Secure Communications in CIoT Networks with a Wireless Energy Harvesting Untrusted Relay

Abstract

The Internet of Things (IoT) represents a bright prospect that a variety of common appliances can connect to one another, as well as with the rest of the Internet, to vastly improve our lives. Unique communication and security challenges have been brought out by the limited hardware, low-complexity, and severe energy constraints of IoT devices. In addition, a severe spectrum scarcity problem has also been stimulated by the use of a large number of IoT devices. In this paper, cognitive IoT (CIoT) is considered where an IoT network works as the secondary system using underlay spectrum sharing. A wireless energy harvesting (EH) node is used as a relay to improve the coverage of an IoT device. However, the relay could be a potential eavesdropper to intercept the IoT device’s messages. This paper considers the problem of secure communication between the IoT device (e.g., sensor) and a destination (e.g., controller) via the wireless EH untrusted relay. Since the destination can be equipped with adequate energy supply, secure schemes based on destination-aided jamming are proposed based on power splitting (PS) and time splitting (TS) policies, called intuitive secure schemes based on PS (Int-PS), precoded secure scheme based on PS (Pre-PS), intuitive secure scheme based on TS (Int-TS) and precoded secure scheme based on TS (Pre-TS), respectively. The secure performances of the proposed schemes are evaluated through the metric of probability of successfully secure transmission (PSST), which represents the probability that the interference constraint of the primary user is satisfied and the secrecy rate is positive. PSST is analyzed for the proposed secure schemes, and the closed form expressions of PSST for Pre-PS and Pre-TS are derived and validated through simulation results. Numerical results show that the precoded secure schemes have better PSST than the intuitive secure schemes under similar power consumption. When the secure schemes based on PS and TS polices have similar PSST, the average transmit power consumption of the secure scheme based on TS is lower. The influences of power splitting and time slitting ratios are also discussed through simulations.

Analysis of delay‐sensitive performance in cognitive wireless sensor networks

“…The impact of increasing distance (r) between BS and SN is displayed on the DASE in Figure 3. It is shown that DASE gradually decreases with r for Equation (13) and sharply decreases for Equation (11). Moreover, DASE increases as r increases upto a certain value and then decreases with r, so it has an optimal value of r which gives the maximum value of DASE is 9.936 × 10 −3 at r = 1.7.…”

“…Moreover, DASE increases as r increases upto a certain value and then decreases with r, so it has an optimal value of r which gives the maximum value of DASE is 9.936 × 10 −3 at r = 1.7. For the value of r = 0.7, the improvement of Equation (13) are 52.54% and 99.99% from Equations (11) and (15), respectively. Considering their improvement, it can be proclaimed that Equation (13) gives the highest value of DASE, so the RF pollution is low.…”

“…Figure 4 demonstrates the effect of transmission power (P s ) on DASE. In Equations (11) and (15), it is observed that the DASE increases as P s increases upto a certain value and then decreases. In Equation (11), DASE increases from P s = 11 dBm and the maximum value is 3.716 × 10 −2 at P s = 26 dBm.…”

Secrecy Outage Probability of a NOMA Scheme and Impact Imperfect Channel State Information in Underlay Cooperative Cognitive Networks

“…A considerable amount of literature has been published on PLS [14][15][16]. In [14], the authors analyzed the secrecy performance of cooperative protocols with relay selection methods influenced by co-channel interference.…”

Defending Against Randomly Located Eavesdroppers by Establishing a Protecting Region

“…Against this background, physical layer security (PLS) has been receiving great research attention [5]. Compared to traditional key-based cryptographic techniques applied to upper layers which can be deciphered, PLS which exploits the channel characters to enhance security, can safeguard wireless data transmissions without requiring secret keys and complex algorithms [6][7][8]. The main design goal of PLS is to increase the performance difference between the link of the legitimate receiver and that of the eavesdropper by using well-designed transmission schemes in the wireless sensor networks [9].…”