This paper presents secrecy analyses of a full-duplex MIMOME network which consists of two full-duplex multi-antenna users (Alice and Bob) and an arbitrarily located multi-antenna eavesdropper (Eve). The paper assumes that Eve's channel state information (CSI) is completely unknown to Alice and Bob except for a small radius of secured zone. The first part of this paper aims to optimize the powers of jamming noises from both users. To handle Eve's CSI being unknown to users, the focus is placed on Eve at the most harmful location, and the large matrix theory is applied to yield a hardened secrecy rate to work on. The performance gain of the power optimization in terms of maximum tolerable number of antennas on Eve is shown to be significant. The second part of this paper shows two analyses of anti-eavesdropping channel estimation (ANECE) that can better handle Eve with any number of antennas. One analysis assumes that Eve has a prior statistical knowledge of its CSI, which yields lower and upper bounds on secure degrees of freedom of the system as functions of the number (N) of antennas on Eve and the size (K) of information packet. The second analysis assumes that Eve does not have any prior knowledge of its CSI but performs blind detection of information, which yields an approximate secrecy rate for the case of K being larger than N.
This paper presents secrecy analyses of a full-duplex MIMOME network which consists of two full-duplex multi-antenna users (Alice and Bob) and an arbitrarily located multi-antenna eavesdropper (Eve). The paper assumes that Eve's channel state information (CSI) is completely unknown to Alice and Bob except for a small radius of secured zone. The first part of this paper aims to optimize the powers of jamming noises from both users. To handle Eve's CSI being unknown to users, the focus is placed on Eve at the most harmful location, and the large matrix theory is applied to yield a hardened secrecy rate to work on. The performance gain of the power optimization in terms of maximum tolerable number of antennas on Eve is shown to be significant. The second part of this paper shows two analyses of anti-eavesdropping channel estimation (ANECE) that can better handle Eve with any number of antennas. One analysis assumes that Eve has a prior statistical knowledge of its CSI, which yields lower and upper bounds on secure degrees of freedom of the system as functions of the number (N) of antennas on Eve and the size (K) of information packet. The second analysis assumes that Eve does not have any prior knowledge of its CSI but performs blind detection of information, which yields an approximate secrecy rate for the case of K being larger than N.
This paper examines the role of full-duplex radio for securing wireless network from a new perspective. It first studies the secrecy capacity of two single-antenna full-duplex users against a multi-antenna eavesdropper (Eve) who has the perfect knowledge of the channel state information (CSI) from users to Eve. It is shown that if Eve uses a basic matched-filtering, the probability of zero secrecy (or outage) can be made small by a large jamming power from both users and a small gain of residual self-interference (RSI) power. But if Eve uses the optimal matched-filtering, the probability of outage grows rapidly as either the jamming power from the users increases or the number of antennas on Eve increases, regardless of the RSI gain. To prevent any Eve from obtaining its CSI, this paper then proposes a novel anti-eavesdropping channel estimation (ANECE) method, which allows users to obtain their own CSI while keeping all Eves in handicap. This method also prevents Eves from colluding with each other at any layer. The design of ideal pilots for ANECE for multiple multi-antenna users and multiple broadband multi-antenna users is discussed. It is also shown that the capacity of Eve with any number of antennas but without its CSI can be virtually eliminated over a time window corresponding to the number of antennas at the transmitter for each realization of the CSI.
This study investigates a secure wireless communication scheme which combines two of the most effective strategies to combat (passive) eavesdropping, namely mixing information with artificial noise at the transmitter and jamming from a full-duplex receiver. All nodes are assumed to possess multiple antennas, which is known as a MIMOME network. The channel state information (CSI) of Eve is known to Eve but not to Alice and Bob. While such setup has been investigated in related works, new and important insights are revealed in this work. We investigate the design of optimal jamming parameters to achieve higher secrecy, and in particular we focus on two important cases corresponding to Bob using either a simple jamming or a smart jamming. Furthermore, simulations are presented to highlight the effectiveness of the proposed strategies.
As the technology and computing power advance day by day, physical layer security in wireless communications gains more importance. It allows the security of wireless communications based on information theoretical guarantees without the need for cryptography. One important practical challenge for physical layer security arises from the fact that no information about the passive eavesdroppers is available to the legitimate nodes. Without such information, optimizing the transmission parameters has always been a difficult task. In this study we aim to address various challenging aspects about this issue and propose a new perspective into the analysis of secrecy with a focus on jamming. We start from the case of eavesdropper's channel state information (CSI) known to users in a three-node single-antenna multi-subcarrier network and present an improved optimization algorithm compared to previous methods. Then we expand our horizon to the case of multiple-antenna nodes with eavesdropper's CSI unknown to users. We investigate a secure wireless communication scheme which combines two of the most effective strategies to combat eavesdropping, namely mixing information with artificial noise at the transmitter and jamming from a full-duplex receiver. While such setup has been investigated in related works, new and important insights are revealed in this study. We investigate the design of optimal jamming parameters to achieve higher secrecy.We then derive a closed-form expression for asymptotic normalized instantaneous secrecy rate of our model. Based on the results of the asymptotic analysis, we propose an alternative less complex tractable optimization problem for the design of optimal transmission parameters to achieve higher secrecy. We show that even with the optimal parameters, secrecy is compromised if Eve is able to increase her number of antennas. To address this issue, we provide a comprehensive analysis of a new scheme called anti-eavesdropping channel estimation (ANECE) which prevents Eve from acquiring accurate channel estimations. We show that the usage of such scheme, makes it extremely hard for Eve to drive secrecy to zero. Numerical analyses and simulations are presented to support the arguments made in this study.We then derive a closed-form expression for asymptotic normalized instantaneous secrecy rate of our model. Based on the results of the asymptotic analysis, we propose an alternative less complex tractable optimization problem for the design of optimal transmission parameters to achieve higher secrecy. We show that even with the optimal parameters, secrecy is compromised if Eve is able to increase her number of antennas. To address this issue, we provide a comprehensive analysis of a new scheme called anti-eavesdropping channel estimation (ANECE) which prevents Eve from acquiring accurate channel estimations. We show that the usage of such scheme, makes it extremely hard for Eve to drive secrecy to zero. Numerical analyses and simulations are presented to support the arguments made in this study.We then derive a closed-form expression for asymptotic normalized instantaneous secrecy rate of our model. Based on the results of the asymptotic analysis, we propose an alternative less complex tractable optimization problem for the design of optimal transmission parameters to achieve higher secrecy. We show that even with the optimal parameters, secrecy is compromised if Eve is able to increase her number of antennas. To address this issue, we provide a comprehensive analysis of a new scheme called anti-eavesdropping channel estimation (ANECE) which prevents Eve from acquiring accurate channel estimations. We show that the usage of such scheme makes it extremely hard for Eve to drive secrecy to zero. Numerical analyses and simulations are presented to support the arguments made in this study.
This paper presents a number of fundamental properties of full-duplex radio for secure wireless communication under some simple and practical conditions. In particular, we consider the fields of secrecy capacity of a wireless channel between two single-antenna radios (Alice and Bob) against an unknown number of single-antenna eavesdroppers (Eves) from unknown locations, where Alice and Bob have zero knowledge (except a model) of the large-scale-fading channel-state-information of Eves. These properties show how the secrecy capacity is distributed in terms of the location of any Eve, how the optimal jamming power applied by the full-duplex radio varies with various parameters, and how bad or good the worst cases are. In particular, these properties show how the quality of self-interference cancelation/suppression affects various aspects of the fields of secrecy capacity. The cases of colluding Eves and non-colluding Eves are treated separately and yet coherently. For non-colluding Eves, asymptotically constant fields of secrecy capacity are revealed. For each of the two cases, we also treat subcases with or without small-scale fading.
In this paper, we consider a two-way wiretap channel in the presence of Multi-Input Multi-Output Multi-antenna Eve (MIMOME), where both nodes (Alice and Bob) transmit and receive in an in-band full-duplex manner and Eve tries to decode the information exchanged between Alice and Bob. For this system with keyless security, we provide artificial noise (AN) based signal design while assuming AN to be known/unknown at the receivers (Alice and Bob). Power allocation problems are formulated with the objective of maximization of sum secrecy rates subject to the transmit power constraint. Accounting for non-ideal self-interference cancellation, a successive convex approximation-based algorithm for the solution for the cases of full CSI, and limited CSI knowledge, including partial information at Eve. For the limited CSI case, numerical ergodic rates are optimized. Simulation results show that with power constraints satisfied, secrecy rates are maximized, and with only partial information at Eve, secrecy rates are improved accordingly.
In this paper, considering a two-way wiretap channel in the Multi-Input Multi-Output Multi-antenna Eve (MIMOME) channel, where both nodes (Alice and Bob) operate in full-duplex manner. For this system, we consider artificial noise (AN) based signal design and derive secrecy rate approximation based on mean-squared error (MSE) upper bound. Statistical power allocation problem is formulated in terms of an optimization problem with the maximization of Alice and Bob rates subject to the rate constraint at Eavesdropper (Eve). The usefulness of the resulting solution is verified via simulations. The results shows that with proper power allocation, Eve rates are significantly lower, and the Alice-Bob sum rates are close to the maximum rate, which are achieved, when the allowable Eve’s rates are increased.