424 research outputs found
Secure Satellite Communication Systems Design with Individual Secrecy Rate Constraints
In this paper, we study multibeam satellite secure communication through
physical (PHY) layer security techniques, i.e., joint power control and
beamforming. By first assuming that the Channel State Information (CSI) is
available and the beamforming weights are fixed, a novel secure satellite
system design is investigated to minimize the transmit power with individual
secrecy rate constraints. An iterative algorithm is proposed to obtain an
optimized power allocation strategy. Moreover, sub-optimal beamforming weights
are obtained by completely eliminating the co-channel interference and nulling
the eavesdroppers' signal simultaneously. In order to obtain jointly optimized
power allocation and beamforming strategy in some practical cases, e.g., with
certain estimation errors of the CSI, we further evaluate the impact of the
eavesdropper's CSI on the secure multibeam satellite system design. The
convergence of the iterative algorithm is proven under justifiable assumptions.
The performance is evaluated by taking into account the impact of the number of
antenna elements, number of beams, individual secrecy rate requirement, and
CSI. The proposed novel secure multibeam satellite system design can achieve
optimized power allocation to ensure the minimum individual secrecy rate
requirement. The results show that the joint beamforming scheme is more
favorable than fixed beamforming scheme, especially in the cases of a larger
number of satellite antenna elements and higher secrecy rate requirement.
Finally, we compare the results under the current satellite air-interface in
DVB-S2 and the results under Gaussian inputs.Comment: 34 pages, 10 figures, 1 table, submitted to "Transactions on
Information Forensics and Security
Directional Modulation via Symbol-Level Precoding: A Way to Enhance Security
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 multi-user MIMO communication
systems when a multi-antenna eavesdropper is present. Enhancing the security 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 non-negative 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.Comment: This manuscript is submitted to IEEE Journal of Selected Topics in
Signal Processin
UAV Swarm-Enabled Aerial CoMP: A Physical Layer Security Perspective
Unlike aerial base station enabled by a single unmanned aerial vehicle (UAV),
aerial coordinated multiple points (CoMP) can be enabled by a UAV swarm. In
this case, the management of multiple UAVs is important. This paper considers
the power allocation strategy for a UAV swarm-enabled aerial network to enhance
the physical layer security of the downlink transmission, where an eavesdropper
moves following the trajectory of the swarm for better eavesdropping. Unlike
existing works, we use only the large-scale channel state information (CSI) and
maximize the secrecy throughput in a whole-trajectory-oriented manner. The
overall transmission energy constraint on each UAV and the total transmission
duration for all the legitimate users are considered. The non-convexity of the
formulated problem is solved by using max-min optimization with iteration. Both
the transmission power of desired signals and artificial noise (AN) are derived
iteratively. Simulation results are presented to validate the effectiveness of
our proposed power allocation algorithm and to show the advantage of aerial
CoMP by using only the large-scale CSI
Symbol-Level Multiuser MISO Precoding for Multi-level Adaptive Modulation
Symbol-level precoding is a new paradigm for multiuser downlink systems which
aims at creating constructive interference among the transmitted data streams.
This can be enabled by designing the precoded signal of the multiantenna
transmitter on a symbol level, taking into account both channel state
information and data symbols. Previous literature has studied this paradigm for
MPSK modulations by addressing various performance metrics, such as power
minimization and maximization of the minimum rate. In this paper, we extend
this to generic multi-level modulations i.e. MQAM and APSK by establishing
connection to PHY layer multicasting with phase constraints. Furthermore, we
address adaptive modulation schemes which are crucial in enabling the
throughput scaling of symbol-level precoded systems. In this direction, we
design signal processing algorithms for minimizing the required power under
per-user SINR or goodput constraints. Extensive numerical results show that the
proposed algorithm provides considerable power and energy efficiency gains,
while adapting the employed modulation scheme to match the requested data rate
On the secrecy performance of land mobile satellite communication systems
In this paper, we investigate the secrecy performance against eavesdropping of a land mobile satellite (LMS) system, where the satellite employs the spot beam technique, and both the terrestrial user and eavesdropper are equipped with multiple antennas and utilize maximal ratio combining (MRC) to receive the confidential message. Specifically, in terms of the availability of the eavesdropper’s CSI at the satellite, we consider both passive (Scenario I) and active (Scenario II) eavesdropping. For Scenario I where the eavesdropper’s channel state information (CSI) is unknown to the satellite, closed-form expressions for the probability of non-zero secrecy capacity and secrecy outage probability are derived. Furthermore, expressions for the asymptotic secrecy outage probability are also presented to reveal the secrecy diversity order and array gain of the considered system. For Scenario II where the eavesdropper’s CSI is available at the satellite, novel expressions for the exact and asymptotic average secrecy capacity are obtained. Based on a simple asymptotic formula, we can characterize the high signalto- noise ratio (SNR) slope and high SNR power offset of the LMS systems. Finally, simulations are provided to validate our theoretical analysis and show the effect of different parameters on the system performance
Secrecy Analysis on Network Coding in Bidirectional Multibeam Satellite Communications
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 schem
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