22 research outputs found
On Secure Transmission over Parallel Relay Eavesdropper Channel
We study a four terminal parallel relay-eavesdropper channel which consists
of multiple independent relay-eavesdropper channels as subchannels. For the
discrete memoryless case, we establish inner and outer bounds on the
rate-equivocation region. For each subchannel, secure transmission is obtained
through one of the two coding schemes at the relay: decoding-and-forwarding the
source message or confusing the eavesdropper through noise injection. The inner
bound allows relay mode selection. For the Gaussian model we establish lower
and upper bounds on the perfect secrecy rate. We show that the bounds meet in
some special cases, including when the relay does not hear the source. We
illustrate the analytical results through some numerical examples.Comment: 8 pages, Presented at the Forty-Eighth Annual Allerton Conference on
Communication, Control, and Computing, September 29 - October 1, 2010,
Monticello, IL, US
On SDoF of Multi-Receiver Wiretap Channel With Alternating CSIT
We study the problem of secure transmission over a Gaussian multi-input
single-output (MISO) two receiver channel with an external eavesdropper, under
the assumption that the state of the channel which is available to each
receiver is conveyed either perfectly () or with delay () to the
transmitter. Denoting by , , and the channel state information
at the transmitter (CSIT) of user 1, user 2, and eavesdropper, respectively,
the overall CSIT can then alternate between eight possible states, i.e.,
. We denote by the
fraction of time during which the state occurs. Under these
assumptions, we first consider the Gaussian MISO wiretap channel and
characterize the secure degrees of freedom (SDoF). Next, we consider the
general multi-receiver setup and characterize the SDoF region of fixed hybrid
states , , and . We then focus our attention on the symmetric
case in which . For this case, we establish bounds
on SDoF region. The analysis reveals that alternating CSIT allows synergistic
gains in terms of SDoF; and shows that, by opposition to encoding separately
over different states, joint encoding across the states enables strictly better
secure rates. Furthermore, we specialize our results for the two receivers
channel with an external eavesdropper to the two-user broadcast channel. We
show that, the synergistic gains in terms of SDoF by alternating CSIT is not
restricted to multi-receiver wiretap channels; and, can also be harnessed under
broadcast setting.Comment: To Appear in IEEE Transactions on Information Forensics and Securit
Secure Communication over Parallel Relay Channel
We investigate the problem of secure communication over parallel relay
channel in the presence of a passive eavesdropper. We consider a four terminal
relay-eavesdropper channel which consists of multiple relay-eavesdropper
channels as subchannels. For the discrete memoryless model, we establish outer
and inner bounds on the rate-equivocation region. The inner bound allows mode
selection at the relay. For each subchannel, secure transmission is obtained
through one of two coding schemes at the relay: decoding-and-forwarding the
source message or confusing the eavesdropper through noise injection. For the
Gaussian memoryless channel, we establish lower and upper bounds on the perfect
secrecy rate. Furthermore, we study a special case in which the relay does not
hear the source and show that under certain conditions the lower and upper
bounds coincide. The results established for the parallel Gaussian
relay-eavesdropper channel are then applied to study the fading
relay-eavesdropper channel. Analytical results are illustrated through some
numerical examples.Comment: To Appear in IEEE Transactions on Information Forensics and Securit
Secure Degrees of Freedom of MIMO X-Channels with Output Feedback and Delayed CSIT
We investigate the problem of secure transmission over a two-user multi-input
multi-output (MIMO) X-channel in which channel state information is provided
with one-unit delay to both transmitters (CSIT), and each receiver feeds back
its channel output to a different transmitter. We refer to this model as MIMO
X-channel with asymmetric output feedback and delayed CSIT. The transmitters
are equipped with M-antennas each, and the receivers are equipped with
N-antennas each. For this model, accounting for both messages at each receiver,
we characterize the optimal sum secure degrees of freedom (SDoF) region. We
show that, in presence of asymmetric output feedback and delayed CSIT, the sum
SDoF region of the MIMO X-channel is same as the SDoF region of a two-user MIMO
BC with 2M-antennas at the transmitter, N-antennas at each receiver and delayed
CSIT. This result shows that, upon availability of asymmetric output feedback
and delayed CSIT, there is no performance loss in terms of sum SDoF due to the
distributed nature of the transmitters. Next, we show that this result also
holds if only output feedback is conveyed to the transmitters, but in a
symmetric manner, i.e., each receiver feeds back its output to both
transmitters and no CSIT. We also study the case in which only asymmetric
output feedback is provided to the transmitters, i.e., without CSIT, and derive
a lower bound on the sum SDoF for this model. Furthermore, we specialize our
results to the case in which there are no security constraints. In particular,
similar to the setting with security constraints, we show that the optimal sum
DoF region of the (M,M,N,N)--MIMO X-channel with asymmetric output feedback and
delayed CSIT is same as the DoF region of a two-user MIMO BC with 2M-antennas
at the transmitter, N-antennas at each receiver, and delayed CSIT. We
illustrate our results with some numerical examples.Comment: To Appear in IEEE Transactions on Information Forensics and Securit
Trackable CEMB-Klean Cotton Transgenic Technology: Affordable Climate Neutral Agri-biotech Industrialization for Developing Countries
Background: Transgenic technology reflects the incorporation of novel useful traits in crop plants like cotton for economic benefits by overcoming the problems including insectsâ pests and weeds in special. The present study is the success story of the continuous effort of CEMB team started back in the 1990s.Methods: This study includes characterization of a large number of Bacillus thuringiensis (Bt) strains taken from local soil and subjected to direct transformation of isolated BT genes into local cotton cultivars. Protocols for transformation into cotton plants were optimized and validated by the development of double gene codon optimized (Cry1Ac and Cry2A) transgenic cotton varieties.Results: The resulting GMOs in the form of CEMB-33, CA-12, CEMB-66 have been approved by Punjab Seed Council in 2013 and 2016 respectively. Double Bt and weedicide resistant cotton harboring CEMB-Modified and codon optimized cp4EPSPS (GTGene). These varieties can tolerate glyphosate spray @ 1900ml per acre without the appearance of necrotic spots/shedding and complete removal of all surrounding weeds in the cotton field is a significant advance to boost cotton production without spending much on insecticides and herbicides.Conclusion: In the current report, two unique sets of primers which amplify 1.1 Kb for CEMB-double Bt genes and 660 bp product for CEMB-Modified cp4EPSPS (GTGene) were tested. CEMB cotton variety CKC-01 is specially designed as low cost and easy to use by local farmerâs technology has the potential to revolutionize the cotton growing culture of the country.Keywords: Event detection; Bt Cotton; CEMB transgenic technology; GTGen
On physical layer security in cooperative networks
With the advent of mobile telephony, complemented by the availability of economic infrastructure devices has provided users the freedom to communicate and perform everyday tasks wirelessly. The access to information anywhere anytime provide users more flexibility to communicate, nonetheless it also makes communication more vulnerable to eavesdropping. Security is now considered as an important issue in the design of modern wireless communication system. In contrast to the conventional systems where security issues are dealt in the upper
layers of the protocol stack, in this thesis we focus our attention to construct security schemes by exploiting the attributes of the physical layer.
In the first part of the thesis, we consider a two-user multiacces channel where the two encoders, Encoder 1 and Encoder 2, are allowed to communicate with each other over a unidirectional noiseless bit-pipe of finite capacity in the presence of an adversary. In this model, the role of Encoder 2 is restricted to only help Encoder 1 in securing information from adversary. For this model, we
establish fundamental performance limits on secure communication and characterizes the secrecy capacity in some extreme cases of cooperation between the encoders. The second part of the thesis considers an elementary
network, which consists of four nodes â a source, a relay, a legitimate receiver and a passive eavesdropper. In this network, the link between two nodes consists of multiple parallel channels as subchannel. Towards this end, we establish bounds on secure communication. We show that for the case in which the relay does not listens to the source, under certain conditions secrecy capacity is established. In the last part of the thesis, we studied a two-user multi-input multioutput X-channel with local feedback and delayed channel state information
available at the transmitter in high signal-to-noise ratio regimes. In this setting each transmitter transmits independent messages to both receivers that need to be kept secret from each other. We characterize the optimal sum secure degrees of freedom region of this model.(FSA 3) -- UCL, 201