In this paper, the weighted fractional Fourier transform (WFRFT) signal domain is introduced to enhance the security performance of two-way trusted relay systems at the signal level. The proposed scheme, which requires only a single relay node, leverages the multi-component energy distribution characteristics of WFRFT signals to improve security with low complexity and high power efficiency. The inherent security mechanism of WFRFT analyzed in this paper can be simply summarized as follows: the superposition of components in WFRFT signals that do not satisfy specific constraints will result in the inability to perfectly reconstruct the message signal. Based on this, confidential information is encoded into WFRFT signals with private transform orders, allowing legitimate users to achieve perfect decoding. Since WFRFT signals exhibit energy concentration only in specific transformation domains, mismatched transform orders adopted by the eavesdropper cause energy loss in the information-bearing signal, leading to inter-component interference that further degrades the quality of the recovered signal. The advantages of the proposed scheme in limiting information leakage and improving the achievable secrecy sum rate (SSR) are analyzed. Numerical results validate the theoretical analysis and demonstrate the secrecy performance of the proposed scheme.
In this paper, the weighted fractional Fourier transform (WFRFT) signal domain is introduced to enhance the security performance of two-way trusted relay systems at the signal level. The proposed scheme, which requires only a single relay node, leverages the multi-component energy distribution characteristics of WFRFT signals to improve security with low complexity and high power efficiency. The inherent security mechanism of WFRFT analyzed in this paper can be simply summarized as follows: the superposition of components in WFRFT signals that do not satisfy specific constraints will result in the inability to perfectly reconstruct the message signal. Based on this, confidential information is encoded into WFRFT signals with private transform orders, allowing legitimate users to achieve perfect decoding. Since WFRFT signals exhibit energy concentration only in specific transformation domains, mismatched transform orders adopted by the eavesdropper cause energy loss in the information-bearing signal, leading to inter-component interference that further degrades the quality of the recovered signal. The advantages of the proposed scheme in limiting information leakage and improving the achievable secrecy sum rate (SSR) are analyzed. Numerical results validate the theoretical analysis and demonstrate the secrecy performance of the proposed scheme.
This paper proposes a Weighted fractional Fourier transform (WFRFT) based cooperation scheme to improve PHY layer security against eavesdropping in wireless communications. Rather than dissipating valuable transmission power to jam the eavesdropper, by leveraging the features of WFRFT, the information bearing signal can create “Artificial Noise” effect at the eavesdropper while imposing no effect on the legitimate receiver. Specifically, the proposed WFRFT based cooperation is performed in a two-phase manner, whereby the source first broadcasts its message to the intermediate nodes which then perform WFRFT operation to relay the message to the destination, with the objective of boosting the secrecy rate of the source-destination pair. Simulation results are provided, which demonstrate that the WFRFT-based user cooperation scheme can acehieve a significant performance gain, in terms of secrecy ergodic capacity, compared with conventional security-oriented user cooperation schemes.
In this letter, we investigate secure communication for the downlink rate-splitting multiple access (RSMA) system by integrating both the spatial domain and weighted fractional Fourier transform (WFRFT) signal domain to enhance its physical layer security (PLS) performance. To counter the external passive eavesdropper, we propose an RSMA-CM-WFRFT scheme to promote the dual use of the common message (CM), thereby improving the secrecy rate of both common and private messages. Specifically, the common message is encoded based on WFRFT, enabling all received power of legitimate users for signal reconstruction, while introducing inter-component interference at the eavesdropper. Furthermore, the inevitable serial interference caused by the WFRFT-encoded CM sequence overlays onto the private message (PM), thus enhancing its security. To counter internal eavesdroppers, we propose an RSMA-PM-WFRFT scheme to achieve parallel encryption by encoding the private message of different users into different WFRFT domains. Additionally, we formulate and solve a non-convex optimization problem aimed at minimizing the required power under both security and reliability constraints. Numerical results demonstrate the superior performance of the two proposed schemes.
A novel physical layer security transmission scheme for relay-assisted systems is proposed, utilizing the generalized weighted fractional Fourier transform (GWFRFT). This scheme introduces a multi-component approach to enhance secure transmission, where signals are decomposed into four components with equal power distribution. Different signal components are transmitted by different relay nodes, resulting in the destination and eavesdroppers receiving a superposition of four non-orthogonal signal components. Precoding, combined with the self-interference properties of the components, significantly reduces the achievable rate of the eavesdropping channel, enhancing the secrecy rate. This scheme reduces the performance of eavesdroppers without additional power consumption or computational complexity. The results demonstrate improved security performance and reduced energy consumption compared to artificial noise-based secure transmission methods.
In this paper, we propose a novel user cooperation scheme based on weighted fractional Fourier transform (WFRFT), to enhance the physical (PHY) layer security of wireless transmissions against eavesdropping. Specifically, instead of dissipating additional transmission power for friendly jamming, by leveraging the features of WFRFT, the information bearing signal of cooperators can create an identical artificial noise effect at the eavesdropper while causing no performance degradation on the legitimate receiver. Furthermore, to form the cooperation set in an autonomous and distributed manner, we model WFRFT-based PHY-layer security cooperation problem as a coalitional game with non-transferable utility. A distributed merge-and-split algorithm is devised to facilitate the autonomous coalition formation to maximize the security capacity while accounting for the cooperation cost in terms of power consumption. We analyze the stability of the proposed algorithm and also investigate how the network topology efficiently adapts to the mobility of intermediate nodes. Simulation results demonstrate that the WFRFT-based user cooperation scheme leads to a significant performance advantage, in terms of secrecy ergodic capacity, compared with the conventional security-oriented user cooperation schemes, such as relay-jamming and cluster-beamforming.
In this paper, a weighted fractional Fourier transform (WFRFT) based cooperative overlay system, aiming to guarantee physical layer (PHY) security, is proposed. The paper elaborates how WFRFT and physical layer properties of the wireless medium are collaborated to guarantee the secrecy of wireless transmissions. In the proposed system, WFRFT is first preform on the secret data, such that the transmitted signal is distorted and can only be neutralized by inverse-WFRFT with the same parameter. And then two streams of the transformed sequences that bearing different messages are cooperatively and simultaneously transmitted to two legitimate receivers via a beamforming-liked method, respectively. In general, both the rapid spatial decorrelation property and the inherent security features of WFRFT are leveraged, such that only the eavesdropper's is degraded, and hence, the wireless communication secrecy is reliably guaranteed. Numerical simulations are conducted to evaluate the performance of the proposed system in terms of the average bit error rate and the secrecy capacity.
In this paper, a weighted fractional Fourier transform(WFRFT) based cooperative overlay system, aiming to guarantee physical layer(PHY) security, is proposed. The paper elaborates how WFRFT and physical layer properties of the wireless medium are collaborated to guarantee the secrecy of wireless transmissions. In the proposed system, WFRFT is first preform on the secret data, such that the transmitted signal is distorted and can only be neutralized by inverse-WFRFT with the same parameter. And then two streams of the transformed sequences that bearing different messages are cooperatively and simultaneously transmitted to two legitimate receivers via a beamforming-liked method, respectively. In general, both the rapid spatial decorrelation property and the inherent security features of WFRFT are leveraged, such that only the eavesdropper’s is degraded, and hence, the wireless communication secrecy is reliably guaranteed. Numerical simulations are conducted to evaluate the performance of the proposed system in terms of the average bit error rate and the secrecy capacity.