In this paper, we proposed a generalized energy harvesting (GEH) protocol and utilized a non-linear energy harvesting (EH) model for AF Multi-Antenna Relaying Systems. In particular, the GEH protocol is a optimal EH protocol based on time switching relaying (TSR) and power splitting relaying (PSR) protocols. The whole communication process contains two phases. In phase I, the source transmits certain signal to the relay, meanwhile the destination transmits an artificial noise (AN) to interfere with the passive eavesdropper. The relay harvests energy from the two nodes. In phase II, the relay node processes the two different received signals, which are transmitted from the source and destination. Then the relay amplify-and-forward them by utilizing the harvested energy. To accurately reflect the non-linear nature of the practical EH circuit of GEH-based systems, we apply a special kind of quasi-concave function named logistic (sigmoidal) function to model the input-output characteristic. We also derive a new analytical formula for proposed generalized non-linear energy harvesting protocol on ergodic secrecy capacity. The effect of the number of relay antennas N, the source transmitted power Pthe destination transmitted power Pd on ergodic secrecy capacity are investigated. The simulation results show that as N, Ps, Pd increase, the ergodic secrecy capacity of GEH system increases accordingly. Moreover, the GEH protocol can provide higher non-linear ergodic secrecy capacity than time switching relaying (TSR) protocol and almost perform as better as power splitting relaying (PSR) protocol.
In this paper, we proposed a generalized energy harvesting (GEH) protocol and utilized a non-linear energy harvesting (EH) model for AF Multi-Antenna Relaying Systems. In particular, the GEH protocol is a optimal EH protocol based on time switching relaying (TSR) and power splitting relaying (PSR) protocols. The whole communication process contains two phases. In phase I, the source transmits certain signal to the relay, meanwhile the destination transmits an artificial noise (AN) to interfere with the passive eavesdropper. The relay harvests energy from the two nodes. In phase II, the relay node processes the two different received signals, which are transmitted from the source and destination. Then the relay amplify-and-forward them by utilizing the harvested energy. To accurately reflect the non-linear nature of the practical EH circuit of GEH-based systems, we apply a special kind of quasi-concave function named logistic (sigmoidal) function to model the input-output characteristic. We also derive a new analytical formula for proposed generalized non-linear energy harvesting protocol on ergodic secrecy capacity. The effect of the number of relay antennas N, the source transmitted power Pthe destination transmitted power Pd on ergodic secrecy capacity are investigated. The simulation results show that as N, Ps, Pd increase, the ergodic secrecy capacity of GEH system increases accordingly. Moreover, the GEH protocol can provide higher non-linear ergodic secrecy capacity than time switching relaying (TSR) protocol and almost perform as better as power splitting relaying (PSR) protocol.
In this study, the authors propose a generalisedswitching protocol (GSP) for increasing the flexibility of energy harvesting (EH) protocol and enhancing the security of amplify‐and‐forward (AF) multi‐antenna relaying system. The proposed GSP‐based relaying [generalised switching relaying (GSR)] system is established with target node assisted interference and EH technologies. In phase I, while the source transmits certain signal to the relay, the destination transmits an artificial noise to interfere the passive eavesdropper. In this phase, the relay harvests energy from the two nodes. In phase II, the relay node processes the two different received signals, which are from the source and destination, then AF them by utilising the harvested energy. The authors also derive a new analytical formula for the proposed protocol on ergodic secrecy capacity. The effect of the number of relay antennas N , the source transmitted power , the destination transmitted power and EH efficiency factors and on ergodic secrecy capacity are investigated. The simulation results show that as N , , , and increase, the ergodic secrecy capacity of GSR system increases accordingly. Moreover, the GSR protocol can provide higher ergodic secrecy capacity than both time switching relaying and powersplitting relaying protocols.
In this paper, we analyze the secrecy capacity of a half-duplex energy harvesting (EH)-based multi-antenna amplify-and-forward relay network in the presence of a passive eavesdropper. During the first phase, while the source is in the transmission mode, the legitimate destination transmits an auxiliary artificial noise (AN) signal which has two distinct purposes: 1) to transfer power to the relay and 2) to improve system security. Since the AN is known at the legitimate destination, it is easily cancelled at the intended destination, which is not the case at the eavesdropper. In this respect, we derive new exact analytical expressions for the ergodic secrecy capacity for various well-known EH relaying protocols, namely, time switching relaying (TSR), power splitting relaying (PSR), and ideal relaying receiver (IRR). Monte Carlo simulations are also provided throughout our investigations to validate the analysis. The impacts of some important system parameters, such as EH time, power splitting ratio, relay location, AN power, EH efficiency, and the number of relay antennas, on the system performance are investigated. The results reveal that the PSR protocol generally outperforms the TSR approach in terms of the secrecy capacity.
This paper analyzes the ergodic secrecy capacity of an energy-constrained multiple-antennas amplify-and-forward (AF) relaying system in the presence of a passive eavesdropper. In the first phase, the source broadcasts information signal, while the destination sends an artificial jamming signal. The jamming signal has two main purposes: 1) enhancing the system security; 2) increasing the energy harvesting (EH) at the relay node. In the second phase, the relay uses the harvested energy to amplify and forward the received signal to the destination. For this system model, explicit mathematical expressions for the ergodic secrecy capacity are derived for three different common EH-relaying protocols, namely, power splitting relaying (PSR), antenna selection and power splitting (ASPS) receiver, and ideal relaying receiver (IRR). Monte-Carlo simulations are included to validate the analysis and the effect of different parameters on the system security are investigated. The results show that, the ASPS receiver outperforms PSR in terms of secrecy capacity.
This paper investigates the secrecy performance of amplified-and-forward (AF) relay wiretap model by using energy harvesting (EH) and signal alignment technique. All nodes equipped with multi antennas play different roles in terms of source, destination, relay, eavesdropper and jamming node. The jamming node designs artificial noise based on signal alignment principle, and then transmits it to the eavesdropper with harvested energy. Due to different power limitations, we propose power allocation schemes called Local Power Constraints scheme (LPCS) and Global Power Constraints scheme (GPCS), which maximize the secrecy rate of the system and obtain better secrecy performance when compared with the non-EH scheme and the partial nodes power allocation EH scheme. Furthermore, we also analyze the effect of the energy harvesting on the secure degrees of freedom (SDOF) in the high signal-to-noise (SNR) region, and simulate the secrecy performance with convex optimization method by proving the convexity of the optimization problem. Results show that the proposed schemes outperform the compared schemes on the secrecy performance, and achieve more secrecy rate when the destination and the relay have more antennas.
In this paper, the secure information transmission of an energy harvesting (EH) cooperative network is considered, in which multiple eavesdroppers can overhear the forwarded relay signal. To prevent multiple eavesdroppers from decoding confidential signals, the destination transmits the jamming signal while the source transmits the confidential signal to the relay. Simultaneously, the relay can harvest more energy from source signals and destination jamming by the power splitting (PS) protocol, which is depicted as a non-linear EH process. Considering the imperfect self-interference cancellation (SIC) at the destination, secrecy rate maximization optimization is formulated to optimize the transmission power of source and destination. However, the formulated optimization is non-convex. To solve this problem, an iterative algorithm is proposed based on the difference of convex functions (DC) programming, which can transform non-convex optimization problems into successive approximate convex problems. Simulation results show that the proposed algorithm has a quick convergence rate, and the proposed scheme leads to a higher achievable secrecy rate.
Energy harvesting (EH) has attracted a lot of attention in cooperative communication networks studies for its capability of transferring energy from sources to relays. In this paper, we study the secrecy capacity of a cooperative compressed sensing amplify and forward (CCS-AF) wireless network in the presence of eavesdroppers based on an energy harvesting protocol. In this model, the source nodes send their information to the relays simultaneously, and then the relays perform EH from the received radio-frequency signals based on the power splitting-based relaying (PSR) protocol. The energy harvested by the relays will be used to amplify and forward the received information to the destination. The impacts of some key parameters, such as the power splitting ratio, energy conversion efficiency, relay location, and the number of relays, on the system secrecy capacity are analyzed through a group of experiments. Simulation results reveal that under certain conditions, the proposed EH relaying scheme can achieve higher secrecy capacity than traditional relaying strategies while consuming equal or even less power.