In this paper, we analyze the security-reliability tradeoff (SRT) performance of the multi-relay cooperative networks over Nakagami-m fading channels. By considering the reliability of the first phase from the source to relay, a cooperative jamming (CJ) assisted secure transmission scheme is investigated to improve the security performance of the considered system. Specifically, we derive the approximate closed-form expression of the outage probability (OP) and exact closed-form expression of the intercepted probability (IP) for the CJ scheme to evaluate the SRT performance of the system. Finally, the simulation results verify the validity of our theoretical derivations and the advantage of the CJ scheme compared to the traditional scheme with no cooperative jammer.
In this paper, we analyze the security-reliability tradeoff (SRT) performance of the multi-relay cooperative networks over Nakagami-m fading channels. By considering the reliability of the first phase from the source to relay, a cooperative jamming (CJ) assisted secure transmission scheme is investigated to improve the security performance of the considered system. Specifically, we derive the approximate closed-form expression of the outage probability (OP) and exact closed-form expression of the intercepted probability (IP) for the CJ scheme to evaluate the SRT performance of the system. Finally, the simulation results verify the validity of our theoretical derivations and the advantage of the CJ scheme compared to the traditional scheme with no cooperative jammer.
In this paper, we investigate a novel joint multi-relay and jammer selection (JMRJS) scheme in order to improve the physical layer security of wireless networks. In the JMRJS scheme, all the relays succeeding in source decoding are selected to assist in the source signal transmission and meanwhile, all the remaining relay nodes are employed to act as friendly jammers to disturb the eavesdroppers by broadcasting artificial noise. Based on the more general Nakagami-m fading channel, we analyze the security performance of the JMRJS scheme for protecting the source signal against eavesdropping. The exact closed-form expressions of outage probability (OP) and intercept probability (IP) for the JMRJS scheme over Nakagami-m fading channel are derived. Moreover, we analyze the security-reliability tradeoff (SRT) of this scheme. Simulation results show that as the number of decode-and-forward (DF)relay nodes increases, the SRT of the JMRJS scheme improves notably. And when the transmit power is below a certain value, the SRT of the JMRJS scheme consistently outperforms the joint single-relay and jammer selection (JSRJS) scheme and joint equal-relay and jammer selection (JERJS) scheme respectively. In addition, the SRT of this scheme is always better than that of the multi-relay selection (MRS) scheme.
In this paper, we investigate a cooperative communication system comprised of a source, a destination, and multiple decode-and-forward (DF) relays in the presence of a potential malicious eavesdropper is within or without the coverage area of the source. Based on the more general Nakagami-m fading channels, we analyze the security performance of the single-relay selection and multi-relay selection schemes for protecting the source against eavesdropping. In the single-relay selection scheme, only the best relay is chosen to assist in the source transmission. Differing from the single-relay selection, multi-relay selection scheme allows multiple relays to forward the source to the destination. We also consider the classic direct transmission as a benchmark scheme to compare with the two relay selection schemes. We derive the exact closed-form expressions of outage probability (OP) and intercept probability (IP) for the direct transmission, the single-relay selection as well as the multi-relay selection scheme over Nakagami-m fading channel when the eavesdropper is within and without the coverage area of the source. Moreover, the security-reliability tradeoff (SRT) of these three schemes are also analyzed. It is verified that the SRT of the multi-relay selection consistently outperforms the single-relay selection, which of both the single-relay and multi-relay selection schemes outperform the direct transmission when the number of relays is large, no matter the eavesdropper is within or without the coverage of the source. In addition, as the number of DF relays increases, the SRT of relay selection schemes improve notably. However, the SRT of both two relay selection approaches become worse when the eavesdropper is within the coverage area of the source.
In this paper, we investigate the secrecy performance of the multi-antenna relaying networks over Rayleigh fading channels, by taking the reliability of the first link spanning the transmitter to the relays into consideration. To improve the secrecy performance, two secure transmission strategies are designed at relays, namely, 1) Maximal ratio combining/Transmitter antenna selection (MRC/TAS) and 2) MRC/Maximal ratio transmission (MRC/MRT), assisted by a friendly jammer. Specifically, in order to present the advantages of the two proposed schemes, we derive the exact closed-form expressions of the outage probability (OP) and intercept probability (IP) to evaluate the security-reliability tradeoff (SRT) of the considered system, respectively. From our theoretical analysis as well as simulation results, we find that a) our proposed schemes outperform the conventional scheme with no cooperative jammer (CJ), and b) the MRT scheme is superior to the TAS one conditioned on the same set of system parameters.
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.
In this paper, the secrecy performance of cooperative heterogeneous networks with unreliable backhaul over Nakagami- m fading channels is investigated. To secure the proposed system, a friendly jammer is considered to confuse eavesdroppers. To transmit the signals from the source to the destination, a two-phase transmitter/relay selection scheme is proposed. The best transmitter is selected when the signal-to-noise ratio at the relays is maximized. In the second phase, the best relay is chosen when the jamming signal-to-interference-plus-noise ratio of the eavesdroppers is minimized. To investigate the system performance, closed -form expressions are derived for the secrecy outage probability, ergodic capacity and non-zero achievable secrecy rate. In order to gain an insight into the system, asymptotic analysis is also provided. The results show that the degree of cooperative transmission and backhaul reliability are key parameters in the system and these parameters determine the secrecy performance.
In this paper, we explore a cooperative decode-and-forward (DF) relay network comprised of a source, a relay, and a destination in the presence of an eavesdropper. To improve physical-layer security of the relay system, we propose a jamming aided decode-and-forward relay (JDFR) scheme combining the use of artificial noise and DF relaying which requires two stages to transmit a packet. Specifically, in stage one, the source sends confidential message to the relay while the destination acts as a friendly jammer and transmits artificial noise to confound the eavesdropper. In stage two, the relay forwards its re-encoded message to the destination while the source emits artificial noise to confuse the eavesdropper. In addition, we analyze the security-reliability tradeoff (SRT) performance of the proposed JDFR scheme, where security and reliability are evaluated by deriving intercept probability (IP) and outage probability (OP), respectively. For the purpose of comparison, SRT of the traditional decode-and-forward relay (TDFR) scheme is also analyzed. Numerical results show that the SRT performance of the proposed JDFR scheme is better than that of the TDFR scheme. Also, it is shown that for the JDFR scheme, a better SRT performance can be obtained by the optimal power allocation (OPA) between the friendly jammer and user.