67 research outputs found
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
On the Construction of Polar Codes for Achieving the Capacity of Marginal Channels
Achieving security against adversaries with unlimited computational power is
of great interest in a communication scenario. Since polar codes are capacity
achieving codes with low encoding-decoding complexity and they can approach
perfect secrecy rates for binary-input degraded wiretap channels in symmetric
settings, they are investigated extensively in the literature recently. In this
paper, a polar coding scheme to achieve secrecy capacity in non-symmetric
binary input channels is proposed. The proposed scheme satisfies security and
reliability conditions. The wiretap channel is assumed to be stochastically
degraded with respect to the legitimate channel and message distribution is
uniform. The information set is sent over channels that are good for Bob and
bad for Eve. Random bits are sent over channels that are good for both Bob and
Eve. A frozen vector is chosen randomly and is sent over channels bad for both.
We prove that there exists a frozen vector for which the coding scheme
satisfies reliability and security conditions and approaches the secrecy
capacity. We further empirically show that in the proposed scheme for
non-symmetric binary-input discrete memoryless channels, the equivocation rate
achieves its upper bound in the whole capacity-equivocation region
Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey
This paper provides a comprehensive review of the domain of physical layer
security in multiuser wireless networks. The essential premise of
physical-layer security is to enable the exchange of confidential messages over
a wireless medium in the presence of unauthorized eavesdroppers without relying
on higher-layer encryption. This can be achieved primarily in two ways: without
the need for a secret key by intelligently designing transmit coding
strategies, or by exploiting the wireless communication medium to develop
secret keys over public channels. The survey begins with an overview of the
foundations dating back to the pioneering work of Shannon and Wyner on
information-theoretic security. We then describe the evolution of secure
transmission strategies from point-to-point channels to multiple-antenna
systems, followed by generalizations to multiuser broadcast, multiple-access,
interference, and relay networks. Secret-key generation and establishment
protocols based on physical layer mechanisms are subsequently covered.
Approaches for secrecy based on channel coding design are then examined, along
with a description of inter-disciplinary approaches based on game theory and
stochastic geometry. The associated problem of physical-layer message
authentication is also introduced briefly. The survey concludes with
observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with
arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials,
201
Rate-Equivocation Optimal Spatially Coupled LDPC Codes for the BEC Wiretap Channel
We consider transmission over a wiretap channel where both the main channel
and the wiretapper's channel are Binary Erasure Channels (BEC). We use
convolutional LDPC ensembles based on the coset encoding scheme. More
precisely, we consider regular two edge type convolutional LDPC ensembles. We
show that such a construction achieves the whole rate-equivocation region of
the BEC wiretap channel.
Convolutional LDPC ensemble were introduced by Felstr\"om and Zigangirov and
are known to have excellent thresholds. Recently, Kudekar, Richardson, and
Urbanke proved that the phenomenon of "Spatial Coupling" converts MAP threshold
into BP threshold for transmission over the BEC.
The phenomenon of spatial coupling has been observed to hold for general
binary memoryless symmetric channels. Hence, we conjecture that our
construction is a universal rate-equivocation achieving construction when the
main channel and wiretapper's channel are binary memoryless symmetric channels,
and the wiretapper's channel is degraded with respect to the main channel.Comment: Working pape
Polar Coding for Achieving the Capacity of Marginal Channels in Nonbinary-Input Setting
Achieving information-theoretic security using explicit coding scheme in
which unlimited computational power for eavesdropper is assumed, is one of the
main topics is security consideration. It is shown that polar codes are
capacity achieving codes and have a low complexity in encoding and decoding. It
has been proven that polar codes reach to secrecy capacity in the binary-input
wiretap channels in symmetric settings for which the wiretapper's channel is
degraded with respect to the main channel. The first task of this paper is to
propose a coding scheme to achieve secrecy capacity in asymmetric
nonbinary-input channels while keeping reliability and security conditions
satisfied. Our assumption is that the wiretap channel is stochastically
degraded with respect to the main channel and message distribution is
unspecified. The main idea is to send information set over good channels for
Bob and bad channels for Eve and send random symbols for channels that are good
for both. In this scheme the frozen vector is defined over all possible choices
using polar codes ensemble concept. We proved that there exists a frozen vector
for which the coding scheme satisfies reliability and security conditions. It
is further shown that uniform distribution of the message is the necessary
condition for achieving secrecy capacity.Comment: Accepted to be published in "51th Conference on Information Sciences
and Systems", Baltimore, Marylan
Private Quantum Coding for Quantum Relay Networks
The relay encoder is an unreliable probabilistic device which is aimed at
helping the communication between the sender and the receiver. In this work we
show that in the quantum setting the probabilistic behavior can be completely
eliminated. We also show how to combine quantum polar encoding with
superactivation-assistance in order to achieve reliable and capacity-achieving
private communication over noisy quantum relay channels.Comment: 15 pages, 3 figures, Journal-ref: Lecture Notes in Computer Science,
Vol. 7479, pp. 239-250. Springer-Verlag, 2012, presented in part at the 11th
Intl. Conference on Quantum Communication, Measurement and Computing
(QCMC2012), v2: minor formatting change
Low-resolution ADC receiver design, MIMO interference cancellation prototyping, and PHY secrecy analysis.
This dissertation studies three independent research topics in the general field of wireless communications. The first topic focuses on new receiver design with low-resolution analog-to-digital converters (ADC). In future massive multiple-input-multiple-output (MIMO) systems, multiple high-speed high-resolution ADCs will become a bottleneck for practical applications because of the hardware complexity and power consumption. One solution to this problem is to adopt low-cost low-precision ADCs instead. In Chapter II, MU-MIMO-OFDM systems only equipped with low-precision ADCs are considered. A new turbo receiver structure is proposed to improve the overall system performance. Meanwhile, ultra-low-cost communication devices can enable massive deployment of disposable wireless relays. In Chapter III, the feasibility of using a one-bit relay cluster to help a power-constrained transmitter for distant communication is investigated. Nonlinear estimators are applied to enable effective decoding. The second topic focuses prototyping and verification of a LTE and WiFi co-existence system, where the operation of LTE in unlicensed spectrum (LTE-U) is discussed. LTE-U extends the benefits of LTE and LTE Advanced to unlicensed spectrum, enabling mobile operators to offload data traffic onto unlicensed frequencies more efficiently and effectively. With LTE-U, operators can offer consumers a more robust and seamless mobile broadband experience with better coverage and higher download speeds. As the coexistence leads to considerable performance instability of both LTE and WiFi transmissions, the LTE and WiFi receivers with MIMO interference canceller are designed and prototyped to support the coexistence in Chapter IV. The third topic focuses on theoretical analysis of physical-layer secrecy with finite blocklength. Unlike upper layer security approaches, the physical-layer communication security can guarantee information-theoretic secrecy. Current studies on the physical-layer secrecy are all based on infinite blocklength. Nevertheless, these asymptotic studies are unrealistic and the finite blocklength effect is crucial for practical secrecy communication. In Chapter V, a practical analysis of secure lattice codes is provided
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