Self-energy Recycling Research Articles

Outage Probability Analysis for Relay-Aided Self-Energy Recycling Wireless Sensor Networks Over INID Rayleigh Fading Channels

Outage Probability Analysis for Relay-Aided Self-Energy Recycling Wireless Sensor Networks Over INID Rayleigh Fading Channels

Self-Energy Recycling in DF Full-Duplex Relay Network: Security-Reliability Analysis

Self-Energy Recycling in DF Full-Duplex Relay Network: Security-Reliability Analysis

Resource allocation for full-duplex MIMO relaying system with self-energy recycling

Resource allocation for full-duplex MIMO relaying system with self-energy recycling

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.

Efficient Battery Usage in Wireless-Powered Cell-Free Systems With Self-Energy Recycling

This paper investigates wireless-powered cell-free systems, in which the users send their uplink data signal while simultaneously harvesting energy from network nodes and user terminals – including the transmitting user terminal itself – by performing self-energy recycling. In this rather general setting, a closed-form lower bound of the amount of harvested energy and the achieved signal-to-interference-plus-noise ratio expressions are derived. Then, to improve the energy efficiency, we formulate the problem of minimizing the users' battery energy usage while satisfying minimum data rate requirements. Due to the non-convexity of the problem, a novel alternating optimization algorithm is proposed, and its proof of convergence is provided. Finally, numerical results show that the proposed method is more efficient than a state-of-art algorithm in terms of battery energy usage and outage rate.

Self-Energy Recycling for Low-Power Reliable Networks: Half-Duplex or Full-Duplex?

Self-energyrecycling (sER), which allows transmit energy reutilization, has emerged as a viable option for improving the energy efficiency (EE) in low-power Internet of Things networks. In this article, we investigate its benefits also in terms of reliability improvements and compare the performance of full-duplex (FD) and half-duplex (HD) schemes when using multiantenna techniques in a communication system. We analyze the tradeoffs when considering not only the energy spent on transmission but also the circuitry power consumption, thus making the analysis of much more practical interest. In addition to the well-known spectral efficiency improvements, results show that FD also outperforms HD in terms of reliability. We show that sER introduces not only benefits in EE matters but also some modifications on how to achieve maximum reliability fairness between uplink and downlink transmissions, which is the main goal in this article. In order to achieve this objective, we propose the use of a dynamic FD scheme where the small base station determines the optimal allocation of antennas for transmission and reception. We show the significant improvement gains of this strategy for the system outage probability when compared to the simple HD and FD schemes.

Wireless Powered Relay Networks: Rate Optimal and Power Consumption-Aware WPT/SWIPT

We focus on the rate-optimal design of Wireless Powered Relay Networks (WPRNs) and propose a new cooperative communication scheme. Our scheme employs multiple wireless powered Amplify and Forward (AF) relays and relay selection and combines Time Splitting (TS), with Antenna Switching (AS) and Self Energy Recycling (SER). It consists of an initial Wireless Power Transfer (WPT) subframe, followed by a cooperative transmission subframe, during which one antenna is used for Energy Harvesting (EH) and SER and the remaining ones are used for data reception and data forwarding. For this scheme, we present solutions to the problems of 1) rate-optimal beamforming (BF) design, 2) rate-optimal, joint Harvesting Antenna Selection (HAS), BF design, and WPT subframe duration determination. Our solutions build on a generic piecewise linear EH model, which allows us to closely approximate the characteristics of different non linear EH measurements and models, by selecting the number of piecewise linear components and their parameters. In addition, we consider a realistic power consumption model at the relays that accounts for both transmit and circuit power consumption. Moreover, our BF solution is optimal and requires solving a set of simple optimization problems, where the solution of each one of them can be found in a simple closed form. Thus, it is characterized by low implementation complexity, and avoids sophisticated iterative optimization methods. To the best of our knowledge, this work is the first one to introduce a scheme, which combines TS, AS, and SER principles and exploits realistic EH and power consumption models at the relays. Finally, we assess the performance of our scheme over fading channels and find that it outperforms existing solutions that use the same hardware.

Partial and Full Relay Selection Algorithms for AF Multi-Relay Full-Duplex Networks With Self-Energy Recycling in Non-Identically Distributed Fading Channels

Full-duplex communication offers enhanced spectral efficiency for relay deployment, but suffers from the inherent self-interference from the strong transmit signal coupling to the sensitive receive chain. In this article, we propose a self-energy recycling (S-ER) protocol for full-duplex multi-relay networks, in which the energy from self-interference is harvested back at the relay for future use. Furthermore, two amplify-and-forward (AF) relay selection algorithms, namely, partial relay selection (PRS) and full relay selection (FRS) are introduced to enhance the reliability of the proposed systems. For PRS, the best relay is selected based on just the knowledge of the channels from the source to all relays, while in FRS, the best relay is selected based on the end-to-end signal-to-noise ratio, which requires knowledge of all source-relay and relay-destination links. We provide a thorough analysis on the outage performance and the spectrum efficiency of the proposed algorithms in both cases: all channel gains are independently but non-identically distributed (i.n.d.) (case 1) or independently, identically distributed (i.i.d.) (case 2) Rayleigh random variables. It is shown that SER and FRS can significantly enhance the performance of FD networks and avoid the outage floor when the number of relays increases, while the outage probability (OP) in PRS case reaches an outage floor. In addition, the end-to-end signal-to-noise ratio in both cases can be minimized if an optimal power-splitting factor is selected. All analytical results are verified by Monte Carlo simulation.

Impact of Self-Energy Recycling and Cooperative Jamming on SWIPT-Based FD Relay Networks With Secrecy Constraints

This paper investigates the secrecy performance of a power splitting-based simultaneous wireless information and power transfer cooperative relay network in the presence of an eavesdropper. The relay is considered to operate in full-duplex (FD) mode to perform both energy harvesting and information decoding simultaneously. To accomplish that, the relay is assumed to employ two rechargeable batteries, which switch between power supplying mode and charging mode at each transmission block. We also assume that the self-interference inherent of the FD mode is not completely suppressed. Therefore, it is assumed that, after some stages of passive and active self-interference cancellation, there is still a residual self-interference (RSI). A portion of this RSI (remaining after passive cancellation) is recycled for energy harvesting. In order to improve the system secrecy performance, it is considered that the relay can split its transmit power to send the information signal and to emit a jamming signal to degrade the eavesdropper’s channel. The secrecy performance is evaluated in terms of the secrecy outage probability and the optimal secrecy throughput. Tight-approximate and asymptotic expressions are obtained for the secrecy outage probability, and the particle swarm optimization method is employed for addressing the secrecy throughput optimization problem. From numerical results, we show that the secrecy performance can be increased depending on the self-energy recycling channel condition. Finally, our derived expressions are validated via Monte Carlo simulations.

Energy Signal-Aided Secure Beamforming and Self-Energy Recycling in Full-Duplex Wireless-Powered Relay Networks

In this paper, the object of study is secure transmission and green energy transfer in full-duplex (FD) wireless-powered relay (WPR) secure systems, where an FD relay collects the power from radio-frequency signs and transmits the information in the face of multiple eavesdroppers. In order to improve the efficiency and safety of the contemporaneous wireless energy and information delivery, we propose a joint energy-signal- (ES-) aided secure beamforming and time-switch scheme under the self-power circulation protocol at the relay. The question formulated in this paper is to maximize the confidentiality rate according to energy restrictions at both the relay and energy receiver. As the question is non-salient and hard to resolve directly, we transform it into two sub-problems. For the first sub-problem, a two-level optimization technique is suggested to separately gain the optimal beamforming as well as the ES covariance. The extrinsic rank is a single-variable majorization question, which can be solved by single-dimensional (1D) examination. We attain an optimal solution to the inner level by a semi-definite relaxation (SDR) technique. For the second sub-problem, we again use 1D search to solve this problem. Moreover, we prove that SDR always exists as a level-1 optimal resolution. Mathematical outcomes show that the suggested plan can achieve a considerable gain of confidentiality rate by comparison with other benchmark plans.

Improving Physical Layer Security of Cooperative NOMA System with Wireless-Powered Full-Duplex Relaying

Non-orthogonal multiple access (NOMA) and wireless energy harvesting are two promising technologies for improving spectral efficiency and energy efficiency, respectively. In this paper, we study the physical layer security of a wireless-powered full-duplex (FD) relay-aided cooperative NOMA system. In particular, the source is wiretapped by an eavesdropper, and the FD relay assists the transmission from the source to a near user and a far user with self-energy recycling. To enhance the security performance of the system, we propose an artificial noise (AN)-aided cooperative transmission scheme, in which the relay emits a jamming signal to confuse the eavesdropper while receiving the signal from the source. For the proposed scheme, the ergodic secrecy sum rate (ESSR) is derived to characterize the secrecy performance and a lower bound of ESSR is obtained. Finally, numerical results verify the accuracy of the theoretical analysis of the proposed AN-aided secure transmission scheme. The superiority of the proposed scheme is also demonstrated since this scheme can achieve better secrecy performance, compared to the conventional cooperative NOMA scheme.

On the Performance of Full-Duplex Cooperative NOMA With Non-Linear EH

This paper studies a non-linear energy harvesting (EH) enabled full-duplex (FD) cooperative non-orthogonal multiple access (C-NOMA) system, where the near user acts as an FD relay to assist the transmission from BS to far user with power-splitting (PS) protocol. We derive the close-form expressions of outage probability in this considered system, and also give the asymptotic outage probability under high signal-to-noise ratio (SNR) regime. Additionally, we obtain the optimal power allocation parameter to minimize the outage probability, and discuss the impact of self-interference (SI) on outage performance. Moreover, it is observed from simulation results that the presence of SI improve the outage performance, which is caused by the so-called self-energy recycling.

Wireless Information and Power Transfer Using Full-Duplex Self-Energy Recycling Relays

Wireless Information and Power Transfer Using Full-Duplex Self-Energy Recycling Relays

Non-Time-Switching Full-Duplex Relay System with SWIPT and Self-Energy Recycling

Non-Time-Switching Full-Duplex Relay System with SWIPT and Self-Energy Recycling

Joint of full-duplex relay, non-linear energy harvesting and multiple access in performance improvement of cell-edge user in heterogeneous networks

To serve massive connections in heterogeneous networks with respect to higher energy efficiency, we focus on new paradigm in order to achieve multiple access and performance improvement at cell-edge area. The power domain based non-orthogonal multiple access is introduced to address such problem. In particular, this paper studies a self-energy relay together with full-duplex scheme to implement cooperative power domain based non-orthogonal multiple access in small-cell system of the heterogeneous networks. In such small-cell network, a nearby user can be employed as a decode-and-forward with self-energy recycling protocol to assist a far power domain based non-orthogonal multiple access user (cell-edge user). The relay harvests energy from dedicated energy signal sent by a base station, while it still reuses energy from loop self-interference signal. To characterize the performance of the proposed system with respect to where meets weak signal condition, numerous expressions of exact outage probability for far power domain based non-orthogonal multiple access user is derived. Several practical scenarios are performed in three different schemes related to how energy harvesting architecture can be achieved. Based on analytical results, the optimal throughput achieved by the cell-edge user in small-cell network can be observed. Numerical results are presented to validate the accuracy of the derived results.

Full-duplex wireless information and power transfer in two-way relaying networks with self-energy recycling

In this paper, we consider full-duplex (FD) two-way relaying networks, where wireless power transfers from hybrid power access-point, H to user and wireless information transmits from user to H via relay. We propose FD-based power splitting (PS) and time-switching (TS) protocols which enables the energy harvesting (EH) and information processing at relay. These protocols overcome the limitation of spectral efficiency and in band self-interference caused by half-duplex relaying and operation of FD respectively. The energy constraint nodes such as relay and user harvest energy from H by radio-frequency signal, where relay also harvests energy by self-energy recycling. The optimal PS ratio and the optimal TS ratio are investigated and expressed in closed-form. With Rayleigh fading channel, we derive the end-to-end ergodic capacity for PS and TS protocols. Numerical results show that our proposed FD-based EH schemes outperform the benchmark schemes significantly. In particular, the PS protocol is superior to TS protocol at high transmit power of H while at low transmit power of H, TS protocol is better than the PS protocol.

Beamformer Design for Self-Energy Recycling in Full-Duplex Decode-and-Forward Relay Systems

We investigate the beamforming for the full-duplex self-energy recycling relay system with decode-and-forward protocol, where the relay received signal is divided into two circuits, one for the full-duplex relaying for the destination and the other for the energy harvesting through re-cycling of its RF energy. The beamforming vectors and the power splitting ratio at the relay are optimized to maximize the harvested energy while a certain reception quality threshold at the destination is met. Simulation results show how the performance of the proposed system is affected by various design factors such as numbers of relay antenna sets and analog interference cancellation level.

Energy Efficiency Evaluation for Downlink Full-Duplex Nonlinear MU-MIMO-OFDM System With Self-Energy Recycling

Energy-efficient wireless system design has gained considerable attraction owing to the widespread proliferation of wireless devices. The next-generation wireless systems should also be spectrally efficient to sustain the tremendous demand for wireless services. Full-duplex (FD) systems have the potential to double the spectral efficiency (SE) of current half-duplex communication systems. The major challenge in FD systems is the suppression of strong self-interference (SI) imposed by the transmit signal on its receiving antennas. However, SI can also be utilized for recycling of energy by exploiting the radio frequency energy harvesting (RFEH) techniques, which is commonly referred to as self-energy recycling (S-ER). S-ER improves the overall energy efficiency (EE) of the system via recycling a portion of transmitted power. In this article, we evaluate the EE for a downlink FD nonlinear multiuser multi-input-multi-output (MU-MIMO) orthogonal frequency division multiplexing (OFDM) system in the presence of S-ER. The proposed analytical formulation consists of closed-form derivation for EE and SE of the aforementioned system. Furthermore, we have also obtained the outage performance and based on this performance proposed a methodology to allocate the antennas for S-ER while satisfying the quality of service. It has been observed that reserving few antennas for S-ER improves the EE albeit with a slight degradation in SE due to reduced array gain. Consequently, with S-ER, the tradeoff between the SE and EE has been studied for a nonlinear MU-MIMO-OFDM system. Analytical derivation for EE, SE, and outage are followed by simulations for corroborating the proposed analysis.

Performance Analysis of a Full-Duplex MIMO Decode-and-Forward Relay System With Self-Energy Recycling

This paper analyzes the performance of the full-duplex (FD) multiple-input-multiple-output (MIMO) decode-and-forward (DF) relay system in the presence of self-energy recycling (S-ER). Specifically, this work proposes an antenna allocation scheme for S-ER as well as analytically evaluates the performance of this proposed scheme in terms of spectral efficiency (SE), energy efficiency (EE), outage and symbol error rate (SER). Since, the self-interference (SI) is a major bottleneck in achieving the true potentials of FD communication, this work considers SI as an energy harvesting opportunity to enhance the EE of the system. The proposed analysis shows that reserving few antennas for S-ER at the FD-MIMO relay improves the EE, however, it reduces the antenna array gain at the relay for information transmission and reception. Thus, a slight degradation in the SE, outage and SER is observed. Further, an adaptive S-ER technique has been proposed which utilizes the antennas corresponding to the least channel gain with respect to information transmission and reception for S-ER. This adaptive S-ER technique improves the EE and also compensates for the slight degradation in the SE, outage and SER through adaptive antenna allocation. Closed-form expressions for the SE, EE, outage and symbol error rate have been derived for these S-ER techniques. In the end, simulations results are provided to validate the efficacy of the theoretical derivations.

An Adaptive Self-Interference Cancelation/Utilization and ICA-Assisted Semi-Blind Full-Duplex Relay System for LLHR IoT

In this article, we propose a semi-blind full-duplex (FD) amplify-and-forward (AF) relay system with adaptive self-interference (SI) processing assisted by independent component analysis (ICA) for low-latency and high-reliability (LLHR) Internet of Things (IoT). The SI at FD relay is not necessarily canceled as much as possible like the conventional approaches, but is canceled or utilized based on a signal-to-residual-SI ratio (SRSIR) threshold at relay. According to the selected SI processing mode at relay, an ICA-based adaptive semi-blind scheme is proposed for signal separation and detection at destination. The proposed FD relay system not only features reduced signal processing cost of SI cancelation but also achieves a much higher degree of freedom in signal detection. The resulting bit error rate (BER) performance is robust against a wide range of SRSIR, much better than that of conventional FD systems, and close to the ideal case with perfect channel state information (CSI) and perfect SI cancelation. The proposed system also requires negligible spectral overhead as only a nonredundant precoding is needed for ambiguity elimination in ICA. In addition, the proposed system enables full resource utilization with consecutive data transmission at all time and same frequency, leading to much higher throughput and energy efficiency than the time-splitting and power-splitting-based self-energy recycling approaches that utilize only partial resources. Furthermore, an intensive analysis is provided, where the SRSIR thresholds for the adaptive SI processing mode selection and the BER expressions with ICA incurred ambiguities are derived.