This paper investigates the physical-layer security (PLS) of wireless transmissions with the aid of multiple decode-and-forward one-way relays in the presence of both eavesdropping attacks and channel estimation errors (CEEs). To protect wireless transmission with CEE, two opportunistic relaying schemes are conceived to upgrade the PLS of the wireless communications with the aid of relays, namely, the CEE-oriented pure relay selection (CEE-PRS) and CEE-oriented jammer-aided relay selection (CEE-JRS), respectively. Moreover, the security-reliability tradeoff (SRT) is designed due to that increasing the transmit power may enhance the reliability, but the security may be sacrificed concurrently, where the security and reliability are characterized by the intercept probability (IP) and outage probability (OP), respectively. We then analyze the IP and OP of the CEE-PRS and CEE-JRS schemes. Furthermore, both the CEE-oriented direct transmission (CEE-DT) and the perfect channel estimation-oriented direct transmission (PCE-DT) schemes are also analyzed for comparison purposes. It is shown that although the SRT of the wireless communications can indeed be degraded by the eavesdropping attacks in low CEE regions, the proposed CEE-PRS and CEE-JRS schemes are capable of significant improving the SRT performance of wireless communications, demonstrating the advantage of the proposed CEE-PRS and CEE-JRS schemes against eavesdropping.
This paper investigates the physical-layer security (PLS) of wireless transmissions with the aid of multiple decode-and-forward one-way relays in the presence of both eavesdropping attacks and channel estimation errors (CEEs). To protect wireless transmission with CEE, two opportunistic relaying schemes are conceived to upgrade the PLS of the wireless communications with the aid of relays, namely, the CEE-oriented pure relay selection (CEE-PRS) and CEE-oriented jammer-aided relay selection (CEE-JRS), respectively. Moreover, the security-reliability tradeoff (SRT) is designed due to that increasing the transmit power may enhance the reliability, but the security may be sacrificed concurrently, where the security and reliability are characterized by the intercept probability (IP) and outage probability (OP), respectively. We then analyze the IP and OP of the CEE-PRS and CEE-JRS schemes. Furthermore, both the CEE-oriented direct transmission (CEE-DT) and the perfect channel estimation-oriented direct transmission (PCE-DT) schemes are also analyzed for comparison purposes. It is shown that although the SRT of the wireless communications can indeed be degraded by the eavesdropping attacks in low CEE regions, the proposed CEE-PRS and CEE-JRS schemes are capable of significant improving the SRT performance of wireless communications, demonstrating the advantage of the proposed CEE-PRS and CEE-JRS schemes against eavesdropping.
In this paper, we explore the physical layer security of an Internet of Things (IoT) network comprised of multiple relay-user pairs in the presence of multiple malicious eavesdroppers and channel estimation error (CEE). In order to guarantee secure transmission with channel estimation error, we propose a channel estimation error oriented joint relay-user pair and friendly jammer selection (CEE-JRUPaFJS) scheme to improve the physical layer security of IoT networks. For the purpose of comparison, the channel estimation error oriented traditional round-robin (CEE-TRR) scheme and the channel estimation error oriented traditional pure relay-user pair selection (CEE-TPRUPS) scheme are considered as benchmark schemes. The exact closed-form expressions of outage probability (OP) and intercept probability (IP) for the CEE-TRR and CEE-TPRUPS schemes as well as the CEE-JRUPaFJS scheme are derived over Rayleigh fading channels, which are employed to characterize network reliability and security, respectively. Moreover, the security-reliability tradeoff (SRT) is analyzed as a metric to evaluate the tradeoff performance of CEE-JRUPaFJS scheme. It is verified that the proposed CEE-JRUPaFJS scheme is superior to both the CEE-TRR and CEE-TPRUPS schemes in terms of SRT, which demonstrates our proposed CEE-JRUPaFJS scheme are capable of improving the security and reliability performance of IoT networks in the face of multiple eavesdroppers. Moreover, as the number of relay-user pairs increases, CEE-TPRUPS and CEE-JRUPaFJS schemes offer significant increases in SRT. Conversely, with an increasing number of eavesdroppers, the SRT of all these three schemes become worse.
In this paper, we investigate the physical-layer security for a wireless two-hop relay network in the presence of channel estimation errors when estimating the channel state information (CSI) of the main links (from the source via relays to the destination) and wiretap links (from the source and relays to the eavesdropper). The eavesdropper can not only overhear the confidential signals transmitted by the relays, but also tap the secret messages transmitted by the source. We present an channel estimation error oriented relay selection (CEEoRS) scheme to improve the security-reliability tradeoff (SRT). We also analyze the intercept probability and outage probability of the CEEoRS scheme, where the intercept probability and outage probability can quantify the security and reliability, respectively. For comparison purposes, the traditional direct transmission with channel estimation errors (TDTwCEE) is also analyzed. It is shown that the proposed CEEoRS scheme outperforms the TDTwCEE scheme in terms of its SRT. More specifically, the proposed CEEoRS scheme is capable of significantly improving the SRT performance of wireless communications through increasing the number of relays.
In this paper, we investigate the physical-layer security of cooperative communications relying on multiple two-way relays using the decode-and-forward (DF) protocol in the presence of an eavesdropper, where the eavesdropper appears to tap the transmissions of both the source and of the relay. The design tradeoff to be resolved is that the throughput is improved by invoking two-way relaying, but the secrecy of wireless transmissions may be degraded, since the eavesdropper may overhear the signals transmitted by both the source and relay nodes. We conceive an artificial noise aided two-way opportunistic relay selection (ANaTWORS) scheme for enhancing the security of the pair of source nodes communicating with the assistance of multiple two-way relays. Furthermore, we analyze both the outage probability and intercept probability of the proposed ANaTWORS scheme, where the security and reliability are characterized in terms of the intercept probability and the security outage probability. For comparison, we also provide the security-reliability tradeoff (SRT) analysis of both the traditional direct transmission and of the one-way relaying schemes. It is shown that the proposed ANaTWORS scheme outperforms both the conventional direct transmission, as well as the one-way relay methods in terms of its SRT. More specifically, in the low main-user-to-eavesdropper ratio (MUER) region, the proposed ANaTWORS scheme is capable of guaranteeing secure transmissions, whereas no SRT gain is achieved by conventional one-way relaying. In fact, the one-way relaying scheme may even be inferior to the traditional direct transmission scheme in terms of its SRT.
Joint Relay and Eavesdropper Selection Strategy Against Multiple Eavesdroppers over Nakagami-m Fading Channels in Cooperative Decode-and-Forward Relay Networks
Physical layer security (PLS) in the presence of multiple eavesdroppers over Nakagami-m fading channels for cooperative decode-and-forward (DF) relay network that consists of one source, one destination, and multiple relays is investigated. Different from the recent PLS system model that only considers one eavesdropper during eavesdropping attack, this paper extends the one-eavesdropper case to a multiple-eavesdropper scenario and investigates joint relay and eavesdropper selection (JRES) strategy against eavesdropping attack over Nakagami-m fading channels. In the proposed strategy, the best relay is selected via the maximum relay forward channel capacity. In addition, since eavesdroppers are noncooperative, the worst case is considered. Namely, the wiretap channel between the best relay and the chosen eavesdropper has the maximum capacity. Traditional direct transmission and opportunistic relay selection (ORS) scheme in the presence of one eavesdropper over Rayleigh channel are regarded as benchmarks. Moreover, a security-reliability tradeoff (SRT) performance is analyzed, where the reliability performance is expressed by outage probability (OP), while the security performance is measured by intercept probability (IP). Closed-form expressions of OP and IP are derived. The numerical results show that the proposed JRES scheme outperforms the traditional direct transmission and the ORS scheme in the presence of one eavesdropper over Rayleigh channel. The SRT performance is enhanced obviously with the increasing of relay numbers and Nakagami channel fading factor m for a given number of eavesdroppers, which extends the PLS and SRT performance analysis to a more general case in a cooperative DF relay network.
With the large-scale commercialization of 5G networks, the era of Internet of Things (IoT), which is oriented toward the Internet of Everything (IoE), is coming. Under the circumstance, reliable and secure communication are the great challenges for future wireless network because of the broadcasting characteristics of electromagnetic wave. Physical-layer security (PLS) is an effective way to ensure secure communication by exploiting random nature of fading channels. Motivated by this, we investigate PLS of the wireless-powered cooperative multirelaying for IoT networks in the presence of eavesdropper with the estimation errors of channel (EEC) and imbalance between in-phase and quadrature-phase (IIQ). Specifically, the relays can be charged by the source with the aid of energy harvesters, and a novel more secure modify-and-forward (MF) relay protocol is proposed. For further improving energy efficiency and reducing extra interference, theKth superior relay selection scheme is proposed since some best ones are not available due to some scheduling or failure. Based on the system under study, we derive the analytical expressions for the outage probability (OP), intercept probability (IP), and secrecy OP (SOP) to evaluate the reliable and secure performance of this consideration system. Particularly, we then analyze the asymptotic behaviors of the OP, IP, and SOP, respectively. Through computer simulation, we show that: 1) with EEC, the error floors of the OP and SOP are of presence; 2) multiple relays lead to better OP and SOP performance; and 3) IIQ improves the security and is detrimental to the system reliability.
This article examines secrecy coding aided wireless communications from a source to a destination in the presence of an eavesdropper from an SRT perspective. Explicitly, security is quantified in terms of the intercept probability experienced at the eavesdropper, while the outage probability encountered at the destination is used to measure transmission reliability. We characterize the SRT of conventional direct transmission from the source to the destination and show that if the outage probability is increased, the intercept probability decreases, and vice versa. We first demonstrate that the employment of relay nodes for assisting source-destination transmission is capable of defending against eavesdropping, followed by quantifying the benefits of SRS as well as MRS schemes. More specifically, in the SRS scheme, only the single "best" relay is selected for forwarding the source signal to the destination, whereas the MRS scheme allows multiple relays to participate in this process. It is illustrated that both the SRS and MRS schemes achieve a better SRT than conventional direct transmission, especially upon increasing the number of relays. Numerical results also show that, as expected, MRS outperforms SRS in terms of its SRT. Additionally, we present some open challenges and future directions for wireless relay aided physical-layer security.