The Experts below are selected from a list of 8328 Experts worldwide ranked by ideXlab platform
Naofal Aldhahir - One of the best experts on this subject based on the ideXlab platform.
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secure space time block coding without transmitter csi
IEEE Wireless Communications Letters, 2014Co-Authors: Trevor Allen, Julian Cheng, Naofal AldhahirAbstract:A new technique is presented for securing a space-time block code in the presence of an eavesdropper without channel state information (CSI) at the transmitter. Assuming channel reciprocity between the transmitter and the Intended Receiver, we use the receive signal strength indicator, which is much easier to estimate reliably than CSI, to randomly rotate the information symbols at each transmit antenna without increasing the transmit signal's peak-to-average ratio. It is shown that the proposed scheme guarantees full diversity to an Intended recipient while reducing the diversity order of an eavesdropper to zero even in the presence of perfect channel state information.
Ghadamali Bagherikaram - One of the best experts on this subject based on the ideXlab platform.
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secure joint source channel coding with interference known at the transmitter
Iet Communications, 2012Co-Authors: Ghadamali Bagherikaram, Konstantinos N. PlataniotisAbstract:In this study, the problem of transmitting an independent and identically distributed (i.i.d.) Gaussian source over an i.i.d. Gaussian wire-tap channel, with an i.i.d. Gaussian known interference available at the transmitter is considered. The Intended Receiver is assumed to have a certain minimum signal-to-noise ratio (SNR) and the eavesdropper is assumed to have a strictly lower SNR compared to the Intended Receiver. The objective is to minimise the distortion of source reconstruction at the Intended Receiver. In this study, an achievable distortion is derived when Shannon's source'channel separation coding scheme is used. Three hybrid digital'analogue secure joint source'channel coding schemes are then proposed, which achieve the same distortion. The first coding scheme is based on Costa's dirty-paper-coding scheme and wire-tap channel coding scheme, when the analogue source is not explicitly quantised. The second coding scheme is based on the superposition of the secure digital signal and the hybrid digital'analogue signal. It is shown that for the problem of communicating a Gaussian source over a Gaussian wire-tap channel with side information, there exists an infinite family of secure joint source'channel coding schemes. In the third coding scheme, the quantised signal and the analogue error signal are explicitly superimposed. It is shown that this scheme provides an infinite family of secure joint source'channel coding schemes with a variable number of binning. Finally, the proposed secure hybrid digital'analogue schemes are analysed under the main channel SNR mismatch. It is proven that the proposed schemes can give a graceful degradation of distortion with SNR under SNR mismatch, that is, when the actual SNR is larger than the designed SNR.
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Secure Hybrid Digital-Analog Coding With Side Information at the Receiver
arXiv: Information Theory, 2011Co-Authors: Ghadamali Bagherikaram, Konstantinos N. PlataniotisAbstract:In this work, the problem of transmitting an i.i.d Gaussian source over an i.i.d Gaussian wiretap channel with an i.i.d Gaussian side information available at the Intended Receiver is considered. The Intended Receiver is assumed to have a certain minimum SNR and the eavesdropper is assumed to have a strictly lower SNR, compared to the Intended Receiver. The objective is to minimize the distortion of source reconstruction at the Intended Receiver. In this work, it is shown that the source-channel separation coding scheme is optimum in the sense of achieving minimum distortion. Two hybrid digital-analog Wyner-Ziv coding schemes are then proposed which achieve the minimum distortion. These secure joint source-channel coding schemes are based on the Wyner-Ziv coding scheme and wiretap channel coding scheme when the analog source is not explicitly quantized. The proposed secure hybrid digital-analog schemes are analyzed under the main channel SNR mismatch. It is proven that the proposed schemes can give a graceful degradation of distortion with SNR under SNR mismatch, i.e., when the actual SNR is larger than the designed SNR.
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PIMRC - Secure hybrid digital-analog Wyner-Ziv coding
2011 IEEE 22nd International Symposium on Personal Indoor and Mobile Radio Communications, 2011Co-Authors: Ghadamali Bagherikaram, Konstantinos N. PlataniotisAbstract:In this work, the problem of transmitting an i.i.d Gaussian source over an i.i.d Gaussian wiretap channel with an i.i.d Gaussian side information at the Intended Receiver is considered. The Intended Receiver is assumed to have a certain minimum SNR and the eavesdropper is assumed to have a strictly lower SNR compared to the Intended Receiver. The objective is minimizing the distortion of source reconstruction at the Intended Receiver. In this work, it is shown that the source-channel separation coding scheme is optimum in the sense of achieving the minimum distortion. A hybrid digital-analog Wyner-Ziv coding scheme is then proposed which achieve the minimum distortion. This secure joint source channel coding scheme is based on Wyner-Ziv coding scheme and wiretap channel coding scheme when the analog source is not explicitly quantized. The proposed secure hybrid digital-analog scheme is analyzed under the main channel SNR mismatch. It is proven that the proposed scheme can give a graceful degradation of distortion with SNR under SNR mismatch, i.e., when the actual SNR is larger than the designed SNR.
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Secure Joint Source-Channel Coding With Side Information
arXiv: Information Theory, 2010Co-Authors: Ghadamali Bagherikaram, Konstantinos N. PlataniotisAbstract:In this work, the problem of transmitting an i.i.d Gaussian source over an i.i.d Gaussian wiretap channel with an i.i.d Gaussian side information is considered. The Intended Receiver is assumed to have a certain minimum SNR and the eavesdropper is assumed to have a strictly lower SNR compared to the Intended Receiver. The objective is minimizing the distortion of source reconstruction at the Intended Receiver. In this work, it is shown that unlike the Gaussian wiretap channel without side information, Shannon's source-channel separation coding scheme is not optimum in the sense of achieving the minimum distortion. Three hybrid digital-analog secure joint source channel coding schemes are then proposed which achieve the minimum distortion. The first coding scheme is based on Costa's dirty paper coding scheme and wiretap channel coding scheme when the analog source is not explicitly quantized. The second coding scheme is based on the superposition of the secure digital signal and the hybrid digital-analog signal. It is shown that for the problem of communicating a Gaussian source over a Gaussian wiretap channel with side information, there exists an infinite family of optimum secure joint source-channel coding scheme. In the third coding scheme, the quantized signal and the analog error signal are explicitly superimposed. It is shown that this scheme provides an infinite family of optimum secure joint source-channel channel coding schemes with a variable number of binning. Finally, the proposed secure hybrid digital-analog schemes are analyzed under the main channel SNR mismatch. It is proven that the proposed schemes can give a graceful degradation of distortion with SNR under SNR mismatch, i.e., when the actual SNR is larger than the designed SNR.
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On the secure DoF of the single-antenna MAC
2010 IEEE International Symposium on Information Theory, 2010Co-Authors: Ghadamali Bagherikaram, Abolfazl S. Motahari, Amir K. KhandaniAbstract:A new achievability rate region for the secure discrete memoryless Multiple-Access-Channel (MAC) is presented. Thereafter, a novel secure coding scheme is proposed to achieve a positive Secure Degrees-of-Freedom (S-DoF) in the single-antenna MAC. This scheme converts the single-antenna system into a multiple-dimension system with fractional dimensions. The achievability scheme is based on the alignment of signals into a small sub-space at the eavesdropper, and the simultaneous separation of the signals at the Intended Receiver. Tools from the field of Diophantine Approximation in number theory are used to analyze the probability of error in the coding scheme.
Aylin Yener - One of the best experts on this subject based on the ideXlab platform.
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MIMO wiretap channels with unknown and varying eavesdropper channel states
IEEE Transactions on Information Theory, 2014Co-Authors: Xiang He, Aylin YenerAbstract:In this paper, a class of information theoretic secrecy problems is addressed where the eavesdropper channel state is completely unknown to the legitimate parties. In particular, a Gaussian MIMO wiretap channel is considered, where the eavesdropper channel state can vary from one channel use to the next, and the overall channel state sequence is known only to the eavesdropper. When the eavesdropper has fewer antennas than the transmitter and its Intended Receiver, a positive secrecy rate in the sense of strong secrecy is proved to be achievable and shown to match with the converse in secure degrees of freedom. This yields the conclusion that secure communication is possible regardless of the location or channel states of the eavesdropper. Additionally, it is observed that, the present setting renders the secrecy capacity problems for some multiterminal wiretap-type channels more tractable as compared to the case with full or partial knowledge of eavesdropper channel states. To demonstrate this observation, secure degrees of freedom regions are derived for the Gaussian MIMO multiple access (MAC) wiretap channel and the two-user Gaussian MIMO broadcast (BC) wiretap channel, where the transmitter(s) and Intended Receiver(s) have the same number of antennas.
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Providing Secrecy With Structured Codes: Two-User Gaussian Channels
IEEE Transactions on Information Theory, 2014Co-Authors: Aylin YenerAbstract:Recent results have shown that structured codes can be used to construct good channel codes, source codes, and physical layer network codes for Gaussian channels. For Gaussian channels with secrecy constraints, however, efforts to date rely on Gaussian random codes. In this paper, we advocate that structure in random code generation is useful for providing secrecy as well. In particular, a Gaussian wiretap channel in the presence of a cooperative jammer is studied. Previously, the achievable secrecy rate for this channel was derived using Gaussian signaling, which saturated at high signal-to-noise ratio (SNR), owing to the fact that the cooperative jammer simultaneously helps by interfering with the eavesdropper, and hurts by interfering with the Intended Receiver. In this paper, a new achievable rate is derived through imposing a lattice structure on the signals transmitted by both the source and the cooperative jammer, which are aligned at the eavesdropper but remain separable at the Intended Receiver. We prove that the achieved secrecy rate does not saturate at high SNR for all values of channel gains except when the channel is degraded.
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achievable rates for the general gaussian multiple access wire tap channel with collective secrecy
arXiv: Information Theory, 2006Co-Authors: Ender Tekin, Aylin YenerAbstract:We consider the General Gaussian Multiple Access Wire-Tap Channel (GGMAC-WT). In this scenario, multiple users communicate with an Intended Receiver in the presence of an intelligent and informed eavesdropper who is as capable as the Intended Receiver, but has different channel parameters. We aim to provide perfect secrecy for the transmitters in this multi-access environment. Using Gaussian codebooks, an achievable secrecy region is determined and the power allocation that maximizes the achievable sum-rate is found. Numerical results showing the new rate region are presented. It is shown that the multiple-access nature of the channel may be utilized to allow users with zero single-user secrecy capacity to be able to transmit in perfect secrecy. In addition, a new collaborative scheme is shown that may increase the achievable sum-rate. In this scheme, a user who would not transmit to maximize the sum rate can help another user who (i) has positive secrecy capacity to increase its rate, or (ii) has zero secrecy capacity to achieve a positive secrecy capacity.
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on secure signaling for the gaussian multiple access wire tap channel
Asilomar Conference on Signals Systems and Computers, 2005Co-Authors: Ender Tekin, Semih Serbetli, Aylin YenerAbstract:We consider the Gaussian Multiple Access WireTap Channel (GMAC-WT) where multiple users communicate with the Intended Receiver in the presence of an intelligent and informed wire-tapper (eavesdropper). The wire-tapper receives a degraded version of the signal at the Receiver. We assume that the wire-tapper is as capable as the Intended Receiver, and there is no other shared secret key. We consider two different secure communication scenarios: (i) keeping the wire-tapper totally ignorant of the message of any group of users even if the remaining users are compromised, (ii) using the secrecy of the other users to ensure secrecy for a group of users. We first derive the outer bounds for the secure rate region. Next, using Gaussian codebooks, we show the achievability of a secure rate region for each measure in which the wire-tapper is kept perfectly ignorant of the messages. We also find the power allocations that yield the maximum sum rate, and show that upper bound on the secure sum rate can be achieved by a TDMA scheme. We present numerical results showing the new rate region and compare it with that of the Gaussian Multiple-Access Channel (GMAC) with no secrecy constraints.
Trevor Allen - One of the best experts on this subject based on the ideXlab platform.
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secure space time block coding without transmitter csi
IEEE Wireless Communications Letters, 2014Co-Authors: Trevor Allen, Julian Cheng, Naofal AldhahirAbstract:A new technique is presented for securing a space-time block code in the presence of an eavesdropper without channel state information (CSI) at the transmitter. Assuming channel reciprocity between the transmitter and the Intended Receiver, we use the receive signal strength indicator, which is much easier to estimate reliably than CSI, to randomly rotate the information symbols at each transmit antenna without increasing the transmit signal's peak-to-average ratio. It is shown that the proposed scheme guarantees full diversity to an Intended recipient while reducing the diversity order of an eavesdropper to zero even in the presence of perfect channel state information.
A. Lee Swindlehurst - One of the best experts on this subject based on the ideXlab platform.
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ACSSC - On the optimality of polar codes for the deterministic wiretap channel
2013 Asilomar Conference on Signals Systems and Computers, 2013Co-Authors: S. Ali A. Fakoorian, A. Lee SwindlehurstAbstract:The wiretap channel introduced by Wyner [1] in 1975 consists of a transmitter with a confidential message for an Intended Receiver that needs to be kept secret from an eavesdropper. The secrecy capacity of the wiretap channel quantifies the maximum rate at which a transmitter can reliably send a secret message to its Intended recipient without it being decoded by an eavesdropper. While the secrecy capacity is achievable based upon a random-coding argument, constructing channel coding schemes that achieve the secrecy capacity for a general wiretap channel is still an open problem. In this paper, we show that polar coding is an optimal coding scheme in achieving the secrecy capacity for the deterministic wiretap channel, where the channel between the transmitter and the Intended Receiver and the channel between the transmitter and the eavesdropper are arbitrary and deterministic.
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ACSCC - QoS-constrained robust beamforming in MISO wiretap channels with a helper
2011 Conference Record of the Forty Fifth Asilomar Conference on Signals Systems and Computers (ASILOMAR), 2011Co-Authors: Jing Huang, A. Lee SwindlehurstAbstract:In this paper, we develop robust beamforming strategies for multiple-input single-output (MISO) wiretap channels with a helper. The channel state information (CSI) for the legitimate link is assumed to be available while the CSI for the eavesdropper's channel is imperfect, and is assumed to be norm-bounded by some known constant. We optimize the worst-case performance for the following problems: 1) minimizing the signal to interference-plus-noise ratio (SINR) at the eavesdropper while maintaining an SINR constraint at the Intended Receiver, 2) maximizing the SINR at the Intended Receiver while forcing an SINR constraint at the eavesdropper, and 3) minimizing the global transmit power while satisfying SINR constraints at both the legitimate user and the eavesdropper. Simulation examples show the advantages of the robust designs over the non-robust counterparts.
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solutions for the mimo gaussian wiretap channel with a cooperative jammer
IEEE Transactions on Signal Processing, 2011Co-Authors: S. Ali A. Fakoorian, A. Lee SwindlehurstAbstract:We study the Gaussian MIMO wiretap channel with a transmitter, a legitimate Receiver, an eavesdropper and an external helper, each equipped with multiple antennas. The transmitter sends confidential messages to its Intended Receiver, while the helper transmits jamming signals independent of the source message to confuse the eavesdropper. The jamming signal is assumed to be treated as noise at both the Intended Receiver and the eavesdropper. We obtain a closed-form expression for the structure of the artificial noise covariance matrix that guarantees a secrecy rate larger or at least equal to the secrecy capacity of the wiretap channel with no jamming signal. We also describe how to find specific realizations of this covariance matrix expression that provide good secrecy rate performance, even when there is no nontrivial null space between the helper and the Intended Receiver. Unlike prior work, our approach considers the general MIMO case, and is not restricted to SISO or MISO scenarios.
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Secrecy capacity of MISO Gaussian wiretap channel with a cooperative jammer
2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications, 2011Co-Authors: S. Ali A. Fakoorian, A. Lee SwindlehurstAbstract:We study the Gaussian MISO wiretap channel with a transmitter, a legitimate Receiver, an eavesdropper and an external helper, where the transmitter and the helper have an arbitrary number of antennas but the Intended Receiver and the eavesdropper have only one antenna. The transmitter sends confidential messages to its Intended Receiver, while the helper transmits jamming signals independent of the source message to confuse the eavesdropper. The jamming signal is assumed to be treated as noise at both the Intended Receiver and the eavesdropper. Assuming Gaussian signaling at the helper, we obtain the optimal beamformers at the transmitter and the helper that achieve the secrecy capacity.
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ACSCC - Secure space-time block coding via artificial noise alignment
2011 Conference Record of the Forty Fifth Asilomar Conference on Signals Systems and Computers (ASILOMAR), 2011Co-Authors: S. Ali A. Fakoorian, Hamid Jafarkhani, A. Lee SwindlehurstAbstract:(STBC) for MIMO Gaussian wiretap channels. It is assumed that the transmitter has the Receiver's channel state information, but not that of the eavesdropper. We first propose a full-rate STBC that provides separate decoding complexity (rather than pairwise) at the Intended Receiver, while requiring an exhaustive search for Maximum Likelihood (ML) decoding at the eavesdropper. Next we make the code more secure by including artificial noise symbols which (for the asymptotically high SNR regime) are aligned with each other and subtracted from the information symbols at the Intended Receiver, but which can not be cancelled at the eavesdropper. Simulations demonstrate the enhanced physical-layer security that results.