Energy Harvesting Relay Network Research Articles

Delay sensitive data transmission optimization for energy harvesting relay satellite networks

Relay satellite network has become a promising architecture to provide rapid-response data offloading services for delay-sensitive space data. However, stochastic resources and dynamic inter-satellite contacts bring plenty of difficulties under delay constraints, which affects the transmission efficiency directly. In this paper, we first systematically analyze the data transmission process with delay guarantees and formulate a long-term stochastic optimization problem without a priori statistical knowledge. To tackle this problem, we first transform it into several sub-problems using a queue-stability-related technology. Then, we propose a transmission optimization with delay guarantees algorithm to maximize the system utility by optimizing resource allocation and channel assignment. Furthermore, we provide performance analysis to prove that the proposed algorithm can achieve long-term stability and approach near-optimal system utility. Finally, extensive simulations demonstrate the effectiveness of the proposed algorithm for system utility maximization and delay control.

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.

Outage performance of NOMA with Alamouti/MRC in dual-hop energy harvesting relay networks

This paper presents outage performance of Alamouti coding/maximum ratio combining (Alamouti/MRC) scheme in dual-hop non-orthogonal multiple access network taking advantage of simultaneous wireless information and power transfer (SWIPT). In the considered system, a base station simultaneously serves multiple users via energy harvesting enabled amplify-and-forward relay by exploiting Alamouti coding, and the users employ MRC technique. Thereby, not only spatial diversity is exploited but also channel state information burden can be reduced in terms of transmit diversity, in addition to increasing energy efficiency by SWIPT. Exact outage probability for any user is obtained over Nakagami-m fading channels by considering the channel estimation error (CEE), together with asymptotic expression providing more valuable insights. Besides, the sum throughput and energy efficiency are also investigated to characterize the system performance. Finally, the analytical results are verified by the Monte Carlo simulations. Results show that a variety of trade-off cases arise for optimum performance.

Performance of TAS/MRC in NOMA energy harvesting relay networks

This paper investigates the outage probability (OP) performance for multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) based energy harvesting (EH) relaying network. The base station communicates multiple users with the assistance of EH-relay. The optimal transmit antenna selection/maximal ratio combining (TAS/MRC) and sub-optimal majority-based TAS (TAS-maj)/MRC are employed in the first and second hops, respectively. We first derive the signal-to-interference-and-noise ratio (SINR) expressions. Then, the derived SINR expressions are used to obtain expressions of OP for each user in closed form in Nakagami-m fading channels. We finally verify the exactness of the theoretical analysis with the numerical results through Monte Carlo simulations. The results show that the outage performance improves considerably with the increased number of transmit and/or receive antennas and the enhanced channel conditions. Furthermore, regardless of the antenna’s configurations, the optimal position of the EH-based relay has to be close to the base station, while the optimal power division ratios for users vary. Moreover, the proposed TAS/MRC scheme is superior to the previous schemes, such as max–max–max and max–min–max-based MRC.

Adaptive secure transmission for two‐way energy harvesting relay networks with two‐sided eavesdropping

AbstractIn this paper, for energy harvesting (EH) two‐way relay (TWR) networks with two‐sided eavesdroppers, the problem of secure information transmission is investigated. Based on this system model, a novel full‐duplex (FD) relaying jamming scheme is proposed to achieve simultaneously information reception, EH and jamming signal transmission at the cooperative relay. Particularly, the entire transmission phase and received signal at relay node are divided into two different time durations and three different parts by time allocation (TA) and power splitting (PS), respectively. For the aim of maximizing the sum secrecy rate, adaptive TA factor and PS factor are jointly optimized. We derive the non‐convex optimization function. To solve this highly non‐convex optimization problem, a heuristic approach based on particle swarm optimization (PSO) is proposed. Numerical results verify the superior sum secrecy rate of the proposed scheme. Besides, the impact of system parameters on the output performance is analyzed.

Performance analysis of antenna selection scheme in dual-hop NOMA HD and FD energy harvesting relay networks

In this paper, the outage probability (OP) performance of antenna selection schemes is investigated in downlink non-orthogonal multiple access based energy harvesting amplify-and-forward relay network. In this network, base station with multiple antennas simultaneously communicates with multiple-antenna users via the relay, which is equipped with single transmit and multiple receive antennas and operates in half-duplex (HD) or full-duplex (FD) mode. The joint transmit-receive antenna selection and receive antenna selection schemes are employed in the first and second hops, respectively. For the proposed system, the closed-form expressions for the exact OP are derived jointly for HD and FD modes over Nakagami-m fading. Then, the corresponding asymptotic OP expressions are obtained. Finally, accuracy of our analyses is verified by simulations.

Secrecy capacity in two-way energy harvesting relay networks with a friendly jammer

Secrecy capacity in two-way energy harvesting relay networks with a friendly jammer

Multi-User PD-NOMA with unreliable backhaul links in a multiple EH relay network over Nakagami-m fading channels

In this paper, we analyze the performance of cooperative power-domain non-orthogonal multiple access systems (PD-NOMA) for multiple users in a multiple energy-harvesting (EH) relay network with unreliable backhaul links over Nakagami-m fading channels. In the proposed system, multi-destination users are allocated various powers and communicate with the best transmitter (Tx) via the best relay. EH relay employs a power-splitting relaying (PSR) architecture and an amplify-and-forward (AF) protocol. To evaluate the performance of each user and the overall system, closed-form analytical expressions for the outage probability (OP) and throughput over Nakagami-m fading channels are derived. Moreover, Monte Carlo simulations are used to verify the accuracy of the analytical results. In addition, the effects of key parameters of the system, such as the shape factor of the Nakagami-m channel model, power allocation, EH efficiency, power splitting ratio, and the number of relay nodes, on both the outage probability and throughput for multiple NOMA users are analyzed. These results show that the proposed PD-NOMA system offers better user-fairness in comparison with the conventional orthogonal multiple-access (OMA) system.

Outage analysis for NOMA‐based energy harvesting relay network with imperfect CSI and transmit antenna selection

In this study, a relay assisted order energy harvesting-based non-orthogonal multiple access (NOMA) network is considered where the relay harvests energy from radio frequency signal of the source. A transmit antenna selection scheme is considered at the source under imperfect channel state information (CSI). The outage probability of order NOMA network is analysed and a closed-form expression of it is obtained. A comparative performance study is carried out with perfect and imperfect successive interference cancellation at the receiver. The impact of a number of antennas available at the source on outage performance and the effect of imperfect CSI on the outage performance are also presented in this work. The upper limit of the order of the NOMA network to be supported for a given threshold signal to interference plus noise ratio (SINR) is also estimated.

Secrecy rate maximisation for non‐linear energy harvesting relay networks with cooperative jamming and imperfect channel state information

The secrecy performance of a wireless-powered relaying system is investigated in the presence of imperfect channel state information. To improve the system secrecy performance, the destination splits a part of power to transmit the cooperative interference signal while the source transmits confidential information to the relay. The relay is assumed to be equipped with a non-linear energy harvester and to harvest energy from the source and destination for information processing. A joint power splitting and time allocation scheme is studied to maximise the system secrecy rate. The joint optimisation problem is dealt with by the interior-point method. For the sake of comparison, the equal time allocation scheme and the equal power splitting scheme are also investigated. The numerical results verify that the proposed scheme could achieve higher secrecy rate.

Secure transmission for energy harvesting relay networks with the destination self-protection mechanism

In this paper, we investigate the physical layer security (PLS) of an energy harvesting (EH) cooperative network with the destination self-protection mechanism. More specifically, we consider a cooperative transmission scenario in which a source communicates with a destination through a wireless-powered relay using power splitting (PS) protocol in the presence of an eavesdropper. To degrade the wiretap channel, the destination is operated in full-duplex (FD) to achieve simultaneous information reception and jamming transmission. Taking into account the residual self-interference (SI) at the destination, the non-convex secrecy rate maximization problem is formulated to jointly optimize the PS factor and power allocation of source and destination. Due to the non-convexity of the joint optimization, a low complexity iterative algorithm based on the alternative search method and difference of convex functions (DC) programming is proposed. The original problem is first decomposed into two sub-problems with the fixed transmission power or PS factor. Since the decomposed two sub-problems are still non-convex, we utilize the DC programming to obtain the local solutions of the two sub-problems. Then the global solutions can be obtained by the alternative search method. Simulation results present that the proposed scheme has fast convergence. Comparing with other conventional schemes, the proposed scheme has the best security performance.

Optimal Power Allocation for Full-Duplex Underwater Relay Networks With Energy Harvesting: A Reinforcement Learning Approach

In this letter, we study the optimal power allocation problem where the goal is to maximize the long-term end-to-end sum rate of an underwater full-duplex energy harvesting relay network. The problem is formulated as an online sequential decision-making problem where the relay adapts the transmit power in each time-slot based on past and current information of harvested energy, battery level, channel state information, and interference level. The optimal transmission policy is obtained through the reinforcement learning framework. Simulation results show that the optimal online power allocation policy achieves a higher sum rate than the computationally-efficient sub-optimal online greedy power allocation policy, especially under insufficient harvested energy.

Outage probability analysis of dual energy harvesting relay network over rayleigh fading channel using SC and MRC technique

<p><span>In this paper, the system model of dual-energy harvesting relay network over Rayleigh fading channel and the comparison between Selecting Combining (SC) and Maximal Ratio Combining (MRC) technique cases are proposed and investigated. The closed-form expression of the outage probability for the SC case and the integral-form expression of the outage probability for MRC case is derived. Moreover, the influence of the main parameters on the system performance is demonstrated entirely by the Monte Carlo simulation. From the results, we can see that all simulation and analytical results match well with each other.</span></p>

Outage probability analysis of DF PSR energy harvesting full-duplex relaying network with presence of the direct link using MRC technique

<p>In the last time, the system performance of the energy harvesting relay network has been considered in many studies. In this paper, we propose and investigate the outage probability (OP) of the Decode-and-Forward (DF) Energy Harvesting (EH) Full-Duplex (FD) Relaying network in Power Splitting Protocol (PS) using MRC Technique with the presence of the direct link. In the first stage, the integral form of the OP is derived in two cases with and without the presence of the direct link. After that, we analyze the influence of main system parameters on the OP and comparison between two cases with and without the presence of the direct link. Finally, the results show that all simulation and analytical results match well with each other based on the Monte Carlo verification simulation.</p>

Adaptive Cooperative Jamming for Secure Communication in Energy Harvesting Relay Networks

This letter studies the problem of secure communication for a dual-hop energy harvesting (EH) relay network in the presence of multiple eavesdroppers. An adaptive cooperative jamming (ACJ) scheme is proposed, which can adaptively adjust power allocation factor to maximize the secrecy rate in practical networks where there is no eavesdroppers' channel-state-information (CSI). To evaluate the performance of the proposed scheme, we analyze the ergodic secrecy capacity (ESC) of multi-antenna networks using the ACJ, and derive the closed-form expressions of the ESC for large antenna systems. Simulation results show that the proposed scheme outperforms the benchmark scheme.

Performance improvement of multiuser cognitive relay networks with full-duplex cooperative sensing and energy harvesting

Energy harvesting cognitive radio has been considered as a promising technology in the fifth generation (5G) of wireless networks to solve the lack of spectrum and energy. In this paper, a novel wireless energy harvesting relay network is proposed for a multiuser cognitive radio to obtain the maximum throughput and decrease the false alarm and misdetection probabilities. The secondary user (SU) can harvest energy from solar sources while utilizing the licensed spectrum of the primary user (PU). Cooperative spectrum sensing is applied to improve the performance of the secondary network and decrease collision and sensing time. In this paper, the SU can carry out the transmitting, harvesting, and sensing using a full-duplex technique at the same time. Furthermore, we analyze the spectrum sensing of the proposed multiuser network under a data fusion scheme to discover the frequency hole. We demonstrate that the optimization problem can convert into a convex problem and achieve the optimal regulated rate of energy harvesting based on the Lagrangian function. This new network provides improved throughput, precise spectrum sensing, and high energy harvesting compared to the existing works studied so far. Finally, we verify the efficiency of the proposed method via simulation results and show that the optimal regulated rate is determined based on the priority of given constraints.

Performance analysis for power-splitting energy harvesting based two-way full-duplex relaying network over nakagami-m fading channel

Energy harvesting relay network is considered as the promising solution for a wireless communication network in our time. In this research, we present and demonstrate the system performance of the energy harvesting based two-way full-duplex relaying network over Nakagami-m fading environment. Firstly, we propose the analytical expressions of the achievable throughput and outage probability of the proposed system. In the second step, the effect of various system parameters on the system performance is presented and investigated. In the final step, the analytical results are also demonstrated by Monte-Carlo simulation. The numerical results demonstrated and convinced the analytical and the simulation results are agreed with each other.

Half-Duplex Energy Harvesting Relay Network over Different Fading Environment: System Performance with Effect of Hardware Impairment

In this paper, we introduce a half-duplex (HD) energy harvesting (EH) relay network over the different fading environment with the effect of hardware impairment (HI). The model system was investigated with the amplify-and-forward (AF) and the power splitting (PS) protocols. The system performance analysis in term of the outage probability (OP), achievable throughput (AT), and bit error rate (BER) were demonstrated with the closed-form expressions. In addition, the power splitting (PS) factor was investigated. We verified the analytical analysis by Monte Carlo simulation with all primary parameters. From the results, we can state that the analytical and simulation results match well with each other.

Exact Outage Analysis of Cognitive Energy Harvesting Relaying Networks under Physical Layer Security

In this paper, we study the secure communication of cognitive energy harvesting relay networks when there exist multiple eaves droppers who can overhear the message of the second hop, and multiple primary users are present. The data transmission from the secondary source to the secondary destination