18,004 research outputs found
Capacity Bounds for Broadcast Channels with Confidential Messages
In this paper, we study capacity bounds for discrete memoryless broadcast
channels with confidential messages. Two private messages as well as a common
message are transmitted; the common message is to be decoded by both receivers,
while each private message is only for its intended receiver. In addition, each
private message is to be kept secret from the unintended receiver where secrecy
is measured by equivocation. We propose both inner and outer bounds to the rate
equivocation region for broadcast channels with confidential messages. The
proposed inner bound generalizes Csisz\'{a}r and K\"{o}rner's rate equivocation
region for broadcast channels with a single confidential message, Liu {\em et
al}'s achievable rate region for broadcast channels with perfect secrecy,
Marton's and Gel'fand and Pinsker's achievable rate region for general
broadcast channels. Our proposed outer bounds, together with the inner bound,
helps establish the rate equivocation region of several classes of discrete
memoryless broadcast channels with confidential messages, including less noisy,
deterministic, and semi-deterministic channels. Furthermore, specializing to
the general broadcast channel by removing the confidentiality constraint, our
proposed outer bounds reduce to new capacity outer bounds for the discrete
memory broadcast channel.Comment: 27 pages, 1 figure, submitted to IEEE Transaction on Information
Theor
MIMO Gaussian Broadcast Channels with Confidential and Common Messages
This paper considers the problem of secret communication over a two-receiver
multiple-input multiple-output (MIMO) Gaussian broadcast channel. The
transmitter has two independent, confidential messages and a common message.
Each of the confidential messages is intended for one of the receivers but
needs to be kept perfectly secret from the other, and the common message is
intended for both receivers. It is shown that a natural scheme that combines
secret dirty-paper coding with Gaussian superposition coding achieves the
secrecy capacity region. To prove this result, a channel-enhancement approach
and an extremal entropy inequality of Weingarten et al. are used.Comment: Submitted to 2010 IEEE International Symposium on Information Theory,
Austin, Texa
Secure Multiplex Coding with Dependent and Non-Uniform Multiple Messages
The secure multiplex coding (SMC) is a technique to remove rate loss in the
coding for wire-tap channels and broadcast channels with confidential messages
caused by the inclusion of random bits into transmitted signals. SMC replaces
the random bits by other meaningful secret messages, and a collection of secret
messages serves as the random bits to hide the rest of messages. In the
previous researches, multiple secret messages were assumed to have independent
and uniform distributions, which is difficult to be ensured in practice. We
remove this restrictive assumption by a generalization of the channel
resolvability technique.
We also give practical construction techniques for SMC by using an arbitrary
given error-correcting code as an ingredient, and channel-universal coding of
SMC. By using the same principle as the channel-universal SMC, we give coding
for the broadcast channel with confidential messages universal to both channel
and source distributions.Comment: We made several changes to improve the presentatio
New Results on Multiple-Input Multiple-Output Broadcast Channels with Confidential Messages
This paper presents two new results on multiple-input multiple-output (MIMO)
Gaussian broadcast channels with confidential messages. First, the problem of
the MIMO Gaussian wiretap channel is revisited. A matrix characterization of
the capacity-equivocation region is provided, which extends the previous result
on the secrecy capacity of the MIMO Gaussian wiretap channel to the general,
possibly imperfect secrecy setting. Next, the problem of MIMO Gaussian
broadcast channels with two receivers and three independent messages: a common
message intended for both receivers, and two confidential messages each
intended for one of the receivers but needing to be kept asymptotically
perfectly secret from the other, is considered. A precise characterization of
the capacity region is provided, generalizing the previous results which
considered only two out of three possible messages.Comment: Submitted to the IEEE Transactions on Information Theory, 11 pages, 5
figure
On the Compound MIMO Broadcast Channels with Confidential Messages
We study the compound multi-input multi-output (MIMO) broadcast channel with
confidential messages (BCC), where one transmitter sends a common message to
two receivers and two confidential messages respectively to each receiver. The
channel state may take one of a finite set of states, and the transmitter knows
the state set but does not know the realization of the state. We study
achievable rates with perfect secrecy in the high SNR regime by characterizing
an achievable secrecy degree of freedom (s.d.o.f.) region for two models, the
Gaussian MIMO-BCC and the ergodic fading multi-input single-output (MISO)-BCC
without a common message. We show that by exploiting an additional temporal
dimension due to state variation in the ergodic fading model, the achievable
s.d.o.f. region can be significantly improved compared to the Gaussian model
with a constant state, although at the price of a larger delay.Comment: To appear in Proc. IEEE Symposium on Information Theory (ISIT 2009)
June 28 - July 3, 2009, Seoul, Kore
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