP, and the throughput of the system. The impact of the power allocation coefficient of NOMA and energy harvesting parameters on outage is indicated. Further, the performance of the network is investigated with imperfection in successive interference cancellation (SIC), maximal ratio combining (MRC) at relay, and Nakagami‐m fading. The results derived analytically are supported by simulation in MATLAB.

On the Capacity of M-ary ASK Two-Hop Channel With Finite Battery Energy Harvesting Relay

On the Capacity of <i>M</i>-ary ASK Two-Hop Channel With Finite Battery Energy Harvesting Relay

Outage and ergodic capacity analysis of a full‐duplex energy‐harvesting cooperative non‐orthogonal multiple access network

SummaryThis paper considers a dual‐hop cooperative relay‐based communication with uplink (UL) and downlink (DL) non‐orthogonal multiple access (NOMA), where communication between sources to destinations takes place parallelly in the same frequency band over a Rayleigh fading channels. The energy harvesting (EH)‐based full‐duplex (FD) relay helps in forwarding the message from the source node to the destination node via superposition coding, thus calling it a multiple sources full‐duplex energy‐harvesting cooperative relay NOMA (MS‐FD‐EH‐CR‐NOMA) system. Early works focus on EH from one source node or a dedicated power station. In this article, the communication between sources and destinations occurs in two slots where first slot deals with energy harvesting while in second slot information transmission occurs. We studied the effect of imperfect successive interference cancellation (ipSIC) and residual self‐interference (RSI) in decoding the message at the relay and the destinations. We derived the closed‐form expressions for the outage probability of each pair and the system outage probability of the MS‐FD‐EH‐CR‐NOMA system. Next, we derive the closed‐form expressions of ergodic capacity under Rayleigh distributed fading channels. Further, numerical results are validated by its simulation results using Monte Carlo simulations in MATLAB. The results obtained through this work are a good step towards designing multiple source–destination communication using NOMA and EH relay.

On the Dilemma of Reliability or Security in Unmanned Aerial Vehicle Communications Assisted by Energy Harvesting Relaying

On the Dilemma of Reliability or Security in Unmanned Aerial Vehicle Communications Assisted by Energy Harvesting Relaying

Outage Analysis of Hybrid VLC/RF Networks With an Energy Harvesting Relay and Random Receiver Orientation

Outage Analysis of Hybrid VLC/RF Networks With an Energy Harvesting Relay and Random Receiver Orientation

Vehicular Communication Based on RIS-Assisted Source: RIS-Relay Versus Energy Harvesting Relay

Vehicular Communication Based on RIS-Assisted Source: RIS-Relay Versus Energy Harvesting Relay

Smart Energy Borrowing and Relaying in Wireless-Powered Networks: A Deep Reinforcement Learning Approach

Wireless energy harvesting (EH) communication has long been considered a sustainable networking solution. However, it has been limited in efficiency, which has been a major obstacle. Recently, strategies such as energy relaying and borrowing have been explored to overcome these difficulties and provide long-range wireless sensor connectivity. In this article, we examine the reliability of a wireless-powered communication network by maximizing the net bit rate. To accomplish our goal, we focus on enhancing the performance of hybrid access points and information sources by optimizing their transmit power. Additionally, we aim to maximize the use of harvested energy, by using energy-harvesting relays for both information transmission and energy relaying. However, this optimization problem is complex, as it involves non-convex variables and requires combinatorial relay selection indicator optimization for decode and forward (DF) relaying. To simplify this problem, we utilize the Markov decision process and deep reinforcement learning framework based on the deep deterministic policy gradient algorithm. This approach enables us to tackle this non-tractable problem, which conventional convex optimization techniques would have difficulty solving in complex problem environments. The proposed algorithm significantly improved the end-to-end net bit rate of the smart energy borrowing and relaying EH system by 13.22%, 27.57%, and 14.12% compared to the benchmark algorithm based on borrowing energy with an adaptive reward for Quadrature Phase Shift Keying, 8-PSK, and 16-Quadrature amplitude modulation schemes, respectively.

Outage Performance for NOMA-Based FSO-RF Systems With a Dual Energy Harvesting Mode

Energy harvesting (EH) is an effective approach that can not only extend the service life for those energy-constraint devices, but also reduce the carbon footprint for wireless communication. Unlike the commonly used single EH scheme adopted in existing works, in this considered free space optical-radio frequency (FSO-RF) system, a dual EH mode is considered, in which an EH relay is capable of harvesting energy from both the ambient RF signal in the environment and the direct-current component separated from the FSO signal simultaneously. In addition, in this considered system, a source node plans to communicate with two users equipped with multiple antennas via an EH relay on a non-orthogonal multiple access (NOMA) basis, and all the harvested energy of the relay is used to transmit the signal to both NOMA users. Moreover, assuming a selection-combining scheme is adopted at the user side, both the analytical and asymptotic expressions of outage probability for each NOMA user are presented, and the system performance with various atmospheric turbulence, detection technique, as well as pointing error is investigated. Finally, numerical results show that our proposed dual EH mode can lead to better outage performance than that with the single EH one.

Security-Reliability Analysis of AF Full-Duplex Relay Networks Using Self-Energy Recycling and Deep Neural Networks.

This paper investigates the security-reliability of simultaneous wireless information and power transfer (SWIPT)-assisted amplify-and-forward (AF) full-duplex (FD) relay networks. In practice, an AF-FD relay harvests energy from the source (S) using the power-splitting (PS) protocol. We propose an analysis of the related reliability and security by deriving closed-form formulas for outage probability (OP) and intercept probability (IP). The next contribution of this research is an asymptotic analysis of OP and IP, which was generated to obtain more insight into important system parameters. We validate the analytical formulas and analyze the impact on the key system parameters using Monte Carlo simulations. Finally, we propose a deep learning network (DNN) with minimal computation complexity and great accuracy for OP and IP predictions. The effects of the system's primary parameters on OP and IP are examined and described, along with the numerical data.

Impartial Cooperation in SWIPT-Assisted NOMA Systems With Random User Distribution

Impartial cooperation is considered in simultaneous wireless information and power transfer (SWIPT)-assisted downlink non-orthogonal multiple access (NOMA) systems with random user distribution. Unlike conventional SWIPT-assisted cooperative NOMA transmissions, we consider random user locations and investigate a transmission model in which both the near and far users of a NOMA system can serve as energy harvesting relays and forward information to each other. To assess the impact of user placement on the system performance, three user pairing schemes are designed. Closed-form expressions for the outage probability, diversity order, diversity-multiplexing trade-off (DMT), and system throughput are derived under different user location distributions, revealing that the novel SWIPT-assisted impartial cooperative NOMA improves these metrics of the near user, and does not degrade those of the far user, compared with the conventional schemes. Numerical results validate our analysis and confirm that our approach is more efficient in resource utilization, as compared to existing schemes.

Average AoI Minimization for Energy Harvesting Relay-Aided Status Update Network Using Deep Reinforcement Learning

A dual-hop status update system aided by energy-harvesting (EH) relays with finite data and energy buffers is studied in this work. To achieve timely status updates, the best relays should be selected to minimize the average age of information (AoI), which is a recently proposed metric to evaluate information freshness. The average AoI minimization can be formulated as a Markov decision process (MDP), but the state space for capturing channel and buffer evolution grows exponentially with the number of relays, leading to high solution complexity. We propose a relay selection (RS) scheme based on deep reinforcement learning (DRL) according to the instantaneous channel packet freshness and buffer information of each relay. Simulation results show a significant improvement of the proposed DRL-based RS scheme over state-of-art approaches.

An enhanced energy efficient protocol for large-scale IoT-based heterogeneous WSNs

There is increasing attention, recently, to optimizing energy consumption in IoT-based large-scale networks. Extending the lifetime of battery-powered nodes is a key challenge in such systems and their various application scenarios. This paper proposes a new zone-based and event-driven protocol for saving energy in large-scale heterogeneous WSNs called TESEES (Threshold Enabled Scalable and Energy Efficient Scheme). The proposed protocol is designed to support network scenarios deploying higher levels of heterogeneity with more than three types of sensor nodes (i.e., four, five, and more). TESEES is a reactive version of the proactive SEES protocol, in which we leverage a novel state-of-the-art thresholding model on the zone-based hierarchical deployments of heterogeneous nodes to regulate the data reporting process, avoiding unnecessary frequent data transmission and reducing the amount of energy dissipation of the sensing nodes and the entire system. With this model, we present a general technique for formulating distinct thresholds for network nodes in each established zone. This mechanism allows for individually configuring the nodes with transmission settings tailored to their respective roles, independent of the heterogeneity levels, total node count, or initial energy. This approach ensures that each node operates optimally within the network. In addition, we present an improved hybrid TMCCT (Threshold-based Minimum Cost Cross-layer Transmission) algorithm that operates at the node level and ensures effective data transmission control by considering current sensor values, heterogeneous event thresholds, and previous data records. Instead of periodical data transmission, this hybridization mechanism, integrated with a grid of energy-harvesting relay nodes, keeps the zone member nodes in the energy-saving mode for maximum time and allows for reactive data transmission only when necessary. This results in a reduced data-reporting frequency, less traffic load, minimized energy consumption, and thus a greater extension of the network’s lifetime. Moreover, unlike the traditional cluster-head election in the weighted probability-based protocols, TESEES relies on an efficient mechanism for zone aggregators’ election that runs at the zone level in multiple stages and employs various static and dynamic parameters based on their generated weights of importance. This leads to selecting the best candidate nodes for the aggregation task and, hence, fairly rotating the role among the zones’ alive nodes. The simulation results show significant improvements in the total energy saving, the lifetime extension, and the transmitted data reduction, reaching 29%, 68%, and 26% respectively, compared to the traditional SEES protocol. Also, the average energy consumption per single round has decreased by 36%.

Securing Multiuser Communications via an Energy Harvesting Node: Jammer or Relay?

In this paper, we study the secure communication problem of a wireless multiuser network consisting of a base station (BS), multiple users, and an energy harvesting (EH) node in the face of an eavesdropper. We focus on the question that which role the EH node plays, as a friendly jammer or as a cooperative decode-and-forward (DF) relay. Accordingly, we propose two EH node aided multiuser scheduling schemes to help the secure communications between BS and multiple users, i.e., the EH jammer aided transmission (EHJT) scheme where the EH node acts as a friendly jammer and the EH relay aided transmission (EHRT) scheme where the EH node acts as a cooperative DF relay. For comparison purposes, the direct transmission (DT) scheme is also presented. We analyze the security-reliability trade-off (SRT) performance of the proposed EHJT and EHRT schemes as well as the DT scheme in terms of deriving their exact and asymptotic expressions of outage and intercept probabilities. Additionally, we propose an iterative algorithm based on the golden search to determine the optimal time allocation factor (OTAF) for the sake of minimizing the sum of outage and intercept probabilities for the proposed EHJT and EHRT schemes. Numerical results show that the EH node can improve the SRT performance of the multiuser network more significantly as a friendly jammer than as a cooperative DF relay. It is also shown that the best SRT performance of the EHJT and EHRT schemes can be achieved by adjusting the signal-to-noise ratio (SNR) and time allocation factor.

Simulating the physical layer security performance of underlay cognitive energy-harvesting relay radio networks

This article analyzes the security performance of underlay cognitive energy-harvesting relay radio networks (UCEHRRN) through the Monter-Carlo simulation results. The results clarify the influence of critical operating parameters on the security performance of the system. Furthermore, the security capabilities of UCEHRRN have been compared with those of the live transmission system. Moreover, many results show that the security performance of the system is significantly improved. Analysis of the results also shows that UCEHRRN is especially effective when the direct transmission system cannot achieve security due to objective reasons such as path loss, severe fading, and shadowing.

Cooperative encryption over backscatter: Secure green communication for two-way energy harvesting relay networks

This paper focuses on the design of a novel cooperative jamming strategy and resource allocation scheme in two-way energy harvesting (EH) relay networks. For solving the security vulnerability challenges, a backscatter jamming strategy is proposed by leveraging the information signals as the carrier, which can degrade the eavesdropping link without extra energy consumption, delay and strict synchronization requirement. Based on the above design, we formulate the secure energy efficiency (SEE) maximization problem by jointly optimizing the transmission powers of two sources, two different power splitting (PS) factors and time allocation factor. Although the resulting optimization problem is highly non-convex due to fractional objective function and multivariate coupling, an iterative algorithm is developed to convert the original problem into a tractable version and obtain the resource allocation solutions. Simulation results show that the achievable SEE of the proposed scheme is better than other conventional schemes.

Performance analysis of MRT/RAS scheme in dual-hop NOMA energy harvesting relay networks

This paper investigates the outage probability (OP) performance of multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) relaying networks. In the investigated network, a source simultaneously communicates multiple NOMA users with the assistance of an amplify-and-forward energy harvesting relay. We derive each user’s OP expression in closed form over the generic channel model Nakagami-m fading. Moreover, we carry out asymptotic analysis to have clear insights into the OP behavior in the high signal-to-noise ratio region. The theoretical analysis’s correctness is finally verified via Monte Carlo simulations. The results show that the OP performance improves with the increased number of antennas and enhancement in the channel conditions. Furthermore, the relay has to be near the source in order to have better OP performance. Moreover, each user has a different optimum power division ratio.

Impact of Fading Channel to Energy Harvesting Relay on Cooperative Communication Systems

Channel conditions strongly influence the performance of the wireless communication system. Fading is one of the main problems caused by signal propagation via various paths. Recently, cooperative communication systems have been extensively studied to overcome this problem. However, the power consumption in the system relaying information to the destination increases, shortening the network's life. Therefore, this paper analyzes the impact of three Raleigh and Rician fading channel scenarios on cooperative communication performance in which a relay uses energy harvesting based on power splitting (EH-PS). The three scenarios are Rayleigh-Rayleigh fading (I), Rician- Rayleigh fading (II), and Rician-Rician fading (III). Subsequently, the throughput performance and energy efficiency are evaluated based on the maximum power splitting (PS) ratio. The simulation results indicate that the PS ratio in scenario III is higher than in scenarios I and II. Thus, the Rician fading channel can accumulate more energy in the relay due to the line-of-sight path between the source and the relay. Hence, scenario III's throughput and energy efficiency are higher than the other scenarios. The energy efficiency for scenario III is 33.08% and 12.14% higher than scenarios I and II, respectively. Therefore, the EH-PS cooperative communication system with the Rician fading channels has the highest throughput and is promising for future 5G technology.