Secure Communication via a Wireless Energy Harvesting Untrusted Relay

Abstract

Abstract-The broadcast nature of the wireless medium allows unintended users to eavesdrop the confidential information transmission. In this regard, we investigate the problem of secure communication between a source and a destination via a wireless energy harvesting untrusted node which acts as a helper to relay the information; however, the source and destination nodes wish to keep the information confidential from the relay node. To realize the positive secrecy rate, we use destination-assisted jamming. Being an energy-starved node, the untrusted relay harvests energy from the received radio frequency signals, which include the source's information signal and the destination's jamming signal. Thus, we utilize the jamming signal efficiently by leveraging it as a useful energy source. At the relay, to enable energy harvesting and information processing, we adopt power splitting (PS) and time switching (TS) policies. To evaluate the secrecy performance of this proposed scenario, we derive analytical expressions for two important metrics, viz., the secrecy outage probability and the ergodic secrecy rate. The numerical analysis reveals the design insights into the effects of different system parameters like power splitting ratio, energy harvesting time, target secrecy rate, transmit signal-to-noise ratio (SNR), relay location, and energy conversion efficiency factor, on the secrecy performance. Specifically, the PS policy achieves better optimal secrecy outage probability and optimal ergodic secrecy rate than that of the TS policy at higher target secrecy rate and transmit SNR, respectively. Index Terms-Destination-assisted jamming, ergodic secrecy rate, secrecy outage probability, untrusted relay, wireless energy harvesting.

Security–reliability tradeoff analysis of untrusted energy harvesting relay networks

“…We assume that the jamming signal can readily be cancelled off since it is known to the destination. 12,16,17 Secure transmission performance…”

“…Different from Kalamkar and Banerjee, 17 we adopt the fixed-rate transmission scheme to meet the security and reliability requirements, where the security is quantified in terms of the SOP, the reliability is quantified in terms of the connection outage probability (COP). The main contributions of this article are summarized as follows:…”

PHY-Aided Secure Communication via Weighted Fractional Fourier Transform

“…By exploiting the coding techniques as well as physical properties of wireless channels, PHY layer security has a great potential to achieve "perfect secrecy" and is identified as a significant complement to traditional cryptographic techniques [8]. As introduced in [9,10], the weighted fractional Fourier transform (WFRFT) is performed as a new paradigm for PHY layer security enhancement.…”

Secure wireless powered relaying networks: Energy harvesting policies and performance analysis

“…In the presence of an external ER, the work in Chen et al 14 examined secure communication between the source and the destination via an EH relay with multiple antennas while the authors in Xing et al 15 studied the secrecy performance of source-destination communication via multiple EH relays. [17][18][19][20][21][22][23] In Huang et al, 17 the authors investigated the secrecy performance of the communication via a multiple antenna untrusted relay in terms of secrecy outage probability. In cases without ERs, the transmission from the source to the destination is still compromised when one may wish to keep the source-destination communication confidential from the relay despite the help of the relay to forward the information.…”