| 1. |
- Kalantari, A., et al.
(författare)
-
Directional Modulation Via Symbol-Level Precoding : A Way to Enhance Security
- 2016
-
Ingår i: IEEE Journal on Selected Topics in Signal Processing. - : Institute of Electrical and Electronics Engineers (IEEE). - 1932-4553 .- 1941-0484. ; 10:8, s. 1478-1493
-
Tidskriftsartikel (refereegranskat)abstract
- Wireless communication provides a wide coverage at the cost of exposing information to unintended users. As an information-theoretic paradigm, secrecy rate derives bounds for secure transmission when the channel to the eavesdropper is known. However, such bounds are shown to be restrictive in practice and may require exploitation of specialized coding schemes. In this paper, we employ the concept of directional modulation and follow a signal processing approach to enhance the security of multiuser multi-input multioutput (MIMO) communication systems when a multiantenna eavesdropper is present. Security enhancement is accomplished by increasing the symbol error rate at the eavesdropper. Unlike the information-theoretic secrecy rate paradigm, we assume that the legitimate transmitter is not aware of its channel to the eavesdropper, which is a more realistic assumption. We examine the applicability of MIMO receiving algorithms at the eavesdropper. Using the channel knowledge and the intended symbols for the users, we design security enhancing symbol-level precoders for different transmitter and eavesdropper antenna configurations. We transform each design problem to a linearly constrained quadratic program and propose two solutions, namely the iterative algorithm and one based on nonnegative least squares, at each scenario for a computationally efficient modulation. Simulation results verify the analysis and show that the designed precoders outperform the benchmark scheme in terms of both power efficiency and security enhancement.
|
|
| 2. |
- Kalantari, A., et al.
(författare)
-
Secrecy Analysis on Network Coding in Bidirectional Multibeam Satellite Communications
- 2015
-
Ingår i: IEEE Transactions on Information Forensics and Security. - : Institute of Electrical and Electronics Engineers (IEEE). - 1556-6013 .- 1556-6021. ; 10:9, s. 1862-1874
-
Tidskriftsartikel (refereegranskat)abstract
- Network coding is an efficient means to improve the spectrum efficiency of satellite communications. However, its resilience to eavesdropping attacks is not well understood. This paper studies the confidentiality issue in a bidirectional satellite network consisting of two mobile users who want to exchange message via a multibeam satellite using the XOR network coding protocol. We aim to maximize the sum secrecy rate by designing the optimal beamforming vector along with optimizing the return and forward link time allocation. The problem is nonconvex, and we find its optimal solution using semidefinite programming together with a 1-D search. For comparison, we also solve the sum secrecy rate maximization problem for a conventional reference scheme without using network coding. Simulation results using realistic system parameters demonstrate that the bidirectional scheme using network coding provides considerably higher secrecy rate compared with that of the conventional scheme.
|
|
| 3. |
- Maleki, S., et al.
(författare)
-
Power allocation for energy-constrained cognitive radios in the presence of an eavesdropper
- 2014
-
Ingår i: 2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - : IEEE conference proceedings. ; , s. 5695-5699
-
Konferensbidrag (refereegranskat)abstract
- Reliable and agile spectrum sensing as well as secure communication are key requirements of a cognitive radio system. In this paper, secrecy throughput of a cognitive radio is maximized in order to determine the sensing threshold, the sensing time, and the transmission power. Constraints of the problem are defined as a lower-bound on the detection probability, an upper-bound on the average energy consumption per time-frame, and the maximum transmission power of the cognitive radio. We show that the problem can be solved by an on-off strategy where the cognitive radio only performs sensing and transmits data if the cognitive channel gain is greater than the average eavesdropper channel gain. The problem is then solved by a line-search over sensing time. Eventually, the secrecy throughput of the cognitive radio is evaluated employing the IEEE 802.15.4/Zig-Bee standard.
|
|
| 4. |
|
|
