In this paper, we propose a secure transmission scheme from a source to a destination in the presence of spatially random eavesdroppers, the distribution of which is modeled as a homogeneous Possion point process (PPP). In addition to transmitting the message signal, the source is allowed to use part of its power to transmit jamming signals in order to interfere the eavesdroppers. We assume the destination has the knowledge of the jamming signals. Based on the stochastic geometry and point process theory, we derive the closed-form expressions for the connection outage probability and the secrecy outage probability to characterize the reliability and the security performance, respectively. And we determine the optimal power allocation factor and wiretap code rates which maximize the secrecy throughput of the wiretap channel under secrecy outage probability constraint.
In this paper, we propose a secure transmission scheme from a source to a destination in the presence of spatially random eavesdroppers, the distribution of which is modeled as a homogeneous Possion point process (PPP). In addition to transmitting the message signal, the source is allowed to use part of its power to transmit jamming signals in order to interfere the eavesdroppers. We assume the destination has the knowledge of the jamming signals. Based on the stochastic geometry and point process theory, we derive the closed-form expressions for the connection outage probability and the secrecy outage probability to characterize the reliability and the security performance, respectively. And we determine the optimal power allocation factor and wiretap code rates which maximize the secrecy throughput of the wiretap channel under secrecy outage probability constraint.
This paper studies the physical layer security (PLS) in an underlay cognitive radio (CR) network. Under an interference constraint set by the primary user, we propose a secure transmission scheme from a secondary source to a secondary destination in the presence of spatially random eavesdroppers, the distribution of which is modeled as a homogeneous Possion point process (PPP). In addition to transmitting the message signal, the secondary source is allowed to use part of its power to transmit jamming signals in order to interfere the eavesdroppers. Assuming that the secondary destination has the knowledge of the jamming signals, we derive the closed-form expression for the connection outage probability and an easy-to-compute expression for the secrecy outage probability to characterize the reliability and the security performance, respectively. Moreover, we determine the optimal power allocation factor and wiretap code rates which maximize the secrecy throughput of the wiretap channel under secrecy outage probability constraint.
We propose a secure transmission scheme for a relay wiretap channel, where a source communicates with a destination via a decode-and- forward relay in the presence of spatially random- distributed eavesdroppers. We assume that the source is equipped with multiple antennas, whereas the relay, the destination, and the eavesdroppers are equipped with a single antenna each. In the proposed scheme, in addition to information signals, the source transmits artificial noise signals in order to confuse the eavesdroppers. With the target of maximizing the secrecy throughput of the relay wiretap channel, we derive a closed-form expression for the transmission outage probability and an easy-to-compute expression for the secrecy outage probability. Using these expressions, we determine the optimal power allocation factor and wiretap code rates that guarantee the maximum secrecy throughput, while satisfying a secrecy outage probability constraint. Furthermore, we examine the impact of source antenna number on the secrecy throughput, showing that adding extra transmit antennas at the source brings about a significant increase in the secrecy throughput.
We propose a secure transmission scheme for a wiretap channel, where a source transmits to a legitimate destination in the presence of a full- duplex eavesdropper. We assume that the full- duplex eavesdropper performs both eavesdropping and malicious jamming simultaneously. In order to combat the full-duplex active eavesdropper, the source transmits artificial noise (AN) signals, apart from information signals, to confuse the eavesdropper. We adopt the hybrid outage probability as the performance metric, which takes both the transmission outage probability and the secrecy outage probability into consideration. We derive a compact expression for the hybrid outage probability. Utilizing the derived expression, we determine the optimal power allocation factor between information signals and AN signals that minimizes the hybrid outage probability. We also examine the asymptotic hybrid outage probability in the high signal-to-noise ratio regime. Furthermore, we compare the secrecy performance achieved by a full-duplex active eavesdropper with that achieved by a passive eavesdropper, showing that active eavesdropping can be more harmful to the legitimate system.
In this paper, for the conventional MISO wiretap channel, we take into account the locations' random nature regarding those eavesdroppers and the ambient interferers in the wireless networks. For the convenience of mathematical analysis, these location distributions are modeled as Poisson point processes (PPPs). We assume that the transmitter Alice has no channel state information (CSI) about the other nodes except that it knows the statistical CSI of links about the legitimate user Bob and those eavesdroppers. In order to improve the security of Bob, we further set up a protected zone (PZ) to prevent excessive eavesdroppers from overhearing confidential signals. We investigate the probabilities of connection outage and secrecy outage to derive the closed form expression of secrecy transmission rate. Afterwards, we formulate an secrecy rate maximization problem and solve it to determine the optimized beamforming vector. The numerical results reveal the superiority of the proposed beamforming optimization over the relevant eigen beamforming design in [1].
We design a new relay-aided secure transmission scheme, in which a source communicates with a destination through a trusted decode-and-forward relay in the presence of spatially random-distributed non-colluding eavesdroppers. We consider a general antenna configuration, in which the source, relay, destination, and eavesdroppers are equipped with multiple antennas. We assume that both the source and the relay transmit artificial noise signals in addition to information signals. We also assume that the source and the relay adopt different codebooks, and that the transmitted signals from the source and relay are not jointly processed at each eavesdropper. We first derive a closed-form expression for the transmission outage probability and a new expression for the secrecy outage probability. Notably, these expressions are valid for an arbitrary number of antennas at the source, relay, and destination. We then derive simple yet valuable expressions for the asymptotic transmission outage probability and the asymptotic secrecy outage probability, which reveal the secrecy performance when the number of antennas at the source grows sufficiently large. Using our expressions, we quantify a practical performance metric, namely, the secrecy throughput, under a secrecy outage probability constraint. We further determine the system and channel parameters that maximize the secrecy throughput, leading to analytical security solutions suitable for real-world deployment.
This paper investigates cooperative security in wireless networks, where a source (Alice) intends to transmit a confidential message to a legitimate destination (Bob), with the help of a cooperative jammer (Charlie), coexisting with multiple passive eavesdroppers (Eves). In particular, by assuming knowledge of Bob's perfect channel state information (CSI) but only Eves’ statistical CSIs, secrecy beamforming with artificial noise (AN) is utilized for secure transmission, and cooperative jamming (CJ) is explored to further enhance secrecy. We first derive an accurate closed-form expression for the secrecy outage probability (SOP), and establish the condition under which positive secrecy rate is achievable. Then, we provide a secure transmit design for maximizing the SOP constrained secrecy rate. Moreover, based on a strict mathematical analysis, we characterize the impact of the main channel quality and the number of Eves on transmit design and secrecy performance. Specifically, optimal power allocation ratio between the information-bearing signal and the AN signal increases as the main channel quality improves, and decreases with the number of Eves. Numerical results confirm that our design achieves performance improvement in terms of both secrecy rate and secure energy efficiency, as compared to the approach without CJ.