In this paper, we investigate the physical layer security of single amplify-and-forward (AF) relay communication system based on compressed sensing (CS). Different to the traditional method by compressing the source data with a specific measurement matrix (e.g. Gaussian matrix)to achieve security, we first demonstrate that the combination matrix of the compression measurement matrix and cooperative AF channel matrix between legitimate nodes (source, relay, and destination) can be considered as a secure measurement matrix for physical layer security. Compared with CS scenario without AF (CS Non-AF), the eavesdropper in the proposed scheme can hardly decode the original data correctly even when it has a perfect knowledge of eavesdropper channel state information (ECSI). The robustness of the scheme in the presence of one eavesdropper is also investigated.
In this paper, we investigate the physical layer security of single amplify-and-forward (AF) relay communication system based on compressed sensing (CS). Different to the traditional method by compressing the source data with a specific measurement matrix (e.g. Gaussian matrix)to achieve security, we first demonstrate that the combination matrix of the compression measurement matrix and cooperative AF channel matrix between legitimate nodes (source, relay, and destination) can be considered as a secure measurement matrix for physical layer security. Compared with CS scenario without AF (CS Non-AF), the eavesdropper in the proposed scheme can hardly decode the original data correctly even when it has a perfect knowledge of eavesdropper channel state information (ECSI). The robustness of the scheme in the presence of one eavesdropper is also investigated.
In this letter, we consider secure communication of one source-destination pair with multi-hop amplify-and-forward relays. We utilize compressed sensing (CS) to guarantee the CS multi-hop network security. Different to the most existed works, we first demonstrate that the time slots during the whole transmission can be regarded as the measurement dimension in CS. Therefore, the physical layer security can be achieved by multi-hop cooperative wireless transmission whose equivalent channel matrix can be used as the secure measurement matrix. Increasing the number of hops will increase the secrecy rate. We also investigate the robustness of the CS multi-hop scheme in the presence of one eavesdropper.
Energy harvesting (EH) has attracted a lot of attention in cooperative communication networks studies for its capability of transferring energy from sources to relays. In this paper, we study the secrecy capacity of a cooperative compressed sensing amplify and forward (CCS-AF) wireless network in the presence of eavesdroppers based on an energy harvesting protocol. In this model, the source nodes send their information to the relays simultaneously, and then the relays perform EH from the received radio-frequency signals based on the power splitting-based relaying (PSR) protocol. The energy harvested by the relays will be used to amplify and forward the received information to the destination. The impacts of some key parameters, such as the power splitting ratio, energy conversion efficiency, relay location, and the number of relays, on the system secrecy capacity are analyzed through a group of experiments. Simulation results reveal that under certain conditions, the proposed EH relaying scheme can achieve higher secrecy capacity than traditional relaying strategies while consuming equal or even less power.
In this paper, we assess the physical-layer secrecy performance of the amplify-and-forward compressed sensing (AF-CS) framework when malicious eavesdropping nodes are listening. In particular, we investigate the robustness of the AF-CS scheme in the presence of a group of coordinated eavesdropping nodes under the assumption that they have corrupted channel state information. In order to fulfil this assumption, we propose a channel estimation technique based on pseudorandom pilots. This technique introduces extra uncertainty only in the channel estimation of the eavesdroppers. Our simulation results evaluate the physical-layer protection as a function of the total number of coordinated eavesdroppers and the level of channel estimation distortion of the eavesdroppers. We demonstrate that a small number of eavesdroppers (small being defined later on) has a zero probability of recovering the intended signal. We also show that a very large number of eavesdropping nodes are required to perfectly recover the signal in comparison with other distributed compressed sensing schemes in the literature.
The physical layer security technology is an effective way to reduce information leakage in a wireless communication system. In this paper, we study the physical-layer security of one-way wiretap channel which contains a source-destination pair, an eavesdropper and multiple cooperating relay nodes. What's more, in this channel, there exists direct link between the source and the destination (eavesdropper) and lacks he eavesdropper's channel state information (ECSI). To address its physical-layer security, we proposed a scheme which combines amplify-and-forward (AF)-based relay beamforming and cooperation jamming (CJ) technology. We aim at minimizing the power available for transmitting desired information in relays and optimizing the relay weights under the scenario of limiting the signal to ratio at the destination to a given range, which can be solved by convex optimization techniques. After that, we prove that the optimization results are unique and globally optimum. And the numerical results show that the proposed design can effectively enhance secure transmission rate.
Physical (PHY) layer security approaches for wireless communications can prevent eavesdropping without upper layer data encryption. However, they are hampered by wireless channel conditions: absent feedback, they are typically feasible only when the source-destination channel is better than the source-eavesdropper channel. Node cooperation is a means to overcome this challenge and improve the performance of secure wireless communications. This paper addresses secure communications of one source-destination pair with the help of multiple cooperating relays in the presence of one or more eavesdroppers. Three cooperative schemes are considered: decode-and-forward (DF), amplify-and-forward (AF), and cooperative jamming (CJ). For these schemes, the relays transmit a weighted version of a reencoded noise-free message signal (for DF), a received noisy source signal (for AF), or a common jamming signal (for CJ). Novel system designs are proposed, consisting of the determination of relay weights and the allocation of transmit power, that maximize the achievable secrecy rate subject to a transmit power constraint, or, minimize the transmit power subject to a secrecy rate constraint. For DF in the presence of one eavesdropper, closed-form optimal solutions are derived for the relay weights. For other problems, since the optimal relay weights are difficult to obtain, several criteria are considered leading to suboptimal but simple solutions, i.e., the complete nulling of the message signals at all eavesdroppers (for DF and AF), or the complete nulling of jamming signal at the destination (for CJ). Based on the designed relay weights, for DF in the presence of multiple eavesdroppers, and for CJ in the presence of one eavesdropper, the optimal power allocation is obtained in closed-form; in all other cases the optimal power allocation is obtained via iterative algorithms. Numerical evaluation of the obtained secrecy rate and transmit power results show that the proposed design can significantly improve the performance of secure wireless communications.
Cooperative relaying is an effective technology to improve the capacity of physical-layer security, in which the relay helps forward the received signal to the destination. In this paper, a cooperative compressive sensing and amplify-and-forward (CCS-AF) scheme, which combines the compressive sensing theory and amplify-and-forward strategy, is proposed to increase the secrecy capacity. To optimize the secrecy performance, a coalition formation algorithm based on coalitional game theory of optimal relay selection is proposed to maximize the secrecy capacity. Different to maximizing the individual utility based on the traditional pareto order, the max-coalition order rule is newly defined to guide the coalitional formation. Simulation results indicate that with the proposed algorithm, part of the relays could form a coalition to forward the information and the proposed algorithm could significantly improve the secrecy capacity of cooperative multi-relay networks.