47 research outputs found
LDPC coded transmissions over the Gaussian broadcast channel with confidential messages
We design and assess some practical low-density parity-check (LDPC) coded
transmission schemes for the Gaussian broadcast channel with confidential
messages (BCC). This channel model is different from the classical wiretap
channel model as the unauthorized receiver (Eve) must be able to decode some
part of the information. Hence, the reliability and security targets are
different from those of the wiretap channel. In order to design and assess
practical coding schemes, we use the error rate as a metric of the performance
achieved by the authorized receiver (Bob) and the unauthorized receiver (Eve).
We study the system feasibility, and show that two different levels of
protection against noise are required on the public and the secret messages.
This can be achieved in two ways: i) by using LDPC codes with unequal error
protection (UEP) of the transmitted information bits or ii) by using two
classical non-UEP LDPC codes with different rates. We compare these two
approaches and show that, for the considered examples, the solution exploiting
UEP LDPC codes is more efficient than that using non-UEP LDPC codes.Comment: 5 pages, 5 figures, to be presented at IEEE ICT 201
An Overview of Physical Layer Security with Finite-Alphabet Signaling
Providing secure communications over the physical layer with the objective of
achieving perfect secrecy without requiring a secret key has been receiving
growing attention within the past decade. The vast majority of the existing
studies in the area of physical layer security focus exclusively on the
scenarios where the channel inputs are Gaussian distributed. However, in
practice, the signals employed for transmission are drawn from discrete signal
constellations such as phase shift keying and quadrature amplitude modulation.
Hence, understanding the impact of the finite-alphabet input constraints and
designing secure transmission schemes under this assumption is a mandatory step
towards a practical implementation of physical layer security. With this
motivation, this article reviews recent developments on physical layer security
with finite-alphabet inputs. We explore transmit signal design algorithms for
single-antenna as well as multi-antenna wiretap channels under different
assumptions on the channel state information at the transmitter. Moreover, we
present a review of the recent results on secure transmission with discrete
signaling for various scenarios including multi-carrier transmission systems,
broadcast channels with confidential messages, cognitive multiple access and
relay networks. Throughout the article, we stress the important behavioral
differences of discrete versus Gaussian inputs in the context of the physical
layer security. We also present an overview of practical code construction over
Gaussian and fading wiretap channels, and we discuss some open problems and
directions for future research.Comment: Submitted to IEEE Communications Surveys & Tutorials (1st Revision
Polar Coding for the Large Hadron Collider: Challenges in Code Concatenation
In this work, we present a concatenated repetition-polar coding scheme that
is aimed at applications requiring highly unbalanced unequal bit-error
protection, such as the Beam Interlock System of the Large Hadron Collider at
CERN. Even though this concatenation scheme is simple, it reveals significant
challenges that may be encountered when designing a concatenated scheme that
uses a polar code as an inner code, such as error correlation and unusual
decision log-likelihood ratio distributions. We explain and analyze these
challenges and we propose two ways to overcome them.Comment: Presented at the 51st Asilomar Conference on Signals, Systems, and
Computers, November 201
Practical LDPC coded modulation schemes for the fading broadcast channel with confidential messages
The broadcast channel with confidential messages is a well studied scenario
from the theoretical standpoint, but there is still lack of practical schemes
able to achieve some fixed level of reliability and security over such a
channel. In this paper, we consider a quasi-static fading channel in which both
public and private messages must be sent from the transmitter to the receivers,
and we aim at designing suitable coding and modulation schemes to achieve such
a target. For this purpose, we adopt the error rate as a metric, by considering
that reliability (security) is achieved when a sufficiently low (high) error
rate is experienced at the receiving side. We show that some conditions exist
on the system feasibility, and that some outage probability must be tolerated
to cope with the fading nature of the channel. The proposed solution exploits
low-density parity-check codes with unequal error protection, which are able to
guarantee two different levels of protection against noise for the public and
the private information, in conjunction with different modulation schemes for
the public and the private message bits.Comment: 6 pages, 4 figures, to be presented at IEEE ICC'14 - Workshop on
Wireless Physical Layer Securit
A Survey of Physical Layer Security Techniques for 5G Wireless Networks and Challenges Ahead
Physical layer security which safeguards data confidentiality based on the
information-theoretic approaches has received significant research interest
recently. The key idea behind physical layer security is to utilize the
intrinsic randomness of the transmission channel to guarantee the security in
physical layer. The evolution towards 5G wireless communications poses new
challenges for physical layer security research. This paper provides a latest
survey of the physical layer security research on various promising 5G
technologies, including physical layer security coding, massive multiple-input
multiple-output, millimeter wave communications, heterogeneous networks,
non-orthogonal multiple access, full duplex technology, etc. Technical
challenges which remain unresolved at the time of writing are summarized and
the future trends of physical layer security in 5G and beyond are discussed.Comment: To appear in IEEE Journal on Selected Areas in Communication
Learning End-to-End Codes for the BPSK-constrained Gaussian Wiretap Channel
Finite-length codes are learned for the Gaussian wiretap channel in an
end-to-end manner assuming that the communication parties are equipped with
deep neural networks (DNNs), and communicate through binary phase-shift keying
(BPSK) modulation scheme. The goal is to find codes via DNNs which allow a pair
of transmitter and receiver to communicate reliably and securely in the
presence of an adversary aiming at decoding the secret messages. Following the
information-theoretic secrecy principles, the security is evaluated in terms of
mutual information utilizing a deep learning tool called MINE (mutual
information neural estimation). System performance is evaluated for different
DNN architectures, designed based on the existing secure coding schemes, at the
transmitter. Numerical results demonstrate that the legitimate parties can
indeed establish a secure transmission in this setting as the learned codes
achieve points on almost the boundary of the equivocation region
Polar codes : construction and performance improvement
Recently, Erdal Arikan proposed a method “channel polarization” and then
introduced polar codes based on this method. Polar codes are a breakthrough
in coding theory because they are the first kind of codes to be proved to achieve
capacity for a wide range of channels with linear encoding and decoding complexity
O(N logN), where N is the blocklength of the code. In this work we
investigate the construction of polar codes under additive white Gaussian noise
(AWGN) channel and then improve their performance.
The first problem we consider is the construction of polar codes under AWGN
channel. In specific, polar codes are constructed based on Gaussian approximation.
The formula of calculating Bhattacharyya parameter is also derived. The
performance and implementation complexity of our scheme and the existing
schemes are compared. Results show that the polar codes we construct are efficient,
practical and achieve a good tradeoff between decoding performance and
implementation complexity.
To further improve the error performance, turbo polar codes are proposed.
Turbo polar codes are constructed by concatenating two polar codes parallelly.
An iterative decoding method is adopted to decode turbo polar codes. The
encoder and decoder of turbo polar codes are designed. Besides, we analyze the
performance of turbo polar codes by considering the effect of iteration number,
interleaver size and different decoding algorithms. Moreover, the interleaver
structure is devised to improve the performance. Finally, we compare turbo
polar codes with polar codes and show that turbo polar codes achieve a better performance
An Overview of Physical Layer Security with Finite Alphabet Signaling
Providing secure communications over the physical layer with the objective of achieving secrecy without requiring a secret key has been receiving growing attention within the past decade. The vast majority of the existing studies in the area of physical layer security focus exclusively on the scenarios where the channel inputs are Gaussian distributed. However, in practice, the signals employed for transmission are drawn from discrete signal constellations such as phase shift keying and quadrature amplitude modulation. Hence, understanding the impact of the finite-alphabet input constraints and designing secure transmission schemes under this assumption is a mandatory step towards a practical implementation of physical layer security. With this motivation, this article reviews recent developments on physical layer security with finite-alphabet inputs. We explore transmit signal design algorithms for single-antenna as well as multi-antenna wiretap channels under different assumptions on the channel state information at the transmitter. Moreover, we present a review of the recent results on secure transmission with discrete signaling for various scenarios including multi-carrier transmission systems, broadcast channels with confidential messages, cognitive multiple access and relay networks. Throughout the article, we stress the important behavioral differences of discrete versus Gaussian inputs in the context of the physical layer security. We also present an overview of practical code construction over Gaussian and fading wiretap channels, and discuss some open problems and directions for future research