Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Secrecy Degrees of Freedom of Multi-Antenna Wiretap Channels with
  Delayed CSIT   The secrecy degrees of freedom (SDoF) of the Gaussian multiple-input and
single-output (MISO) wiretap channel is studied under the assumption that
delayed channel state information (CSI) is available at the transmitter and
each receiver knows its own instantaneous channel. We first show that a
strictly positive SDoF can be guaranteed whenever the transmitter has delayed
CSI (either on the legitimate channel or/and the eavesdropper channel). In
particular, in the case with delayed CSI on both channels, it is shown that the
optimal SDoF is 2/3. We then generalize the result to the two-user Gaussian
MISO broadcast channel with confidential messages and characterize the SDoF
region when the transmitter has delayed CSI of both receivers. Interestingly,
the artificial noise schemes exploiting several time instances are shown to
provide the optimal SDoF region by masking the confidential message to the
unintended receiver while aligning the interference at each receiver.

34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th