In this paper, a secure generalised precoding aided quadrature spatial modulation (SGPQSM) scheme is proposed to resist the passive eavesdropping that is unknown to the transmitter. With the help of artificial noise in the null space, the SGPQSM scheme can retain all the advantages of generalised precoding aided quadrature spatial modulation (GPQSM) at the legitimate receiver while producing interference to the eavesdropper. Signal space diversity (SSD) is also used to increase the "diversity order". Then the secrecy capacity of our proposed SGPQSM is analyzed and the optimal power allocation between signal and artificial noise is investigated. Simulation results demonstrate that our SGPQSM can significantly improve the secrecy performance. In multiple-input multiple-output systems, the proposed SGPQSM scheme performs better than the existing secure scheme.
In this paper, a secure generalised precoding aided quadrature spatial modulation (SGPQSM) scheme is proposed to resist the passive eavesdropping that is unknown to the transmitter. With the help of artificial noise in the null space, the SGPQSM scheme can retain all the advantages of generalised precoding aided quadrature spatial modulation (GPQSM) at the legitimate receiver while producing interference to the eavesdropper. Signal space diversity (SSD) is also used to increase the "diversity order". Then the secrecy capacity of our proposed SGPQSM is analyzed and the optimal power allocation between signal and artificial noise is investigated. Simulation results demonstrate that our SGPQSM can significantly improve the secrecy performance. In multiple-input multiple-output systems, the proposed SGPQSM scheme performs better than the existing secure scheme.
To resist the passive eavesdropping while reserving the same hardware cost and receiver structure of the legitimate receiver, a secure quadrature spatial modulation (QSM) scheme is proposed in this letter. Instead of the information symbol, a mixture of the information symbol and artificial noise is transmitted through the activated transmit antennas. The mixed signals are designed, so that the artificial noise is cancelled at the legitimate receiver but cause random interference to the eavesdropper. The secrecy rate is analyzed and the optimal power allocation between the artificial noise and the information signal is investigated. The influence of the number of the eavesdropper's antennas is discussed. Simulation results show that, for multiple-input-single-output systems, the proposed secure QSM scheme achieves the best secrecy performance among the existing similar schemes by using less radio frequency chains. For multiple-input-multiple-output systems, the secure QSM scheme performs better than the existing secure SM scheme does under the same power constraint and transmission rate.
In this letter, the precoding-aided spatial modulation (PSM) is generalized to a secret PSM (SPSM) scheme, which has the capability to resist malicious eavesdropping from an eavesdropper that is unknown to the transmitter. We design a time-varying precoder for the SPSM so that it can retain all the PSM's advantages at the desired receiver while producing time-varying interference to the eavesdropper. The secrecy capacity of our proposed SPSM is studied, and the optimal power allocation between signal and interference transmission is investigated. Our studies and performance results demonstrate that our SPSM can significantly improve the secrecy performance of the PSM, particularly in a high-signal-to-noise-ratio region. Furthermore, the SPSM is capable of achieving a nonzero secrecy rate even when the eavesdropper has more antennas than the desired receiver.
In this paper, a physical layer security (PLS) scheme based on quadrature channel modulation (QCM) called secure QCM (SQCM) is proposed for time division duplex (TDD) multi-input multi-output (MIMO) media based modulation (MBM) systems to resist eavesdropping. By exploiting the abundant legitimate channel realizations generated by the radio frequency (RF) mirrors, secure mappings between the original information bits and the transmit patterns are designed, where the transmit patterns include the transmit antenna activation pattern (AAP), mirror activation pattern (MAP) and symbol modulation pattern. The secure mappings used by the transmitter change for each transmission and are unavailable at the eavesdropper due to the independent fading of the legitimate link and the eavesdropping link. Based on the secure mappings, the proposed SQCM conveys the source information bits securely through the complex modulation symbol and instantaneous channel realizations by using a single RF chain. The ergodic secrecy rate is analyzed and a closed-form approximation is derived. Simulation results show that the closed-form approximation coincides with the experimental ergodic secrecy rate, and the achievable ergodic secrecy rate is not influenced by the number of eavesdropping antennas or the channel advantage of the eavesdropping link. Compared to the secure MBM scheme using the traditional artificial noise (AN) technique, the proposed SQCM scheme shows significant performance gain without consuming jamming power when the eavesdropper has more antennas than the legitimate receiver. Compared to the precoded MBM and probabilistic optimized MBM schemes exploiting the eavesdropper's CSI, the proposed SQCM scheme has better secrecy performance in all SNR region and medium-to-high SNR regions respectively without requiring the eavesdropper's CSI.
Abstract In this article, we propose a random quadrature spatial modulation (RQSM) scheme to achieve secure transmission in multiple‐input multiple‐output multiantenna eavesdropper channels. We consider the case in which the eavesdropper has more antennas than that of the legitimate receiver, leading to a strong wiretap channel. In this case, the conventional secure quadrature spatial modulation schemes based on the artificially interfering signals are vulnerable to eavesdropping. On the contrary, the proposed RQSM scheme is able to achieve the physical‐layer security without transmitting artificial noises. Specifically, the bits‐to‐symbol mapping of the proposed RQSM is randomized according to the instantaneous channel state information of the legitimate link. Since in a rich scattering environment, the legitimate and the wiretap channels are generally independent of each other due to the spatial decorrelation property. Thus, the eavesdropper can be considered ignorant of the legitimate channel and cannot decode the confidential messages correctly. We derive the ergodic secrecy rate of the proposed RQSM scheme and show that the secrecy performance does not degrade as the number of antennas at the eavesdropper increases, which also outperforms the conventional jamming strategies. In addition, the bit error rate of the RQSM is also analyzed, which shows that security is achieved without sacrificing the system's reliability. Numerical results validate the theoretical derivations and demonstrate the effectiveness of the proposed RQSM scheme.
Existing secure strategies based on precoding-aided spatial modulation (PSM) ensure the secrecy communication by introducing time-varying interference with extra power towards the eavesdropper, which, however, reduces the energy efficiency. In this paper, we propose two novel schemes to enhance the secrecy performance based on PSM. The first scheme utilizes the random antenna selection (RAS) technique, namely RAS- PSM, to generate zero-forcing (ZF) precoding matrices with randomly activated transmit antennas. It ensures efficient transmission to the legitimate user, while confusing the eavesdropper via the turbulence of RAS without extra power consumption. The second scheme, called hybrid secret PSM (HS-PSM), is an enhanced version of RAS-PSM by introducing the time-varying artificial noise into RAS-PSM. The resulting secrecy rates by the two proposed schemes are theoretically analyzed and evaluated via Monte Carlo simulations as well, whose results demonstrate that RAS-PSM achieves a higher secrecy rate than the existing schemes and HS- PSM is capable of further improving the secrecy performance especially at high signal-to-noise ratio (SNR).
In this paper, we investigate the secure transmission for differential quadrature spatial modulation (DQSM) with artificial noise (AN) in multiple-input single-output wiretap networks, where a cooperative jammer helps the secure transmission between transceivers in the presence of an eavesdropper. To evaluate the secrecy performance of the DQSM with AN in the considered wiretap networks, assuming Rayleigh fading, we derive exact and asymptotic closed-form expressions for secrecy outage probability and effective secrecy throughput under two practical scenarios, i.e., Scenario I, where the eavesdropper is passive and its channel state information (CSI) is unavailable, and Scenario II, where the eavesdropper is active and its CSI is available. Finally, numerical simulations demonstrate that increasing the transmit power of transmitter or cooperative jammer can improve the secrecy performance, but too large transmit power at the transmitter or cooperative jammer is not helpful. Moreover, increasing the number of antennas at the transmitter or cooperative jammer brings up better secrecy performance.