We investigate the secrecy performance of a codebook based transmission beamforming for a sensitive data link against passive eavesdropping. We characterize the secrecy outage probability of a communication link that is being eavesdropped. We consider a limited feedback scenario where the transmitter is using a predefined codebook known to both transmitter and receiver for beamforming, and analyze the secrecy outage probability of the link when it being eavesdropped. Our analysis also provides the secrecy outage probability of the beamforming transmission in the direction of the intended receiver. We characterize how the secrecy outage probability improves as the number of transmit antennas increases. We further analyze the effect of codebook design on secrecy enhancement and provide bounds on the secrecy outage probability of codebook beamforming.
We investigate the secrecy performance of a codebook based transmission beamforming for a sensitive data link against passive eavesdropping. We characterize the secrecy outage probability of a communication link that is being eavesdropped. We consider a limited feedback scenario where the transmitter is using a predefined codebook known to both transmitter and receiver for beamforming, and analyze the secrecy outage probability of the link when it being eavesdropped. Our analysis also provides the secrecy outage probability of the beamforming transmission in the direction of the intended receiver. We characterize how the secrecy outage probability improves as the number of transmit antennas increases. We further analyze the effect of codebook design on secrecy enhancement and provide bounds on the secrecy outage probability of codebook beamforming.
In this paper we study about the secure communication among wireless shared medium using secrecy performance of a codebook based transmission beamforming with limited feedback. And avoid attacker from stealing the confidential data. In the feedback method transmitter is using a predefined codebook known to transmitter and receiver knows it after producing index value as feedback during beamforming. The secrecy outage probability is analyzed to find whether it is stealed. The bound values are provided on the secrecy outage probability. The fading in multiple antenna (MIMO) wire-tap channel is investigated under short term power constraints. The secret diversity multiplexing tradeoff (DMT) is found for no transmitter side channel state information (CSI) and for full CSI. When there is no CSI at the transmitter, while using Gaussian codebooks, it seems that both transmitter and receiver antennas are stealed, and the secret DMT depends on the other degrees of freedom. When CSI is available at the transmitter (CSIT), then transmitter antenna is only stealed.
We study secure multi-antenna transmission with limited feedback from the intended receiver and no feedback from the malicious eavesdropper. Our system uses the artificial-noise-aided beamforming approach to enhance secrecy, considering slow fading channels with outage constraints on the reliability performance of legitimate communication and the secrecy performance against eavesdropping. Our analytical results provide conditions on the minimum number of feedback bits and the minimum strength of the intended channel for making secure transmission possible. We observe that strengthening the secrecy outage constraint puts higher requirements on the number of feedback bits and the strength of the intended channel. To maximize the achievable secrecy rate, the optimal transmit power allocation between the information signal and the artificial noise is also derived in closed form.
We consider the secure beamforming transmission over a quasi-static block fading channel from a multi-antenna transmitter to a desired single-antenna receiver, in the presence of a passive single-antenna eavesdropper. We focus on a practical scenario where the transmitter can only acquire the statistical channel knowledge of the eavesdropper and the partial channel knowledge of the legitimate receiver through a finite amount of signaling overhead. To keep control of the outage events caused by the limited channel knowledge, We firstly propose a strategy to determine the wiretap code parameters under the outage constraints, based on which we establish a necessary transmission condition to guarantee a positive secrecy rate. Aided by this transmission condition, we propose an on-off-based transmission scheme and characterize the secrecy throughput performance of the system. Our designed transmission scheme is beneficial for the deployment of physical layer security in practical frequency division duplex (FDD) systems with limited training and feedback.
Exploiting the randomness embedded in wireless channels, the physical-layer security techniques can provide additional security robustness against malicious eavesdropping at the physical layer of communication systems. To further this line of study, this thesis focuses on developing advanced multi-antenna transmission strategies for enhancing the secrecy performance of wireless communication systems. Assuming perfect channel feedback from the desired receiver and none from the eavesdropper, we consider beamforming with smartly injected artificial noise, aiming to confuse the eavesdropper whilst leaving the desired receiver unaffected. The system parameters are either chosen to be fixed for all transmissions, or adaptively adjusted based on the channel feedback from the desired receiver. For both cases, we provide novel and explicit design solutions for achieving the maximum throughput subject to a secrecy outage constraint. We then derive accurate approximations for the maximum throughput, and give new insights into the additional power cost for achieving a higher security level and the throughput gain of adaptive transmission over non-adaptive transmission. Having investigated the perfect feedback scenario, we then relax the feedback assumption and consider practical effects imposed by limited feedback constraints on the channel from the desired receiver to the transmitter. To deal with quantization error due to limited feedback whilst also accounting for unknown channel of the eavesdropper, we specify a connection outage constraint to guarantee the reliability of desired communication and a secrecy outage constraint to guard against malicious eavesdropping. Under dual outage constraints, we derive a novel optimized rate-adaptive transmission design to maximize the average secrecy throughput. New insights regarding the optimal power/feedback allocation and the number of feedback bits required for efficient quantization are obtained through our analysis. Our preceding study focused on isolated point-to-point transmission without any interference. However, the performance of contemporary wireless networks is often limited by interference from concurrent transmissions. To characterize the impact of interference on secure communication, we consider an interference-limited large-scale network. To confuse the malicious eavesdroppers, in addition to information-bearing signals, the transmitters are designed to generate artificial noise through either beamforming or antenna sectoring in a distributed manner. For both cases, using tools from stochastic geometry, we provide a statistical characterization of the reliability performance of desired communication and the secrecy performance against eavesdropping. We then investigate the networkwide secrecy throughput performance and optimize the transmit power allocation. Our analysis reveals interesting differences between the beamforming and sectoring approaches in terms of the optimal power allocation and the maximum networkwide secrecy throughput.
In this paper, we investigate the ergodic secrecy capacity of a block-fading wiretap channel with limited channel knowledge at the transmitter. We consider that the legitimate receiver, the eavesdropper, and the transmitter are equipped with multiple antennas and that the receiving nodes are aware of their respective channel matrices. On the other hand, the transmitter is only provided by a B-bit feedback of the main channel state information. The feedback bits are sent by the legitimate receiver, at the beginning of each fading block, over an error-free public link with limited capacity. The statistics of the main and the eavesdropper channel state information are known at all nodes. Assuming an average transmit power constraint, we establish upper and lower bounds on the ergodic secrecy capacity. Then, we present a framework to design the optimal codebooks for feedback and transmission. In addition, we show that the proposed lower and upper bounds coincide asymptotically, as the capacity of the feedback link becomes large, i.e., B→∞, hence fully characterizing the ergodic secrecy capacity in this case. Besides, we analyze the asymptotic behavior of the presented secrecy rates, at high signal-to-noise ratio, and evaluate the gap between the bounds.
We study the ergodic secrecy capacity of a block- fading wiretap channel when there are multiple antennas at the transmitter, the legitimate receiver and the eavesdropper. We consider that the receivers are aware of their respective channel matrices while the transmitter is only provided by a B-bits feedback of the main channel state information. The feedback bits are sent by the legitimate receiver, at the beginning of each fading block, over an error free public link with limited capacity. Assuming an average transmit power constraint, we provide an upper and a lower bounds on the ergodic secrecy capacity. Then, we present a framework to design the optimal codebooks for feedback and transmission. In addition, we show that the proposed lower and upper bounds coincide asymptotically as the capacity of the feedback link becomes large; hence, fully characterizing the secrecy capacity in this case.