Internet of Things (IoT), which can provide ubiquitous intelligence and pervasive interconnections to a variety of devices, is becoming a vital component of building the intelligent world. In this work we propose a new relay and jammer selection method to improve physical layer security (PLS) and energy efficiency for the IoT network with energy harvesting (EH) devices. In this method, the intermediate nodes are allowed to use time switching (TS) protocol to harvest energy from power transfer stations (PTS). By taking the channel gain between the PTSs and the intermediate nodes into consideration, two intermediate nodes are selected as relay and jammer respectively to transmit confidential and jamming signals to the destination and eavesdropper aiming at minimizing the secrecy outage probability (SOP). We further analyze the secrecy outage of the system and derive the closed-form expression of SOP. Simulation results demonstrate the performance gain of the proposed method.
Internet of Things (IoT), which can provide ubiquitous intelligence and pervasive interconnections to a variety of devices, is becoming a vital component of building the intelligent world. In this work we propose a new relay and jammer selection method to improve physical layer security (PLS) and energy efficiency for the IoT network with energy harvesting (EH) devices. In this method, the intermediate nodes are allowed to use time switching (TS) protocol to harvest energy from power transfer stations (PTS). By taking the channel gain between the PTSs and the intermediate nodes into consideration, two intermediate nodes are selected as relay and jammer respectively to transmit confidential and jamming signals to the destination and eavesdropper aiming at minimizing the secrecy outage probability (SOP). We further analyze the secrecy outage of the system and derive the closed-form expression of SOP. Simulation results demonstrate the performance gain of the proposed method.
In this paper, we investigate the security of relay wiretap networks for internet of things (IoT), in which a transmitter sends the information to the receiver with the help of the energy limited relays. Specifically, the optimal relay selection based on two energy harvesting (EH) schemes, i.e., power splitting relay protocol (PSR) and time switching relay protocol (TSR), are introduced to improve the secrecy performance of the considered system. On this basis, the exact closed-form secrecy outage probability (SOP) expressions of the system with two EH protocols are derived, respectively. Further, for more deep insights, the asymptotic SOP expressions are also achieved with infinity number of relays. From the results, we can conclude that the PSR protocol is better than TSR in terms of improving the secrecy performance of relay wiretap networks.
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.
Secure relay and jammer selection for physical-layer security is studied in a wireless network with multiple intermediate nodes and eavesdroppers, where each intermediate node either helps to forward messages as a relay, or broadcasts noise as a jammer. We derive a closed-form expression for the secrecy outage probability (SOP), and we develop two relay and jammer selection methods for SOP minimization. In both methods a selection vector and a corresponding threshold are designed and broadcast by the destination to ensure each intermediate node knows its own role while knowledge of the relay and jammer set is kept secret from all eavesdroppers. Simulation results show the SOP of the proposed methods are very close to that obtained by an exhaustive search, and that maintaining the privacy of the selection result greatly improves the SOP performance.
In this paper, the radio frequency energy harvesting (EH) and security issues in Internet of Things (IoT) sensor networks with multiple untrusted relays are considered. In particular, the communication protocol is divided into two phases. The first phase is used for EH, in which the IoT sensor nodes (SNs) and relays harvest energy from multiple power transfer stations. The second phase is used for information transmission in two steps: 1) the selected SN uses the harvested energy to broadcast information to the controller and the relays, and 2) the selected relay forwards information to the controller by applying the amplify-and-forward protocol to improve the quality of the communication between the SN and the controller. During information transmission, the controller is at risk of losing information because the relay may act as an eavesdropper (namely, an untrusted relay). Thus, to improve the secrecy performance of the considered system, we propose an optimal scheme, namely, best-sensor-best-untrusted-relay (BSBR) and compare this scheme with random-sensor-random-untrusted-relay and a threshold-based scheme. The closed-form expressions for the secrecy outage probability (SOP) and secrecy throughput (ST) are obtained and verified through Monte Carlo simulations to confirm the superior performance of our approach. EH time optimization and the target secrecy rate optimization algorithms are also proposed. In addition, the impacts of the EH time, the EH efficiency coefficient, the numbers of SNs and untrusted relays, and the target secrecy rate on the SOP and the ST are investigated. The results indicate that the BSBR generally outperforms the two baseline schemes in terms of the SOP and ST.
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.
Radio-frequency (RF) energy harvesting (EH) in wireless relaying networks has attracted considerable recent interest, especially for supplying energy to relay nodes in the Internet of Things (IoT) systems to assist the information exchange between a source and a destination. Moreover, limited hardware, computational resources, and energy availability of IoT devices have raised various security challenges. To this end, physical-layer security (PLS) has been proposed as an effective alternative to cryptographic methods for providing information security. In this study, we propose a PLS approach for simultaneous wireless information and power transfer (SWIPT)-based half-duplex (HD) amplify-and-forward (AF) relaying systems in the presence of an eavesdropper. Furthermore, we take into account both static power splitting relaying (SPSR) and dynamic power splitting relaying (DPSR) to thoroughly investigate the benefits of each one. To further enhance secure communication, we consider multiple friendly jammers to help prevent wiretapping attacks from the eavesdropper. More specifically, we provide a reliability and security analysis by deriving closed-form expressions of outage probability (OP) and intercept probability (IP), respectively, for both the SPSR and DPSR schemes. Then, simulations are also performed to validate our analysis and the effectiveness of the proposed schemes. Specifically, numerical results illustrate the nontrivial tradeoff between reliability and security of the proposed system. In addition, we conclude from the simulation results that the proposed DPSR scheme outperforms the SPSR-based scheme in terms of OP and IP under the influences of different parameters on system performance.