In this paper, we consider the design of a new secrecy transmission scheme for a four-node relay-eavesdropper channel. The key idea of the proposed scheme is to combine noisy network coding with the interference assisted strategy for wiretap channel with a helping interferer. A new achievable secrecy rate is characterized for both discrete memoryless and Gaussian channels. Such a new rate can be viewed as a general framework, where the existing interference assisted schemes such as noisy-forwarding and cooperative jamming approaches can be shown as special cases of the proposed scheme. In addition, under some channel condition where the existing schemes can only achieve zero secrecy rate, the proposed secrecy scheme can still offer significant performance gains.
In this paper, we consider the design of a new secrecy transmission scheme for a four-node relay-eavesdropper channel. The key idea of the proposed scheme is to combine noisy network coding with the interference assisted strategy for wiretap channel with a helping interferer. A new achievable secrecy rate is characterized for both discrete memoryless and Gaussian channels. Such a new rate can be viewed as a general framework, where the existing interference assisted schemes such as noisy-forwarding and cooperative jamming approaches can be shown as special cases of the proposed scheme. In addition, under some channel condition where the existing schemes can only achieve zero secrecy rate, the proposed secrecy scheme can still offer significant performance gains.
This paper study information-theoretic security for a four-node relay-eavesdropper channel. We propose a new achievable scheme whose key idea is to combine noisy network coding for relay channels and the interference assisted strategy for wiretap channel with a helping interferer. The corresponding achievable secrecy rate is characterized for both discrete memoryless and Gaussian channels. The previous interference assisted schemes such as noise-forwarding and cooperative jamming are shown to be special cases of the proposed scheme. Moreover, in some very strong eavesdropping case where these interference assisted schemes can only achieve zero secrecy rate, the proposed secrecy scheme can still achieve a positive secrecy rate.
In this paper, we consider the design of a new secure transmission scheme for a four-node relay-eavesdropper channel, where user cooperation is used to facilitate secure communications. The key idea of the proposed achievable scheme is to apply the compression relaying concept of noisy network coding (NNC) to the secrecy communication scenario. But different from the original non-secrecy NNC, the compression rate at the relay is adaptively chosen according to the eavesdropping channel. Particularly, helping interference information is injected into the compression codebook at the relay by simply enlarging the compression rate, which is to effectively suppress the eavesdropping channel. Closed-form expressions of the secrecy rates achieved by the proposed NNC-based secure scheme are characterized for both the discrete memoryless and Gaussian relay-eavesdropper channels, where the optimal compression rate and the optimal transmit power at the relay are also determined. The proposed secure scheme can be viewed as a general framework, which naturally combines the NNC compression relaying scheme with the interference-assisted scheme. Analytical and numerical results demonstrate that the proposed secure scheme offers constant performance gains over typical existing cooperative secure schemes.
This paper considers the four-node relay-eavesdropper channel, where a relay node helps the source to send secret messages to the destination in the presence of a passive eavesdropper. For the discrete memoryless case, we propose a hybrid cooperative coding scheme, which is based on the combination of the partial decode-forward scheme, the noise-forward scheme and the random binning scheme. The key feature of the proposed hybrid cooperative scheme is that the relay integrates the explicit cooperation strategy and the implicit cooperation strategy by forwarding source messages and additional interference at the same time. The derived achievable secrecy rate shows that some existing works can be viewed as special cases of the proposed scheme. Then, the achievable secrecy rate is extended to the Gaussian channel based on Gaussian codebooks, and the optimal power policy is also identified in the high power region. Both the analysis and numerical results are provided to demonstrate that the proposed hybrid cooperative coding scheme outperforms the comparable ones, especially in the high power region.
The prominence of the wireless communication has been urging the monotonically increasing demand of security and privacy. In wireless systems, the notion of perfect secrecy of information with respect to illegitimate nodes can be ensured via physical layer security (PLS) techniques. Unfortunately, they can be made less effective if source- eavesdropper wiretap channel is better than the main source-receiver channel. The various node cooperation schemes can be employed to combat this limitation where a relay node assists the communication to improve the performance significantly. In this paper, a four node wireless communication system consisting of a source, a destination, a relay and an eavesdropper as wire-tapper has been considered. The performance of the traditional cooperation schemes in terms of secrecy rate has been investigated with a different scenario where relay node helps the eavesdropper to deteriorate the secrecy rate. In addition, since legitimate receiver can overhear the transmission of relay, it favours the achievable secrecy rate. We formulate an analytical expression of conditional secrecy outage probability for the investigated system. From the obtained simulation results, it has been observed that secrecy rate is monotonically increases with path loss index. Furthermore, the proper selection of the system parameters leads to enhance the secrecy performance of the system even if relay pertains to degrade the performance. Amplify-and-forward, cooperation, decode-and-Forward, secrecy rate, relay.
A simple four node network in which cooperation improves the information-theoretic secrecy is studied. The channel consists of two senders, a receiver, and an eavesdropper. One or both senders transmit confidential messages to the receiver, while the eavesdropper tries to decode the transmitted message. The main result is the derivation of a newly achievable rate-equivocation region that is shown to be larger than a rate-equivocation region derived by Lai and El Gamal for the relay-eavesdropper channel. When the rate of the helping interferer is zero, the new rate-equivocation region reduces to the capacity-equivocation region over the wire-tap channel, hence, the new achievability scheme can be seen as a generalization of a coding scheme proposed by Csiszar and Korner. This result can naturally be combined with a rate-equivocation region given by Tang et al. (for the interference assisted secret communication), yielding an even larger achievable rate-equivocation region.
In this paper, we consider a secrecy relaying communication scenario where all nodes are equipped with multiple antennas. An eavesdropper has the access to the global channel state information (CSI), and all the other nodes only know the CSI not associated with the eavesdropper. A new secrecy transmission protocol is proposed, where the concept of interference alignment is combined with cooperative jamming to ensure that artificial noise from transmitters can be aligned at the destination, but not at the eavesdropper due to the randomness of wireless channels. Analytical results, such as ergodic secrecy rate and outage probability, are developed, from which more insightful understanding of the proposed protocol, such as multiplexing and diversity gains, can be obtained. A few special cases, where outage probability cannot be decreased to zero regardless of SNR, are also discussed. Simulation results are provided to demonstrate the performance of the proposed secrecy transmission protocol.