In this paper, we propose an energy harvestingbased jamming scheme to enhance secrecy outage probability (SOP) for cooperative relaying protocols. In the proposed scheme, one of available relays is selected to forward data from a source to a destination, while an energy-constrained relay harvests energy from the source's radio frequency signals to generate artificial noise to an eavesdropper. Moreover, we consider a generalized relay selection scheme, in which the Nth-best relay is resorted to help the source-destination communication. We derive exact and asymptotic expressions of the SOP over Rayleigh fading channels. Monte-Carlo simulations are performed to verify the analysis results and confirm the advantage of the proposed scheme.
In this paper, we propose an energy harvestingbased jamming scheme to enhance secrecy outage probability (SOP) for cooperative relaying protocols. In the proposed scheme, one of available relays is selected to forward data from a source to a destination, while an energy-constrained relay harvests energy from the source's radio frequency signals to generate artificial noise to an eavesdropper. Moreover, we consider a generalized relay selection scheme, in which the Nth-best relay is resorted to help the source-destination communication. We derive exact and asymptotic expressions of the SOP over Rayleigh fading channels. Monte-Carlo simulations are performed to verify the analysis results and confirm the advantage of the proposed scheme.
In this paper, we study radio frequency energy harvesting (EH) in a wireless sensor network in the presence of multiple eavesdroppers (EAVs). Specifically, the sensor source and multiple sensor relays harvest energy from multiple power transfer stations (PTSs), and then, the source uses this harvested energy to transmit information to the base station (BS) with the help of the relays. During the transmission of information, the BS typically faces a risk of losing information due to the EAVs. Thus, to enhance the secrecy of the considered system, one of the relays acts as a jammer, using harvested energy to generate interference with the EAVs. We propose a best-relay-and-best-jammer scheme for this purpose and compare this scheme with other previous schemes. The exact closed-form expression for the secrecy outage probability (SOP) is obtained and is validated through Monte Carlo simulations. A near-optimal EH time algorithm is also proposed. In addition, the effects on the SOP of key system parameters such as the EH efficiency coefficient, the EH time, the distance between the relay and BS, the number of PTSs, the number of relays, and the number of EAVs are investigated. The results indicate that the proposed scheme generally outperforms both the best-relay-and-random-jammer scheme and the random-relay-and-best-jammer scheme in terms of the secrecy capacity.
In this study, the authors propose a cooperative transmission scheme with energy‐harvesting (EH) relays under wiretapping of an eavesdropper. In this scheme, the relays harvest energy from radio‐frequency (RF) signals of a source through power‐splitting receivers, and process arrived signals by amplify‐and‐forward (EH‐AF protocol) and decode‐and‐forward (EH‐DF protocol) technologies. In the proposed protocols, a best relay is selected at the destination so that the end‐to‐end achievable secrecy rates are maximal. Exact and asymptotic secrecy outage probability expressions are used to evaluate the EH‐AF and EH‐DF protocols, respectively, and are confirmed by Monte Carlo simulations. The simulation results show that (i) the EH‐DF protocol outperforms the EH‐AF protocol, and both proposed protocols are improved when the number of cooperative relays and the distances of the relay–eavesdropper links increase and the relays move toward the destination, (ii) the secrecy performance of the EH‐AF and EH‐DF protocols is the best at optimal power‐splitting ratios, which are obtained by the golden section search method, (iii) the energy conversion efficiency and the noise at RF‐to‐baseband conversion units seriously affect the proposed protocols, and finally, (iv) the theoretical analysis results fit those of the Monte Carlo simulations.
In this paper, we consider a multi-node-assisted two-hop cooperative network, where an energy constrained source (S) aims to establish secure communications with a legitimate user in the presence of an eavesdropper. The cooperative nodes simultaneously assist the transmission from base station to legitimate user. Each cooperative node applies power splitting protocol to coordinate the received signal energy for information decoding and energy harvesting. The power splitting ratios at multi-node are formulated based on decode-and-forward (DF) relaying protocols. Depending on the available channel state information (CSI) at the source, we propose two different jamming schemes for secrecy performance enhancement. An optimal node is selected as a jammer to interfere the eavesdropper or a relay to forward the information to legitimate user. we evaluate the network performance based on secrecy outage probability (SOP). In addition, simple and accurate approximations are obtained at different transmission speed thresholds. Furthermore, numerical results reveal that there exist unique splitting ratios and harvesting efficiency that minimize the SOP.
In this paper, we investigate the achievable secrecy rate in a relay channel where the source and the destination wish to keep the information confidential from an untrusted relay (potential eavesdropper). The relay has no energy supply, and harvests its required energy for relaying from its received signals. For radio-frequency (RF) Energy Harvesting (EH) at the relay, we adopt power splitting (PS) approach. We study the problem of achieving positive secrecy rates between the transmitter and the receiver while making use of an untrusted relay. Energy limitation at the relay makes the problem more interesting. Because, the relay must choose either to eavesdrop the signal to be able to decode or to harvest energy (from the information signal) to be able to forward the message. Our scheme to guarantee the secrecy uses cooperative jamming by either the destination or an extra jammer node. We derive the achievable secrecy rates for the compress-and-forward (CF) and amplify-and-forward (AF) relays for two different scenarios. First, we assume the destination and the jammer are two separate nodes. Then, we consider destination-assisted jamming. In addition, we let the relay to use both the sources and the jammers transmitted signals to harvest energy. Our numerical results show that our proposed schemes guarantee a positive secrecy rate by properly locating the jammer and allocating enough jamming power. However, for a given power budget (i.e., fixed total transmission and jamming power) there is an optimum amount for the jamming power.
In this paper, we consider a two-hop wireless system consisting of one source, one destination, one eavesdropper and multiple amplify-and-forward relays. A time-division duplex scheme is proposed that aims at minimizing the secrecy rate outage by selecting an optimal relay from the set of candidate relays. In the first time slot, the source transmits the information bearing signal, meanwhile the destination jams the eavesdropper. In the second slot, the selected relay forwards the received signals in amplify-and-forward fashion. Out of two hops, the eavesdropper can tap only the signal transmitted by the relay in the second hop. We obtain a closed-form expression of the end-to-end secrecy outage for instantaneous and statistical channel-state information of the eavesdropper. The analytical results suggest that the proposed destination-based jamming outperforms the conventional relay selection scheme without jamming. Monte Carlo simulations are performed to verify the analytical results.
In this paper, we analyze the secrecy performance of a dual hop communication system with decode and forward relay (DFR) in the presence of an eavesdropper (EAV), which operates in full duplex mode. The secrecy capacity of the system is enhanced by using a Hybrid scheme of combination of time switching-based relaying (TSR) and power splitting-based relaying (PSR). A novel scheme of assisting the confidential information transmission by simultaneous transmission of jamming signal is presented. Both relay and EAV harvest energy from RF signals by using the Hybrid scheme. The performance of the scheme is evaluated in terms of secrecy outage probability (SOP) under several conditions of network parameters and SNRs of inter node channels. We also compare the results of PSR scheme alone in terms of SOP with Hybrid scheme under our proposed jamming model. MATLAB based simulation of our scheme demonstrates significant reduction of SOP.