Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Secrecy Capacity of a MIMO Gaussian Wiretap Channel with a
  Cooperative Jammer   We study the secrecy capacity of a helper-assisted Gaussian wiretap channel
with a source, a legitimate receiver, an eavesdropper and an external helper,
where each terminal is equipped with multiple antennas. Determining the secrecy
capacity in this scenario generally requires solving a nonconvex secrecy rate
maximization (SRM) problem. To deal with this issue, we first reformulate the
original SRM problem into a sequence of convex subproblems. For the special
case of single-antenna legitimate receiver, we obtain the secrecy capacity via
a combination of convex optimization and one-dimensional search, while for the
general case of multi-antenna legitimate receiver, we propose an iterative
solution. To gain more insight into how the secrecy capacity of a
helper-assisted Gaussian wiretap channel behaves, we examine the achievable
secure degrees of freedom (s.d.o.f.) and obtain the maximal achievable s.d.o.f.
in closed-form. We also derive a closed-form solution to the original SRM
problem which achieves the maximal s.d.o.f.. Numerical results are presented to
illustrate the efficacy of the proposed schemes.

12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol