We consider the problem of security in wireless multicasting for a multiple-input multiple-output (MIMO) relay-aided system. The network suffers from a group of adaptive eavesdroppers who can act as both simple eavesdroppers and hostile jammers. This paper formulates the impact of friendly jammers to improve secured communication. We derived the expressions for secrecy multicast capacities considering the absence and presence of friendly jammers. The best relay for transmission is chosen from a group of relays that aids to achieve the maximum secrecy capacity while the best jammer is selected based on competitive interference price. Numerical results show that the achievable secrecy multicast capacity increases significantly in the presence of jammer to nullify the effect of adversaries. Results under different scenarios of varying jamming and relay powers demonstrate the efficacy of friendly jammers in providing physical layer security.
We consider the problem of security in wireless multicasting for a multiple-input multiple-output (MIMO) relay-aided system. The network suffers from a group of adaptive eavesdroppers who can act as both simple eavesdroppers and hostile jammers. This paper formulates the impact of friendly jammers to improve secured communication. We derived the expressions for secrecy multicast capacities considering the absence and presence of friendly jammers. The best relay for transmission is chosen from a group of relays that aids to achieve the maximum secrecy capacity while the best jammer is selected based on competitive interference price. Numerical results show that the achievable secrecy multicast capacity increases significantly in the presence of jammer to nullify the effect of adversaries. Results under different scenarios of varying jamming and relay powers demonstrate the efficacy of friendly jammers in providing physical layer security.
In this paper, we consider the problem of information theoretic security for a single-input single-output (SISO) relay-aided network in the presence of an adaptive eavesdropper. We assess the impact of deceptive friendly jammers on the secrecy of communication in this network when countering adaptive eavesdroppers. Specifically, we derive the secrecy capacity and secrecy outage probability of the network and compare the results in the absence and presence of a deceptive friendly jammer. Our results show that the secrecy capacity of the network increases while the achievable secrecy outage probability decreases significantly in the presence of friendly jammer to nullify the effect of the adversary. Numerical results, obtained through computer simulations, under different scenarios of varying jamming power and average main channel gain to average eavesdropper channel gain ratio demonstrate the effectiveness of friendly jammer in providing physical layer security.
We consider the problem of secure wireless multicasting through multiple-input multiple-output (MIMO) radio system in which two co-existing users communicate with two groups of receivers in the presence of multiple eavesdroppers. At first, we calculate the secrecy multicast capacity of each group and investigate the impact of interferences on it. We also quantify the loss of secrecy multicast capacity due to interferences. Then, we use zero-forcing (ZF) precoding at a relay to enhance the secrecy multicast capacity of each group by eliminating interferences. Finally, we propose a scheme to improve the secrecy multicast capacity of each group making use of interference energy that already exists in the communication medium employing selective precoding at the relay. In the proposed scheme, interference provides an additional source of energy that enhances secrecy multicast capacity at each group without the need to increase the transmitted power. Our results show that exploiting free interference power, the performance of co-existing wireless multicasting can be improved without affecting the performance of each other.
We consider the problem of secure wireless multicasting through multiple-input multiple-output (MIMO) radio system in which two co-existing users communicate with two groups of receivers in the presence of multiple eavesdroppers. At first, we calculate the secrecy multicast capacity of each group and investigate the impact of interferences on it. Then, we use zero-forcing (ZF) precoding at a relay to enhance the secrecy multicast capacity of each group removing the impact of interferences. Finally, we propose a scheme to improve the secrecy multicast capacity of each group making use of interference energy that already exists in the communication medium employing selective precoding at the relay. In the proposed scheme, interference provides an additional source of energy that enhances secrecy multicast capacity at each group without the need to increase the transmitted power. Our results show that exploiting free interference power, the performance of coexisting wireless multicasting can be improved without affecting the performance of each other.
Recently, physical layer security has been recognized as a new design paradigm to provide security in wireless networks. In contrast to the existing conventional cryptographic methods, physical layer security exploits the dynamics of fading channels to enhance security of wireless communications. This paper studies optimization frameworks for a multicasting network in which a transmitter broadcasts the same information to a group of legitimate users in the presence of multiple eavesdroppers. In particular, power minimization and secrecy rate maximization problems are investigated for a multicasting secrecy network. First, the power minimization problem is solved for different numbers of legitimate users and eavesdroppers. Next, the secrecy rate maximization problem is investigated with the help of private jammers to improve the achievable secrecy rates through a game theoretic approach. These jammers charge the transmitter for their jamming services based on the amount of interference caused to the eavesdroppers. For a fixed interference price scenario, a closed-form solution for the optimal interference requirement to maximize the revenue of the transmitter is derived. This rate maximization problem for a nonfixed interference price scenario is formulated as a Stackelberg game in which the jammers and transmitter are the leaders and follower, respectively. For the proposed game, a Stackelberg equilibrium is derived to maximize the revenues of both the transmitter and the private jammers. To support the derived theoretical results, simulation results are provided with different numbers of legitimate users and eavesdroppers. In addition, these results show that physical layer security based jamming schemes could be incorporated in emerging and future wireless networks to enhance the quality of secure communications.
In this paper, the security of two-phase relaying system with multiple intermediate nodes in the presence of a malicious eavesdropper is investigated. To enhance the secrecy, a joint cooperative beamforming and jamming combined with relay and jammer selection is proposed. First, the source broadcasts its signal to the relays that are located close to source in a cluster, i.e., the source node uses a small amount of power to broadcast its message locally to other nodes of the cluster, while destination and the eavesdropper are located outside this cluster. In the second phase, two relays transmit re-encoded signal with optimal beamforming such that the secrecy rate is maximized. Simultaneously, two other intermediate nodes (which act as friendly jammers) transmit random jamming signals to degrade the eavesdropper’s channel. Our goal in this paper is to maximize the secrecy rate by applying different methods such as cooperative beamforming, cooperative jamming and relay and jammer selection. To avoid operational complexity, we consider the minimum number of intermediate nodes needed for relaying and jamming without losing the performance, i.e., achieving a non-zero secrecy rate. Cooperative beamforming with multiple relays demands high amount of information exchange and therefore increases the operational complexity. Thus, we aim to reduce the number of relays which take part in cooperative beamforming. Limiting the number of relays may have a bad effect on the coding gain which we compensate it with a proposed selection gain scheme. Numerical results demonstrate the advantage of our proposed scheme compared to the scheme with no cooperative jamming. The main contribution of this work is combining cooperative beamforming and jamming with relay and jammer selection to enhance the physical layer security.
To improve physical (PHY) layer security of a wireless relay system in the presence of an eavesdropper, a two-phase cooperative relaying scheme is investigated in this paper. In phase I, the source transmits confidential message, simultaneously, it cooperates with the friendly jammers and destination to create jamming signal at the eavesdropper without affecting the forwarding relay which is preselected. In phase II, the forwarding relay retransmits the decoded signal, meanwhile, the particular relay cooperates with the friendly jammers to create jamming signal at the eavesdropper without affecting the destination. We focus on the investigation of optimal power allocation for maximizing achievable secrecy rate subject to a total power constraint. Optimal relay selection and suboptimal relay selection schemes are also proposed. It is shown that as the number of relays increases, both secrecy rate and the performance of suboptimal relay selection scheme improve significantly. Numerical results are presented to validate the derived analytical results and compare them to existing work.