This paper investigates secure transmission in a wireless powered cooperative communication network (WPCCN) over Nakagami-$m$fading channels, where multiple intermediate energy harvesting (EH) nodes with finite energy storage are deployed to assist the secure transmission between source and destination in the presence of an eavesdropper. Specifically, the intermediate EH nodes first harvest and accumulate energy from the source's signal and then forward the confidential signal or emit jamming signal to interfere the eavesdropper according to actual requirements. In order to exploit the intermediate EH nodes for secure improvement, considering both energy storage status and channel gains, three relay-and-jammer selection schemes at the intermediate nodes are proposed, namely: energy threshold based best-relay and random-jammer (ETBR), energy threshold based random-relay and best-jammer (ETRB), and energy threshold based best-relay and best-jammer (ETBB). For understanding the impact of critical parameters on the secrecy performance, we first capture the evolution of the EH nodes’ storages using finite-state Markov chain (FSMC) and then derive the analytical expressions for hybrid outage probability (HOP) and secrecy throughput (ST). Furthermore, numerical results demonstrate that our proposed selection schemes outperform the existing schemes (bR-rJ, rR-bJ, bR-bJ) due to the consideration of energy accumulation and storage status. In addition, there is a suitable value of the energy threshold for each proposed scheme to achieve the optimal secrecy performance.
This paper investigates secure transmission in a wireless powered cooperative communication network (WPCCN) over Nakagami-mfading channels, where multiple intermediate energy harvesting (EH) nodes with finite energy storage are deployed to assist the secure transmission between source and destination in the presence of an eavesdropper. Specifically, the intermediate EH nodes first harvest and accumulate energy from the source's signal and then forward the confidential signal or emit jamming signal to interfere the eavesdropper according to actual requirements. In order to exploit the intermediate EH nodes for secure improvement, considering both energy storage status and channel gains, three relay-and-jammer selection schemes at the intermediate nodes are proposed, namely: energy threshold based best-relay and random-jammer (ETBR), energy threshold based random-relay and best-jammer (ETRB), and energy threshold based best-relay and best-jammer (ETBB). For understanding the impact of critical parameters on the secrecy performance, we first capture the evolution of the EH nodes’ storages using finite-state Markov chain (FSMC) and then derive the analytical expressions for hybrid outage probability (HOP) and secrecy throughput (ST). Furthermore, numerical results demonstrate that our proposed selection schemes outperform the existing schemes (bR-rJ, rR-bJ, bR-bJ) due to the consideration of energy accumulation and storage status. In addition, there is a suitable value of the energy threshold for each proposed scheme to achieve the optimal secrecy performance.
This paper investigates secure transmission in a wireless powered communication network (WPCN) with an energy harvesting (EH) source configured with multiple antennas. In the WPCN, the EH source harvests energy from the radio frequency (RF) signals broadcasted by a power beacon (PB), and purely relies on the harvested energy to communicate with the destination in the presence of passive eavesdroppers. It is noteworthy that the RF-EH source is equipped with a finite energy storage to accumulate the harvested energy. To enhance the security, we propose an energy-aware transmit antenna selection (EATAS) scheme. According to the energy status and the channel quality, the source adaptively decides to transmit confidential information or harvest RF energy. For evaluating the secrecy performance, we first study the evolution of the energy storage, and then derive the analytical expressions of connection outage probability (COP), secrecy outage probability (SOP) and effective secrecy throughput (EST). Numerical results demonstrate that our proposed scheme outperforms the existing accumulate-then-transmit (ATT) scheme.
This paper investigates secure transmission in a wireless powered communication network (WPCN) with an energy harvesting (EH) source configured with multiple antennas. In the WPCN, the EH source harvests energy from the radio frequency (RF) signals broadcasted by a power beacon (PB), and purely relies on the harvested energy to communicate with the destination in the presence of passive eavesdroppers. It is noteworthy that the RF-EH source is equipped with a finite energy storage to accumulate the harvested energy for the future usage. Moreover, due to energy-constraint and complexity- limitation, the multi-antenna source is only configured with a single RF-chain. To enhance the security for the WPCN, we propose two adaptive transmission schemes, i.e., energy-aware transmit antenna selection (EATAS) and energy-aware differential spatial modulation (EADSM). According to the energy status and the channel quality, the source adaptively decides whether to transmit confidential information or harvest RF energy. To evaluate the secrecy performance of the proposed schemes, we first study the evolution of the energy storage, and then derive the analytical expressions of connection outage probability (COP), secrecy outage probability (SOP) and efficient secrecy throughput (EST). Numerical results demonstrate that our proposed schemes outperform the existing schemes, i.e., time-switching based TAS (TS-TAS) and accumulate-then-transmit (ATT). And, increasing the transmit power of the PB or the capacity of the source's energy storage is helpful to improve the secrecy performance. Moreover, there exists an optimal transmission rate for each proposed scheme to achieve best secrecy performance.
Energy harvesting (EH) technology has imposed new constraints on the amount of time an energy-constrained relay node needs to use for EH and information forwarding. Moreover, EH techniques may increase vulnerability to eavesdropping, since a power receiver, as a potential eavesdropper, usually has a shorter access distance than an information receiver. Motivated by this issue, in this paper, we investigate a tradeoff between energy consumption and physical layer security in a wireless powered-untrusted cooperative communication (WPUCC) network consisting of one source-destination pair and multiple amplify-and-forward untrusted relays. To minimize the energy consumption of the network, we propose a secure adaptive relay-based cooperation approach. Moreover, a greedy battery-aware relay-selection scheme is proposed to minimize the power consumption in WPUCC systems. Using power-splitting-based energy accumulation, untrusted relays attempt to intercept the information intended to the legitimate destination while harvesting energy at the same time. To keep the information secure from potential eavesdropping, the source injects a jamming signal along with its data signal. By modeling the dynamic behavior of the relay battery as a finite-state Markov chain, we derive an analytical expression for the secrecy outage probability of our proposed secure adaptive harvest-use-store cooperative communication scheme and show that it is more secure than its direct transmission and pure two-hop transmission counterparts.
In this letter, we consider a cooperative wireless network consisting of a source, multiple intermediate energy harvesting nodes, and a destination, in the presence of a passive eavesdropper. First, the intermediate nodes use the time switching-based relaying protocol to harvest energy from the source signal. Then, a pair out of intermediate nodes are selected as a relay and a jammer to transmit confidential and jamming signals to the destination and eavesdropper. Under these assumptions, we evaluate the system performance in terms of secrecy outage probability.
In this paper, we investigate secure communication in a hybrid relay (HR)-assisted wireless powered cooperative communication network (WPCCN), where an eavesdropper tries to intercept the data transmitted by a source user and the HR simultaneously. The HR has the ability to wireless powered the energy-constrained multiple users in the downlink and to relay the received confidential information in the uplink. In particular, the full-duplex destination-based jamming (FD-DBJ) strategy is exploited to improve the secrecy performance. Moreover, in order to conduct effective secure communications, we design two multiuser scheduling schemes, i.e., random user selection (RUS), and best user selection (BUS) based on the main channel quality. In order to evaluate the secrecy performance, we analytically derive the energy outage probability (EOP), the secrecy outage probability (SOP), and the hybrid outage probability (HOP), respectively. As such, we formulate the secrecy throughput (ST) maximization problem to optimize the predetermined transmission rate. Our analysis and numerical results reveal that: 1) The BUS scheme has better security performance. 2) Both of the energy conversion efficiency and the number of users have a positive effect on secrecy performance. 3) The FD-DBJ scheme is an effective method to achieve secure communications. 4) The time-switching factor and predetermined transmission rate have a crucial influence on the secrecy performance, which should be considered carefully in system design.
In this paper, we investigate the physical layer security (PLS) of a wireless sensor network (WSN) that consists of a base station (BS), multiple sensor nodes (SNs), and multiple energy-limited relays (ERs) in the presence of a passive eavesdropper (EAV). We adopt a time-switching/power-splitting (TSPS) mechanism for information transmission. The communication protocol is divided into two phases. The purpose of the first phase is to decode information, and energy harvesting (EH) is performed in accordance with the TSPS protocol. The purpose of the second phase is to transmit information to multiple destinations using the amplify-and-forward (AF) technique. In this study, we introduce a multirelay cooperative scheme (MRCS) to improve the secrecy performance. We derive analytical expressions for the secrecy outage probability (SOP) of the MRCS and that of the noncooperative relay scheme (NCRS) by using the statistical characteristics of the signal-to-noise ratio (SNR). Specifically, we propose an optimal relay selection scheme to guarantee the security of the system for the MRCS. In addition, Monte Carlo simulation results are presented to confirm the accuracy of our analysis based on simulations of the secrecy performance under various system parameters, such as the positions and number of ERs, the EH time, and the EH efficiency coefficients. Finally, the simulation results show that the secrecy performance of our MRCS is higher than that of the NCRS and the traditional cooperative relay scheme (TCRS).