34,129 research outputs found
Strong Secrecy for Multiple Access Channels
We show strongly secret achievable rate regions for two different wiretap
multiple-access channel coding problems. In the first problem, each encoder has
a private message and both together have a common message to transmit. The
encoders have entropy-limited access to common randomness. If no common
randomness is available, then the achievable region derived here does not allow
for the secret transmission of a common message. The second coding problem
assumes that the encoders do not have a common message nor access to common
randomness. However, they may have a conferencing link over which they may
iteratively exchange rate-limited information. This can be used to form a
common message and common randomness to reduce the second coding problem to the
first one. We give the example of a channel where the achievable region equals
zero without conferencing or common randomness and where conferencing
establishes the possibility of secret message transmission. Both coding
problems describe practically relevant networks which need to be secured
against eavesdropping attacks.Comment: 55 page
Polar Coding for the Cognitive Interference Channel with Confidential Messages
In this paper, we propose a low-complexity, secrecy capacity achieving polar
coding scheme for the cognitive interference channel with confidential messages
(CICC) under the strong secrecy criterion. Existing polar coding schemes for
interference channels rely on the use of polar codes for the multiple access
channel, the code construction problem of which can be complicated. We show
that the whole secrecy capacity region of the CICC can be achieved by simple
point-to-point polar codes due to the cognitivity, and our proposed scheme
requires the minimum rate of randomness at the encoder
On Strong Secrecy for Multiple Access Channel with States and Causal CSI
Strong secrecy communication over a discrete memoryless state-dependent
multiple access channel (SD-MAC) with an external eavesdropper is investigated.
The channel is governed by discrete memoryless and i.i.d. channel states and
the channel state information (CSI) is revealed to the encoders in a causal
manner. An inner bound of the capacity is provided. To establish the inner
bound, we investigate coding schemes incorporating wiretap coding and secret
key agreement between the sender and the legitimate receiver. Two kinds of
block Markov coding schemes are studied. The first one uses backward decoding
and Wyner-Ziv coding and the secret key is constructed from a lossy
reproduction of the CSI. The other one is an extended version of the existing
coding scheme for point-to-point wiretap channels with causal CSI. We further
investigate some capacity-achieving cases for state-dependent multiple access
wiretap channels (SD-MAWCs) with degraded message sets. It turns out that the
two coding schemes are both optimal in these cases.Comment: Accepted for presentation at ISIT202
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
Weak Secrecy in the Multi-Way Untrusted Relay Channel with Compute-and-Forward
We investigate the problem of secure communications in a Gaussian multi-way
relay channel applying the compute-and-forward scheme using nested lattice
codes. All nodes employ half-duplex operation and can exchange confidential
messages only via an untrusted relay. The relay is assumed to be honest but
curious, i.e., an eavesdropper that conforms to the system rules and applies
the intended relaying scheme. We start with the general case of the
single-input multiple-output (SIMO) L-user multi-way relay channel and provide
an achievable secrecy rate region under a weak secrecy criterion. We show that
the securely achievable sum rate is equivalent to the difference between the
computation rate and the multiple access channel (MAC) capacity. Particularly,
we show that all nodes must encode their messages such that the common
computation rate tuple falls outside the MAC capacity region of the relay. We
provide results for the single-input single-output (SISO) and the
multiple-input single-input (MISO) L-user multi-way relay channel as well as
the two-way relay channel. We discuss these results and show the dependency
between channel realization and achievable secrecy rate. We further compare our
result to available results in the literature for different schemes and show
that the proposed scheme operates close to the compute-and-forward rate without
secrecy.Comment: submitted to JSAC Special Issue on Fundamental Approaches to Network
Coding in Wireless Communication System
Securing Downlink Non-Orthogonal Multiple Access Systems by Trusted Relays
A downlink single-input single-output non-orthogonal multiple access system
is considered in which a base station (BS) is communicating with two legitimate
users in the presence of an external eavesdropper. A group of trusted
cooperative half-duplex relay nodes, powered by the BS, is employed to assist
the BS's transmission. The goal is to design relaying schemes such that the
legitimate users' secrecy rate region is maximized subject to a total power
constraint on the BS and the relays' transmissions. Three relaying schemes are
investigated: cooperative jamming, decode-and-forward, and amplify-and-forward.
Depending on the scheme, secure beamforming signals are carefully designed for
the relay nodes that either diminish the eavesdropper's rate without affecting
that of the legitimate users, or increase the legitimate users' rates without
increasing that of the eavesdropper. The results show that there is no relaying
scheme that fits all conditions; the best relaying scheme depends on the system
parameters, namely, the relays' and eavesdropper's distances from the BS, and
the number of relays. They also show that the relatively simple cooperative
jamming scheme outperforms other schemes when the relays are far from the BS
and/or close to the eavesdropper.Comment: To appear in IEEE Globecom 201
- …