With the aid of spatial modulation (SM), the concept of spatial and direction modulation (SDM) has been developed to enhance the physical security even if the eavesdropper shares the same direction with the legitimate receiver. However, the above advantage may no longer hold when the eavesdropper is also equipped with distributed receivers. For alleviating this problem, following the recently presented idea of covert information mapping (CIM) [1], we extend the original system in order to construct a robust structure as CIM-SDM. Simulation results demonstrate that the proposed CIM-SDM system can remain the security of information transmission in the context of distributed receivers at Bob, at the cost of moderate performance loss at the legitimate user.
With the aid of spatial modulation (SM), the concept of spatial and direction modulation (SDM) has been developed to enhance the physical security even if the eavesdropper shares the same direction with the legitimate receiver. However, the above advantage may no longer hold when the eavesdropper is also equipped with distributed receivers. For alleviating this problem, following the recently presented idea of covert information mapping (CIM) [1], we extend the original system in order to construct a robust structure as CIM-SDM. Simulation results demonstrate that the proposed CIM-SDM system can remain the security of information transmission in the context of distributed receivers at Bob, at the cost of moderate performance loss at the legitimate user.
Recently, the concept of spatial and direction modulation (SDM) has been developed to reap the advantages of both spatial modulation (SM) and directional modulation (DM). On the one hand, DM ensures the transmission security at the expected direction. On the other hand, the structure of SM-aided distributed receivers can enhance the security even if the eavesdropper is located in the same direction as the legitimate receiver. However, the above advantages are achieved based on the assumption that the eavesdropper is not equipped with distributed receivers. On the other hand, the information security can no longer be guaranteed when the eavesdropper is also equipped with distributed receivers. To alleviate this problem, we considered a joint design of SDM and covert information mapping (CIM) in order to conceive of a more robust structure of CIM-SDM. Furthermore, both the detection performances at the eavesdropper and the legitimate user were quantified through theoretical derivation. In general, both the analysis and simulation results supported that the proposed CIM-SDM structure provides more robust secure performance compared to the original SDM, even if the extreme condition of distributed receivers at the eavesdropper is considered, at the cost of moderate performance loss at the legitimate user.
In this paper, a novel transmission strategy, referred to as mapping-varied spatial modulation, is proposed for physical layer security, where the transmitter varies mapping patterns for the radiated information and the antenna information of spatial modulation, based on the instantaneous pattern of legitimate channel quality information that is unknown to eavesdroppers. Therefore, eavesdroppers cannot successfully decode the confidential information and the transmission over the legitimate link is secured from the wire-tap of eavesdroppers, without relying on higher-layer encryption. An important virtue of the proposed transmission strategy is that the transmitter does not need to know eavesdroppers' channels states at all. To further demonstrate the advantage of this scheme, its secrecy rate was formulated for the purpose of facilitating the performance evaluation. Moreover, illustrative numerical results pertaining to the metrics of ergodic secrecy rate and secrecy outage probability not only substantiate the validity of the proposed transmission strategy, but also provide useful references for the system design with the mapping-varied spatial modulation, from the view of physical layer security.
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.
Addressing the problem of wireless physical layer security transmission for finite alphabet input systems,a spatial modulation secure transmission method is proposed.On the basis of information theory,the method utilizes the receive antenna indices of multiple-input multiple-output (MIMO) system to bear information,and randomizes the eavesdropper’s equivalent channel by switching the receive antennas,which can guarantee physical layer security transmission.First,the different receiving performances of the legitimate user and eavesdropper are analyzed in the spatial modulation secure transmission system.Second,the mutual information and secrecy mutual information of the transmission system are calculated,and two sufficient conditions that ensure positive secrecy mutual information are pointed out.Finally,an estimation algorithm of mutual information is provided.Moreover,the symmetry of finite alphabet set is exploited to decrease the computational complexity.Theoretical analysis and numerical simulation results verify the availability of the security transmission method.
Directional modulation (DM) refers to a class of efficient techniques for enhancing the physical layer security of wireless communications. However, conventional DM approaches cannot guarantee the transmission security when eavesdroppers are located close to the legitimate user. In this paper, to mitigate this problem, a new DM scheme with cooperative receivers (DM-CR) is proposed for secrecy communications. Specifically, the legitimate user employs multiple cooperative receivers, and a predefined distortion factor set is introduced to the beamforming vector. The proposed DM-CR scheme is able to guarantee transmission security regardless of the direction or location of the eavesdroppers. Furthermore, the average bit error probability of the proposed DM-CR scheme is investigated. Both analytical and simulation results are presented to show that the proposed DM-CR scheme significantly outperforms the benchmark in terms of the bit error rate, so as to provide secure transmission toward future wireless communications.
In the conventional directional modulation (DM) system without relay aiding, when the eavesdropper locates within the main-beam of the desired direction, it can intercept the confidential message from source Alice. In this paper, we propose a strategy to enhance physical-layer security of direction modulation in wireless transmission with the help of multi-relay cooperation. In this scenario, the confidential messages are forwarded to the desired destination receiver, and the artificial noise (AN) is enforced to the eavesdroppers with the aid of multi-relays and direction modulation such that the eavesdropper can not successfully recover the useful information from its received signals. The simulation results show that the proposed method achieves a significantly higher signal-to-interference-plus-noise ratio (SINR) peak at the destination position than at other positions outside the main-beam of the desired position and its secrecy rate performance at undesired position is so poor that the secure transmission is guaranteed.