Today, wireless networks become the most popular way to communicate. However, information can be easily eavesdropped or extracted by eavesdroppers due to the broadcast nature of wireless communication. Multi-hop relay communication systems provide for higher secrecy performance than direct transmission techniques. In this paper, the physical layer secrecy performance of multi-hop decode-and-forward (DF) relay network is investigated in the presence of multiple passive eavesdroppers over Nakagami-m fading channels. To do so, we find out the exact closed-form expressions of existence probability of secrecy capacity and secrecy outage probability by using statistical characteristics of signal-to-noise ratio (SNR). Importantly, these expressions are in more general forms compared to other results in the literature. The proposed results show a quite agreement between numerical analysis and equivalent Monte-Carlo simulations.
Today, wireless networks become the most popular way to communicate. However, information can be easily eavesdropped or extracted by eavesdroppers due to the broadcast nature of wireless communication. Multi-hop relay communication systems provide for higher secrecy performance than direct transmission techniques. In this paper, the physical layer secrecy performance of multi-hop decode-and-forward (DF) relay network is investigated in the presence of multiple passive eavesdroppers over Nakagami-m fading channels. To do so, we find out the exact closed-form expressions of existence probability of secrecy capacity and secrecy outage probability by using statistical characteristics of signal-to-noise ratio (SNR). Importantly, these expressions are in more general forms compared to other results in the literature. The proposed results show a quite agreement between numerical analysis and equivalent Monte-Carlo simulations.
Secrecy Analysis in DF Relay Over Generalized-K Fading Channels
In this paper, we analyze the secrecy performance of the decode-and-forward (DF) relay system in generalized-K fading channels. In a typical four-node communications model, a source (S) sends confidential information to a destination (D) via a relay (R) using DF strategy in two time slots, while an eavesdropper (E) wants to overhear the information from S to D over generalized-K fading channels. To be more realistic, we assume that E can receive the signals of two time slots, and there is no direct link between S and D because of heavy fading. Based on those assumptions, we derive closed-form expressions for the secrecy outage probability (SOP) and ergodic secrecy capacity (ESC) by using a tight approximate probability density function of the generalized-K model. Furthermore, asymptotic expressions for the SOP and ESC are also derived in the high signal-to-noise ratio region, not only because we can get some insights about SOP and ESC, but also because expressions for SOP and ESC can be simplified significantly. The single relay system is subsequently extended into a multi-relay system, where the asymptotic SOP analysis of three proposed relay selection strategies is investigated. Moreover, the security-reliability tradeoff analysis in the multi-relay system is also presented given that S adopts a constant code rate. Finally, the Monte-Carlo simulation is used to demonstrate the accuracy of the derived closed-form expressions.
In this paper, we investigate the secrecy performance of cellular multiuser two-way decode-and-forward (DF) relay networks with physical-layer security constraints, wherein a multiantenna base station (BS) communicates bidirectionally with several single-antenna mobile stations (MSs) via single-antenna DF relay in the presence of a single-antenna eavesdropper. We employ antenna selection (AS) transmission scheme at the BS with MS scheduling. Specifically, we derive the closed-form expression for the secrecy outage probability (SOP) of the considered system under independent and identically distributed (i.i.d.) Rayleigh fading channels. To gain more insights into the system secrecy diversity order, we analyze the asymptotic secrecy outage behavior in the high signal-to-noise ratio (SNR) regime. Our results reveal that the SOP saturates in the medium-to-high SNR regime, and reduces the secrecy diversity order to zero. Finally, the numerical and simulation corroborate our theoretical and analytical findings.
In this paper, a source communicates to the destination with the cooperation of a relay, in the presence of an eavesdropper. All the links undergo Rayleigh fading and perfect decoding at the relays is not considered. The secrecy outage probability expression is evaluated for a decode-and-forward (DF) dual-hop cooperative relay network, both with and without the presence of direct source to eavesdropper transmission link. The performance of the maximal ratio combining (MRC) and selection combining (SC) diversity at the eavesdropper is investigated. Asymptotic and diversity gain analysis for both the single relay and multi-relay system is obtained, when average SNRs of source-relay and relay-destination links are balanced or unbalanced. We have shown that the increase in target secrecy rate and eavesdropper channel quality significantly affects the outage performance of the system. We have investigated the outage probability of optimal relay selection scheme, when either full instantaneous channel state information (ICSI) or statistical channel state information (SCSI) of all the links is available and have shown that there is improvement in the secrecy performance with the increase in the number of relays.
In this paper, we investigate the performance of cooperative amplify-and-forward (AF) multi-relay networks with relay selection strategy over independent and identically distributed (i.i.d.) Nakagami-m fading channels. In this system we study multiuser cooperative relaying to have a secure transmission from source to destination, since transmitted information may be wiretapped by multiple eavesdroppers. The secrecy outage probability is derived in closed-form using signal-to-noise-ratio statistics, while a useful expression is presented for the asymptotically low outage regime. Our results explicitly demonstrate significant improvement of the secrecy outage probability in the multi-relay scenario.
In the last decade, multi-hop cooperation has evolved bringing several advantages including coverage improvement, more reliability of wireless links, and power consumption reduction. Still, its application has raised several challenges, such as the need for secure transmission at each hop, algorithms to perform relay selection and the accurate models to facilitate performance analysis. This paper addresses the problem of physical layer (PHY) security in a multi-hop wireless cooperative network, where communication at each hop is assisted by multiple relays forming a cluster, each cluster being surrounded by multiple eavesdroppers which together may tap transmissions from both the source and the relays. The main focus of the study is on analyzing the benefits of various relay selection schemes for protecting the source-destination transmission against the eavesdroppers, which can collude and combine information via diversity combining techniques. To be specific, four relay selection schemes, which differ in the way they employ available measures link quality, are considered to deliver the source information to the destination via a decode-and-forward (DF) strategy. To evaluate the security performance of the multi-hop cooperative link in the presence of colluding eavesdroppers, we derive novel closed-form analytical expressions for the secrecy outage probability (SOP) with consideration of special cases of practical interest.
In the last decade, multi-hop cooperation has evolved bringing several advantages including coverage improvement, more reliability of wireless links, and power consumption reduction. Still, its application has raised several challenges, such as the need for secure transmission at each hop, algorithms to perform relay selection and the accurate models to facilitate performance analysis. This paper addresses the problem of physical layer (PHY) security in a multi-hop wireless cooperative network, where communication at each hop is assisted by multiple relays forming a cluster, each cluster being surrounded by multiple eavesdroppers which together may tap transmissions from both the source and the relays. The main focus of the study is on analyzing the benefits of various relay selection schemes for protecting the source-destination transmission against the eavesdroppers, which can collude and combine information via diversity combining techniques. To be specific, four relay selection schemes, which differ in the way they employ available measures link quality, are considered to deliver the source information to the destination via a decode-and-forward (DF) strategy. To evaluate the security performance of the multi-hop cooperative link in the presence of colluding eavesdroppers, we derive novel closed-form analytical expressions for the secrecy outage probability (SOP) with consideration of special cases of practical interest.