In this paper, we present and analyze utilizing generalized selection combining (GSC) scheme to enhance the physical layer (PHY) security of a wireless communication system consisting of a single antenna transmitter, a multi-antennas receiver and a multi-antennas eavesdropper. We consider a practical scenario where GSC scheme is applied to the receiver considering both the complexity and the energy dissipation while maximal ratio combining (MRC) scheme is applied to the eavesdropper in order to maximize its instantaneous signal to noise ratio (SNR). This work bridges the gap between the existing works utilizing MRC scheme and transmit antenna selection (TAS) scheme to enhance the PHY security. Closed-form expressions for both the probability of non-zero secrecy capacity and the exact secrecy outage probability are derived over Rayleigh fading channels. The security capacity performances are also shown and analyzed through numerical results. The impacts of the number of selected branches, the average SNR of transmitter's channel and eavesdropper's channel are discussed.
In this paper, we present and analyze utilizing generalized selection combining (GSC) scheme to enhance the physical layer (PHY) security of a wireless communication system consisting of a single antenna transmitter, a multi-antennas receiver and a multi-antennas eavesdropper. We consider a practical scenario where GSC scheme is applied to the receiver considering both the complexity and the energy dissipation while maximal ratio combining (MRC) scheme is applied to the eavesdropper in order to maximize its instantaneous signal to noise ratio (SNR). This work bridges the gap between the existing works utilizing MRC scheme and transmit antenna selection (TAS) scheme to enhance the PHY security. Closed-form expressions for both the probability of non-zero secrecy capacity and the exact secrecy outage probability are derived over Rayleigh fading channels. The security capacity performances are also shown and analyzed through numerical results. The impacts of the number of selected branches, the average SNR of transmitter's channel and eavesdropper's channel are discussed.
We propose and analyze transmit antenna selection (TAS) to enhance physical layer security in a wiretap channel with multiple antennas at the transmitter, the receiver, and the eavesdropper. We consider the practical scenario of passive eavesdropping, where the transmitter does not have any channel state information (CSI) of the eavesdropper's channel. In the main channel between the transmitter and the receiver, we select a single antenna at the transmitter that maximizes the instantaneous signal-to-noise ratio (SNR) at the receiver. At the receiver and the eavesdropper, we consider two combining techniques: 1) maximal-ratio combining (MRC) and 2) selection combining (SC). For non-identical Rayleigh fading between the main channel and the eavesdropper's channel, we first derive new closed-form expressions for the exact and asymptotic secrecy outage probabilities. The asymptotic results accurately reveal the secrecy diversity order and the secrecy array gain. Next, we derive new closed-form expressions for the probability of positive secrecy and characterize the ε-outage secrecy capacity. We show that, under TAS/MRC and TAS/SC protocols, the secrecy outage probability approaches zero and the ε-outage secrecy capacity increases with increasing number of transmitter antennas.
We introduce an opportunistic scheduling to enhance the physical layer security with transmit antenna selection (TAS) in multiuser environment. We consider a wireless communication system composed of a single transmitter and multiple legitimate users in the presence of several eavesdroppers with each node having multiple antennas under quasi-static Rayleigh fading channel. The transmitter selects the best transmitting antenna and the best user to maximize signal-to-noise ratio (SNR) at the selected user. The user and eavesdropper can employ either selection combining (SC) or maximal ratio combining (MRC) to combine the received signals. New closed-form expressions for probability of positive secrecy and outage are derived. Moreover, asymptotic analysis reveals the outage diversity gain and array gain for the proposed scheme. The impact of number of users, eavesdroppers, and antennas on secrecy performance are clearly demonstrated with mathematical analysis and numerical results.
We propose and analyze transmit antenna selection (TAS) to enhance physical layer security in a wiretap channel with NAantennas at the transmitter, NBantennas at the receiver, and NEantennas at the eavesdropper. We focus on the practical scenario where the transmitter does not have any channel state information (CSI) of the eavesdropper's channel. The transmitter selects a single antenna that maximizes the instantaneous signal-to-noise ratio (SNR) at the receiver. The receiver and the eavesdropper employ either maximal-ratio combining (MRC) or selection combining (SC) to combine the received signals. For the proposed protocols, we derive new closed-form expressions for the probability of non-zero secrecy capacity. We consider Nakagami-m fading with non-identical fading parameters of the main channel, mB, and of the eavesdropper's channel, mE. Next, we derive new closed-form expressions for the exact secrecy outage probability, based on which the ε-outage secrecy capacity is characterized. Based on the exact expressions, we derive the asymptotic secrecy outage probability which accurately reveals the secrecy diversity order and the secrecy array gain. We confirm that the proposed protocols achieve identical secrecy diversity orders of NANBmB. An interesting conclusion is reached that this diversity order is independent of NEand mE. Furthermore, we prove that under the proposed protocols, the secrecy outage probability and the ε-outage secrecy capacity improve with increasing NA.
The impact of both maximal ratio combining (MRC) and relay selection on the physical layer security in wireless communication systems is studied by analyzing some important factors, including the probability characteristic of the legitimate receiver (Bob) and malicious eavesdropper (Eve)'s end-to-end signal-to-noise ratio (SNR), the secrecy outage probability, and the average secrecy channel capacity over Rayleigh fading Channel. We assume that Bob receives its data from both the relay and the source by cooperative communication, provided that MRC is employed at the receiver. Compared to the conventional MRC methods, a higher spatial diversity order can be exploited by performing relay selection in the proposed method, as validated via both theoretical analysis and numerical simulation. The theoretical closed-form expressions for some figures of merit, e.g., the secrecy outage probability and the average secrecy capacity, are all consistent with the numerical results.
In order to evaluate the physical layer security performance of Transmit Antenna Selection with channel Prediction(TASP)/receive Maximum Ratio Combining(MRC) wireless communication system over Rayleigh block fading channel in multi-eavesdropper scene,the exact analytic expressions for the non-zero security capacity probability,security outage probability and asymptotic security outage probability of TASP/MRC wireless communication systems based on Minimum Mean Square Error(MMSE) channel predictor are derived.On this basis,the impacts of the parameters such as the number of eavesdroppers,normalized feedback delay,the number of transmit/receive antennas on the physical layer security performance of system are analyzed.Numerical calculation and simulation results show that,in a TASP/MRC system,reducing the normalized delay and the number of eavesdroppers or increasing the number of legitimate receive antennas can improve the physical layer security performance.In the case of high Signal Noise Ratio(SNR),the physical layer security diversity gain is equal to the number of legitimate receive antennas,but has nothing to do with the number of eavesdropper and transmit/receive antennas.
We investigate the physical layer security for opportunistic scheduling scheme using transmit antenna selection (TAS) with maximal ratio combining (MRC) at receiver and eavesdropper under a quasi-static Rayleigh fading channel. We assume a scenario composed of a single transmitter, multiple users and a single eavesdropper each equipped with multiple antennas. The transmitter selects best transmit antenna and best user to enhance the secure communication. A theoretical analysis is performed to derive new closed form expressions for probability of positive secrecy and outage probability at a normalized secrecy rate. Furthermore, asymptotic analysis on the outage probability reveals the outage diversity gain and array gain. It is confirmed that number of antennas at eavesdropper impacts on secrecy array gain while the outage diversity gain is determined by the product of number of users and antennas at the transmitter and the user. From numerical results, TAS is verified as a suitable option for secure opportunistic scheduling.