Biblio

In this paper, a novel strategy of relay selection and cooperative jammer beamforming is proposed. The proposed scheme selects one node from the intermediate nodes as relay and the rest nodes as friendly jammers. The relay operates in amplify-and-forward (AF) strategy. Jammer weights are derived to null the jamming signals at the destination and relay node and maximize the jamming signal at the eavesdropper. Furthermore, a closed-form optimal solution of power allocation between the selected relay and cooperative jammers is derived. Numerical simulation results show that the proposed scheme can outperform the conventional schemes at the same power consumption.

Considered is a network of parallel wireless channels in which individual parties are engaged in secret communication under the protection of cooperative jamming. A strategic eavesdropper selects the most vulnerable channels to attack. Existing works usually suggest the defender allocate limited cooperative jamming power to various channels. However, it usually requires some strong assumptions and complex computation to find such an optimal power control policy. This paper proposes a probabilistic cooperative jamming scheme such that the defender focuses on protecting randomly selected channels. Two different cases regarding each channel’s eavesdropping capacity are discussed. The first case studies the general scenario where each channel has different eavesdropping capacity. The second case analyzes an extreme scenario where all channels have the same eavesdropping capacity. Two non-zero-sum Nash games model the competition between the network defender and an eavesdropper in each case. Furthermore, considering the case that the defender does not know the eavesdropper’s channel state information (CSI) leads to a Bayesian game. For all three games, we derive conditions for the existence of a unique Nash equilibrium (NE), and obtain the equilibria and the value functions in closed form.

In this paper, we study covert communications between a pair of legitimate transmitter-receiver against a watchful warden over slow fading channels. There coexist multiple friendly helper nodes who are willing to protect the covert communication from being detected by the warden. We propose an uncoordinated jammer selection scheme where those helpers whose instantaneous channel gains to the legitimate receiver fall below a pre-established selection threshold will be chosen as jammers radiating jamming signals to defeat the warden. By doing so, the detection accuracy of the warden is expected to be severely degraded while the desired covert communication is rarely affected. We then jointly design the optimal selection threshold and message transmission rate for maximizing covert throughput under the premise that the detection error of the warden exceeds a certain level. Numerical results are presented to validate our theoretical analyses. It is shown that the multi-jammer assisted covert communication outperforms the conventional single-jammer method in terms of covert throughput, and the maximal covert throughput improves significantly as the total number of helpers increases, which demonstrates the validity and superiority of our proposed scheme.

The environment of wireless sensor networks (WSNs) makes the communication not only have the broadcast nature of wireless transmission, but also be limited to the low power and communication capability of sensor equipment. Both of them make it hard to ensure the confidentiality of communication. In this paper, we propose a cluster-based cooperative jamming scheme based on physical layer security for WSNs. The mathematical principle of the scheme is based on the design principle of code division multiple access. By using the orthogonality of orthogonal vectors, the legitimate receiver can effectively eliminate the noise, which is generated by the cooperative jamming nodes to disturb the eavesdropper. This scheme enables the legitimate receiver to ensure a strong communication confidentiality even if there is no location or channel advantage comparing with eavesdroppers. Through extensive simulations, the security performance of the proposed scheme is investigated in terms of secrecy rate.

This paper considers the two-user interference relay channel where each source wishes to communicate to its destination a message that is confidential from the other destination. Furthermore, the relay, that is the enabler of communication, due to the absence of direct links, is untrusted. Thus, the messages from both sources need to be kept secret from the relay as well. We provide an achievable secure rate region for this network. The achievability scheme utilizes structured codes for message transmission, cooperative jamming and scaled compute-and-forward. In particular, the sources use nested lattice codes and stochastic encoding, while the destinations jam using lattice points. The relay decodes two integer combinations of the received lattice points and forwards, using Gaussian codewords, to both destinations. The achievability technique provides the insight that we can utilize the untrusted relay node as an encryption block in a two-hop interference relay channel with confidential messages.