24 results on '"Kuhestani, Ali"'
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2. A machine learning multi-hop physical layer authentication with hardware impairments
- Author
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Ezzati Khatab, Zahra, Mohammadi, Abbas, Pourahmadi, Vahid, and Kuhestani, Ali
- Published
- 2024
- Full Text
- View/download PDF
3. A new practical physical layer secret key generation in the presence of an untrusted relay
- Author
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Keshavarzi, Mohammadreza, Zayyani, Hadi, Kuhestani, Ali, and Ahmadi, Hossein
- Published
- 2024
- Full Text
- View/download PDF
4. Can a multi-hop link relying on untrusted amplify-and-forward relays render security?
- Author
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Mamaghani, Milad Tatar, Kuhestani, Ali, and Behroozi, Hamid
- Published
- 2021
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- View/download PDF
5. Characterization of untrusted relaying networks in the presence of an adversary jammer
- Author
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Saedi, Hamed, Mohammadi, Abbas, and Kuhestani, Ali
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- 2020
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6. Intelligent Reflecting Surface Assisted Secret Key Generation Under Spatially Correlated Channels in Quasi-Static Environments
- Author
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Shahiri, Vahid, Behroozi, Hamid, and Kuhestani, Ali
- Subjects
Signal Processing (eess.SP) ,FOS: Electrical engineering, electronic engineering, information engineering ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Physical layer key generation (PLKG) can significantly enhance the security of classic encryption schemes by enabling them to change their secret keys significantly faster and more efficient. However, due to the reliance of PLKG techniques on channel medium, reaching a high secret key rate is challenging in static environments. Recently, exploiting intelligent reflecting surface (IRS) as a means to induce randomness in static wireless channels has received significant research interest. However, the impact of spatial correlation between the IRS elements is rarely studied. To be specific, for the first time, in this contribution, we take into account a spatially correlated IRS which intends to enhance the secret key generation (SKG) rate in a static medium. Closed form analytical expressions for SKG rate are derived for the two cases of random phase shift and equal random phase shift for all the IRS elements. We also analyze the temporal correlation between the channel samples to ensure the randomness of the generated secret key sequence. We further formulate an optimization problem in which we determine the optimal portion of time within a coherence interval dedicated for the direct and indirect channel estimation. We show the accuracy and the fast convergence of our proposed sequential convex programming (SCP) based algorithm and discuss the various parameters affecting spatially correlated IRS assisted PLKG.
- Published
- 2022
7. Joint Information Theoretic Secrecy and Covert Communication in the Presence of an Untrusted User and Warden
- Author
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Forouzesh, Moslem, Azmi, Paeiz, Kuhestani, Ali, and Yeoh, Phee Lep
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Signal Processing (eess.SP) ,FOS: Electrical engineering, electronic engineering, information engineering ,Data_CODINGANDINFORMATIONTHEORY ,Electrical Engineering and Systems Science - Signal Processing - Abstract
In this paper, we investigate joint information theoretic secrecy and covert communication in a single-input multi-output (SIMO) system where a transmitter (Alice) is communicating with two legitimate users (Bob and Carol). We consider that an untrusted user and a warden node are also present in the network attempting to attack the secure and covert communications to Bob and Carol, respectively. Specifically, Bob requires secure communications such that his messages from Alice are not decoded by the untrusted user, while Carol requires covert communications such that her messages from Alice are not detected by the warden. To do so, we consider that Alice transmits Carol's messages during selected time slots to hide them from the warden while also transmitting Bob's messages in each time slot contentiously. We formulate an optimization problem with the aim of maximizing the average rate subject to a covert communication requirement and a secure communications constraint. Since the proposed optimization problem is non-convex, we utilize successive convex approximation to obtain a tractable solution. We consider practical assumptions that Alice has imperfect knowledge of the warden's location and imperfect channel state information (CSI) of Bob and Carol. Our numerical examples highlight that the imperfect CSI at Carol has a more detrimental impact on the average rate compared to imperfect CSI at Bob., 9 pages, 5 figures, 1 table
- Published
- 2020
8. On the Physical Layer Security of Untrusted Millimeter Wave Relaying Networks: A Stochastic Geometry Approach.
- Author
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Ragheb, Mohammad, Hemami, S. Mostafa Safavi, Kuhestani, Ali, Ng, Derrick Wing Kwan, and Hanzo, Lajos
- Abstract
The physical layer security (PLS) of millimeter wave (mmWave) communication systems is investigated, where the secure source-to-destination communication is assisted by an untrusted relay selected from a group of them and there are also several passive eavesdroppers (Eves) in the network. In the considered system model, while the distributions of the untrusted relays and Eves follow a homogeneous Poisson Point Process (PPP). To maximize the instantaneous secrecy rate, a novel joint relay selection and power allocation (JRP) method is developed where the destination and source aim for jamming the reception of both the untrusted relays and passive Eves. New expressions of the optimal power allocation (OPA) are derived for both non-colluding Eves (NCE) and colluding Eves (CE). Subsequently, by considering the impact of potential blockages, new closed-form equations are derived for analyzing the system’s ergodic secrecy rate (ESR) and secrecy outage probability (SOP) for transmission over fading mmWave channels. Finally, numerical examples are provided for demonstrating the superiority of our proposed JRP method over the relevant benchmarks found in the literature. Interestingly, the ESR increases with the density of untrusted relays for both the NCE and CE scenarios, which is a benefit of the improved probability of selecting a relay with a stronger second-hop channel. Furthermore, in the low transmit power regime, employing relatively low mmWave frequencies achieves better ESR, while in the high transmit power regime, high mmWave frequencies provide higher ESR. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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9. Covert Transmission with Antenna Selection and Using an External Jammer
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Sarkheil, Morteza, Azmi, Paeiz, Forouzesh, Moslem, and Kuhestani, Ali
- Subjects
Signal Processing (eess.SP) ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,FOS: Electrical engineering, electronic engineering, information engineering ,Data_CODINGANDINFORMATIONTHEORY ,Electrical Engineering and Systems Science - Signal Processing - Abstract
This paper adopts the antenna selection technique to enhance the covert rate in a wireless communication network comprised of a source, a destination , an external jammer and an eavesdropper. In the covert communication, the level of transmit power is low and hence a source with multiple antennas can be adopted to send the information toward the single antenna destination while concurrently, the jammer transmits an artificial noise signal. For this system model, we consider a scenario where the source is forced to select one or several of its antennas to transmit its confidential information due to its limited RF chains. Furthermore, we consider two different jamming scenarios to support our covert communication: 1) The destination is unable to cancel the jamming signal, 2) The destination can subtract the jamming signal. For such a communication network, our aim is to maximize the covert rate subject to power constraint and covert communication requirement. In the first scenario, the optimization problem is non-convex, and hence, it can be solved through using Difference of Convex function (DC) method while the optimization problem of the second scenario is intrinsically convex. Our numerical results show that the higher the number of selected antennas at the transmitter, the higher the covert rate will be achieved.
- Published
- 2018
10. Optimal Power Allocation by Imperfect Hardware Analysis in Untrusted Relaying Networks
- Author
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Kuhestani, Ali, Mohammadi, Abbas, Wong, Kai-Kit, Yeoh, Phee Lep, Moradikia, Majid, and Khandaker, Muhammad Ruhul Amin
- Subjects
FOS: Computer and information sciences ,Computer Science - Cryptography and Security ,Information Theory (cs.IT) ,Computer Science - Information Theory ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Data_CODINGANDINFORMATIONTHEORY ,Cryptography and Security (cs.CR) - Abstract
By taking a variety of realistic hardware imperfections into consideration, we propose an optimal power allocation (OPA) strategy to maximize the instantaneous secrecy rate of a cooperative wireless network comprised of a source, a destination and an untrusted amplify-and-forward (AF) relay. We assume that either the source or the destination is equipped with a large-scale multiple antennas (LSMA) system, while the rest are equipped with a single antenna. To prevent the untrusted relay from intercepting the source message, the destination sends an intended jamming noise to the relay, which is referred to as destination-based cooperative jamming (DBCJ). Given this system model, novel closed-form expressions are presented in the high signal-to-noise ratio (SNR) regime for the ergodic secrecy rate (ESR) and the secrecy outage probability (SOP). We further improve the secrecy performance of the system by optimizing the associated hardware design. The results reveal that by beneficially distributing the tolerable hardware imperfections across the transmission and reception radio-frequency (RF) front ends of each node, the system's secrecy rate may be improved. The engineering insight is that equally sharing the total imperfections at the relay between the transmitter and the receiver provides the best secrecy performance. Numerical results illustrate that the proposed OPA together with the most appropriate hardware design significantly increases the secrecy rate., 29 pages, 7 figures, Submitted to IEEE Transactions on Wireless Communications
- Published
- 2017
11. Jamming-Resilient Frequency Hopping-Aided Secure Communication for Internet-of-Things in the Presence of an Untrusted Relay.
- Author
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Letafati, Mehdi, Kuhestani, Ali, Behroozi, Hamid, and Ng, Derrick Wing Kwan
- Abstract
In this paper, we propose a light-weight jamming-resistant scheme for the Internet-of-Things (IoT) in 5G networks to ensure high-quality communication in a two-hop cooperative network. In the considered system model, a source communicates with a destination in the presence of an untrusted relay and a powerful multi-antenna adversary jammer. The untrusted relay is an authorized necessary helper who may wiretap the confidential information. Meanwhile, the jammer is an external attacker who tries to damage both the training and transmission phases. Different from traditional frequency hopping spread spectrum (FHSS) techniques that require a pre-determined pattern between communicating nodes, in our scheme, the source and destination enjoy the local observations of the two-hop channels. Then they exploit the measured channel as the source of common randomness to generate shared secret keys. By collecting multiple time slots into a frame, the sequence of channels observed in each frame is utilized to specify the adopted FHSS sequence in the next frame. Based on the derived FHSS sequence from the key generation phase, the source starts to transmit its message supporting by the the destination-assisted cooperative jamming (DACJ) technique which prevents the untrusted relay from discovering the secret message. For the mentioned system model, we present new closed-form expressions for characterizing the achievable secret key rate (SKR) and ergodic secrecy rate (ESR) to highlight the efficiency of our proposed scheme compared to the state-of-the-art. We next determine the optimal power allocation (OPA) between the pilot and data transmission phases that maximizes the ESR performance while escaping from jamming attack. Finally, several numerical examples and discussions are presented to gain engineering insights behind the studied communication scenario. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
12. Secure Two-Way Transmission via Wireless-Powered Untrusted Relay and External Jammer
- Author
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Mamaghani, Milad Tatar, Kuhestani, Ali, and Wong, Kai-Kit
- Subjects
Networking and Internet Architecture (cs.NI) ,FOS: Computer and information sciences ,Computer Science - Networking and Internet Architecture ,Computer Science - Cryptography and Security ,Information Theory (cs.IT) ,Computer Science - Information Theory ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,Data_CODINGANDINFORMATIONTHEORY ,Cryptography and Security (cs.CR) ,Computer Science::Information Theory - Abstract
In this paper, we propose a two-way secure communication scheme where two transceivers exchange confidential messages via a wireless powered untrusted amplify-and-forward (AF) relay in the presence of an external jammer. We take into account both friendly jamming (FJ) and Gaussian noise jamming (GNJ) scenarios. Based on the time switching (TS) architecture at the relay, the data transmission is done in three phases. In the first phase, both the energy-starved nodes, the untrustworthy relay and the jammer, are charged by non-information radio frequency (RF) signals from the sources. In the second phase, the two sources send their information signals and concurrently, the jammer transmits artificial noise to confuse the curious relay. Finally, the third phase is dedicated to forward a scaled version of the received signal from the relay to the sources. For the proposed secure transmission schemes, we derive new closed-form lower-bound expressions for the ergodic secrecy sum rate (ESSR) in the high signal-to-noise ratio (SNR) regime. We further analyze the asymptotic ESSR to determine the key parameters; the high SNR slope and the high SNR power offset of the jamming based scenarios. To highlight the performance advantage of the proposed FJ, we also examine the scenario of without jamming (WoJ). Finally, numerical examples and discussions are provided to acquire some engineering insights, and to demonstrate the impacts of different system parameters on the secrecy performance of the considered communication scenarios. The numerical results illustrate that the proposed FJ significantly outperforms the traditional one-way communication and the Constellation rotation approach, as well as our proposed benchmarks, the two-way WoJ and GNJ scenarios., 14 pages, 6 figures, Submitted to IEEE Transactions on Vehicular Technology
- Published
- 2017
13. Three-Hop Untrusted Relay Networks With Hardware Imperfections and Channel Estimation Errors for Internet of Things.
- Author
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Letafati, Mehdi, Kuhestani, Ali, and Behroozi, Hamid
- Abstract
Cooperative relaying can be introduced as a promising approach for data communication in the Internet of Things (IoT), where the source and the destination may be placed far away. In this paper, by taking a variety of realistic hardware imperfections (HWIs) and channels estimation errors (CEEs) into account, the secrecy performance of a three-hop cooperative network with a source, a destination and two consecutive amplify-and-forward (AF) relays is investigated. The relays are considered to be untrusted, i.e., while they are mandatory helpers for data transmission, they may overhear the received signals. We adopt the artificial noise injection scheme, to keep the source message secret from being captured by the untrusted relays. Given this system model, a novel closed-form expression is obtained in the high signal-to-noise ratio (SNR) regime for the ergodic secrecy rate (ESR) performance over Nakagami- $m$ fading. Our simulation results highlight that the secrecy performance of the system is improved when the tolerable HWIs are distributed beneficially across the transmission and reception radio-frequency (RF) front-ends of each node. Our work reveals that unlike the ideal case, the realistic scenario of non-ideal hardware with CEEs faces with the secrecy rate ceiling. Finally, under a constraint on the total energy consumption which is applicable for battery-limited IoT equipment, we maximize the achievable secrecy rate. Our results highlight the importance of the destination’s jamming cooperation and the first relay’s role on the secrecy performance. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
14. Covert Communication and Secure Transmission Over Untrusted Relaying Networks in the Presence of Multiple Wardens.
- Author
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Forouzesh, Moslem, Azmi, Paeiz, Kuhestani, Ali, and Yeoh, Phee Lep
- Subjects
ERROR probability ,ERROR detection (Information theory) ,SECRECY ,CONVEX programming - Abstract
In this paper, we address the problem of joint covert communication and secure transmission in untrusted relaying networks when multiple wardens exist in the network. We first consider a system model consisting of one source, one untrusted amplify-and-forward relay, one destination, and one warden. For covert communications, our aim is to prevent the warden from detecting the presence of communications via the source-relay-destination link. For secure transmission, our aim is to prevent the untrusted relay from decoding the source signal. To satisfy these requirements, we propose that the destination and the source inject jamming signals during the source-to-relay and relay-to-destination transmission phases, respectively. For the considered system model, we propose a power allocation strategy to maximize the secrecy rate and satisfy the covert requirements in both of the phases. Given that the proposed optimization problem is non-convex, we employ the successive convex approximation (SCA) approach to derive a tractable solution. To obtain further insights, we generalize our analytical results to consider multiple untrusted relays and multiple wardens. We focus on two scenarios of non-colluding and colluding wardens. Our results highlight that as the number of relays increases, the achievable secrecy rate increases while the average detection error probability decreases. This is a novel observation of a fundamental trade-off between covert requirement and secrecy performance. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
15. Secure Two-Way Transmission via Wireless-Powered Untrusted Relay and External Jammer.
- Author
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Tatar Mamaghani, Milad, Kuhestani, Ali, and Wong, Kai-Kit
- Subjects
- *
WIRELESS communications , *ELECTRIC interference , *RADIO frequency , *TELECOMMUNICATION systems , *RADIO measurements - Abstract
In this paper, we propose a two-way secure communication scheme where two transceivers exchange confidential messages via a wireless-powered untrusted amplify-and-forward relay in the presence of an external jammer. We take into account both friendly jamming (FJ) and Gaussian noise jamming (GNJ) scenarios. Based on the time switching (TS) architecture at the relay, the data transmission is done in three phases. In the first phase, both the energy-starved nodes, the untrustworthy relay and the jammer, are charged by noninformation radio frequency (RF) signals from the sources. In the second phase, the two sources send their information signals and concurrently, the jammer transmits artificial noise to confuse the curious relay. Finally, the third phase is dedicated to forward a scaled version of the received signal from the relay to the sources. For the proposed secure transmission schemes, we derive new closed-form lower-bound expressions for the ergodic secrecy sum rate (ESSR) in the high signal-to-noise ratio (SNR) regime. We further analyze the asymptotic ESSR to determine the key parameters; the high SNR slope and the high SNR power offset of the jamming based scenarios. To highlight the performance advantage of the proposed FJ, we also examine the scenario of without jamming (WoJ). Finally, numerical examples and discussions are provided to acquire some engineering insights, and to demonstrate the impacts of different system parameters on the secrecy performance of the considered communication scenarios. The numerical results illustrate that the proposed FJ significantly outperforms the traditional one-way communication and the constellation rotation (CR) approach, as well as our proposed benchmarks, the two-way WoJ and GNJ scenarios. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
16. Optimal Power Allocation by Imperfect Hardware Analysis in Untrusted Relaying Networks.
- Author
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Kuhestani, Ali, Mohammadi, Abbas, Wong, Kai-Kit, Yeoh, Phee Lep, Moradikia, Majid, and Khandaker, Muhammad R. A.
- Abstract
By taking a variety of realistic hardware imperfections into consideration, we propose an optimal power allocation (OPA) strategy to maximize the instantaneous secrecy rate of a cooperative wireless network comprised of a source, a destination, and an untrusted amplify-and-forward relay. We assume that either the source or the destination is equipped with a large-scale multiple antennas’ system, while the rest are equipped with a single antenna. To prevent the untrusted relay from intercepting the source message, the destination sends an intended jamming noise to the relay, which is referred to as destination-based cooperative jamming. Given this system model, novel closed-form expressions are presented in the high signal-to-noise ratio regime for the ergodic secrecy rate and the secrecy outage probability. We further improve the secrecy performance of the system by optimizing the associated hardware design. The results reveal that by beneficially distributing the tolerable hardware imperfections across the transmission and reception radio-frequency front ends of each node, the system’s secrecy rate may be improved. The engineering insight is that equally sharing the total imperfections at the relay between the transmitter and the receiver provides the best secrecy performance. Numerical results illustrate that the proposed OPA together with the most appropriate hardware design significantly increases the secrecy rate. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
17. Optimal Power Allocation and Secrecy Sum Rate in Two-Way Untrusted Relaying Networks With an External Jammer.
- Author
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Kuhestani, Ali, Mohammadi, Abbas, and Yeoh, Phee Lep
- Subjects
- *
ELECTRIC relays , *ANTENNAS (Electronics) , *SIGNAL-to-noise ratio , *INTERNET of things , *RANDOM noise theory - Abstract
In this paper, we examine the secrecy performance of two-way relaying between a large-scale multiple antenna base station (BS) and a single antenna mobile user (MU) in the presence of a multiple antenna external jammer. We consider the untrusted relaying scenario, where an amplify-and-forward relay is both a necessary helper and a potential eavesdropper to the BS and MU transmissions. With the aim of maximizing the instantaneous secrecy sum rate, we derive new closed-form solutions for the optimal power allocation (OPA) under the following three scenarios: 1) without jamming (WoJ) where the jammer is not activated; 2) friendly jamming (FJ) where the jamming signal is known a priori at the BS and MU; and 3) Gaussian noise jamming (GNJ) where the jamming signal is unknown at the BS and MU. Based on our OPA solutions, new closed-form expressions are derived for the ergodic secrecy sum rate (ESSR) with Rayleigh fading channels. Furthermore, we characterize the high signal-to-noise ratio slope and power offset of the ESSR to provide a fundamental comparison of the WoJ, FJ, and GNJ scenarios. Based on our analysis, we propose a simple relay selection criterion for the scenario when the BS and MU are assisted by multiple untrusted relays. Numerical examples are presented to demonstrate the impact of the jammer’s location, number of antennas and the advantage of the proposed relay selection criterion on the secrecy performance. Our findings highlight that similar to the trusted relaying scenario, the ESSR of all three secure transmission scenarios improve as the number of untrusted relays increases. Moreover, we highlight an interesting insight that the OPA for the GNJ scenario results in the same ESSR performance as the OPA for the WoJ scenario. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
18. Joint Relay Selection and Power Allocation in Large-Scale MIMO Systems With Untrusted Relays and Passive Eavesdroppers.
- Author
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Kuhestani, Ali, Mohammadi, Abbas, and Mohammadi, Mohammadali
- Abstract
In this paper, a joint relay selection and power allocation (JRP) scheme is proposed to enhance the physical layer security of a cooperative network, where a multiple antennas source communicates with a single-antenna destination in the presence of untrusted relays and passive eavesdroppers (Eves). The objective is to protect the data confidentially while concurrently relying on the untrusted relays as potential Eves to improve both the security and reliability of the network. To realize this objective, we consider cooperative jamming performed by the destination while the JRP scheme is implemented. With the aim of maximizing the instantaneous secrecy rate, we derive a new closed-form solution for the optimal power allocation and propose a simple relay selection criterion under two scenarios of non-colluding Eves (NCE) and colluding Eves (CE). For the proposed scheme, a new closed-form expression is derived for the ergodic secrecy rate (ESR) and the secrecy outage probability as security metrics, and a new closed-form expression is presented for the average symbol error rate as a reliability measure over Rayleigh fading channels. We further explicitly characterize the high signal-to-noise ratio slope and power offset of the ESR to highlight the impacts of system parameters on the ESR. In addition, we examine the diversity order of the proposed scheme to reveal the achievable secrecy performance advantage. Finally, the secrecy and reliability diversity-multiplexing tradeoff of the optimized network are provided. Numerical results highlight that the ESR performance of the proposed JRP scheme for NCE and CE cases is increased with respect to the number of untrustworthy relays. [ABSTRACT FROM PUBLISHER]
- Published
- 2018
- Full Text
- View/download PDF
19. Ergodic sum rate analysis and efficient power allocation for amassive MIMO two-way relay network.
- Author
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Roshandeh, Koosha Pourtahmasi, Kuhestani, Ali, Ardakani, Masoud, and Tellambura, Chintha
- Subjects
- *
ANTENNAS (Electronics) , *SIGNAL-to-noise ratio , *MIMO systems , *NAKAGAMI channels , *COMPUTER simulation - Abstract
The authors study the transmit power allocation (PA) problem for a network of two multi-antenna terminals (one of which is a massivemultiple-input and multiple-output (MIMO) terminal) and a two-way, amplify-and-forward relay. The relay is limited to a single antenna. Using perfect channel state information, the terminals employ beamforming with maximumratio- transmission and maximum-ratio-combining for transmission and reception, respectively. The authors investigate two practical problems, namely; (i) maximising the sum rate subject to a total power constraint (ii) maximising the sumrate when one of the terminals must exceed a target signal-to-noise ratio (SNR). For the first case, the authors derive the closed-form optimal PA and for the second, the authors derive a sub-optimal PA. In both cases, the resulting sum rates are a function of instantaneous channel gains. Thus by averaging over the Nakagami-m distribution and exploiting the weak law of large numbers, the authors derive the closed-form ergodic sum rates. Finally, the simulation results validate the theoretical analysis and show the sum-rate improvements over uniform PA. For example, to achieve 4 bit/s/Hz, a uniform allocation needs 1 dB more than the authors' optimal allocation. When one of the SNRs must exceed a target value, the gap between the authors' sub-optimal PA and random PA increases to 2 dB. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
20. Optimal power allocation to improve secrecy performance of non-regenerative cooperative systems using an untrusted relay.
- Author
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Kuhestani, Ali, Mohammadi, Abbas, and Noori, Moslem
- Subjects
- *
OPTIMAL control theory , *DATA transmission systems , *SIGNAL theory , *SIGNALLING protocols (Telecommunication) , *WIRELESS communications - Abstract
To protect data communication from eavesdropper nodes, different techniques have been developed to improve the physical-layer security (PLS) of communications systems. Destination-based cooperative signalling (DBCS) is one of such techniques where the destination sends an intended artificial noise to the untrusted listeners helping to protect the source message from being captured reliably at eavesdroppers. In this study, the authors investigate the application of DBCS to improve the PLS, and as a consequence the secrecy performance of a two-hop amplify-and-forward cooperative system with an untrusted relay. To get the best performance out of DBCS, the transmit power of the source's signal as well as the artificial noise should be carefully adjusted. To address this, they have introduced the optimal power allocation to maximise the secrecy rate of the system under a sum-power constraint at the network nodes. For a system with large-scale antenna arrays at the base station, then then find the closed-form solution for the secrecy outage probability and the ergodic secrecy rate of the optimised system for both uplink and downlink. The presented simulation results validate the authors' theoretical analysis and reveal that the proposed DBCS with optimal power allocation significantly improves the secrecy performance of the system. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
21. Joint optimal power allocation and relay selection to establish secure transmission in uplink transmission of untrusted relays network.
- Author
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Kuhestani, Ali, Mohammadi, Abbas, and Masoudi, Meysam
- Abstract
In this paper, the authors deal with secure transmission in two‐hop amplify‐and‐forward network with untrusted relays. To prevent the untrusted relays from intercepting the source message and to achieve positive secrecy rate, the destination‐based cooperative jamming technique is used. The authors propose joint secure best relay selection (BRS) and optimal power allocation (OPA) for uplink transmission of a cellular network when the base station is equipped with very large‐scale antenna arrays. Then, the common performance metrics such as ergodic secrecy rate (ESR) and secrecy outage probability are evaluated for the optimised network. Moreover, the diversity order and diversity‐multiplexing tradeoff of the system are examined. The authors obtain that the diversity order of joint BRS and OPA scenario is equal to number of relays. Finally, some numerical and simulation results are presented to validate the theoretical analysis and to show the advantages offered by the presented systems. They reveal interesting results that, by increasing number of untrusted relay nodes, the system performance improves. For example, for target ESR 2 bits/s/Hz and ten untrusted relay nodes, the optimised network saves about 5 dB for uplink transmission, in comparison with the system applying the BRS and equal power allocation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
22. Simple structure efficient full-rate STBC for LTE-Advanced system over correlated Rayleigh fading channel with simple decoder.
- Author
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Kuhestani, Ali and Mohammadi, Abbas
- Published
- 2014
- Full Text
- View/download PDF
23. Finite-SNR diversity-multiplexing tradeoff of linear dispersion coded MISO systems.
- Author
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Kuhestani, Ali and Mohammadi, Abbas
- Published
- 2014
- Full Text
- View/download PDF
24. Efficient full-rate LDCs in correlated Rician fading channel with decoupled decoder.
- Author
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Kuhestani, Ali, Azmi, Paeiz, and PilAram, Hossein
- Published
- 2012
- Full Text
- View/download PDF
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