Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Physical Layer Security Enhancement Exploiting Intelligent Reflecting
  Surface   In this letter, the use of intelligent reflecting surface (IRS) to enhance
the physical layer security of downlink wireless communication is investigated.
Assuming a single-antenna legitimate user and a multi-antenna eavesdropper, we
propose an effective algorithm to jointly optimize the active and passive
beamforming. In the proposed algorithm, the optimal transmit beamforming vector
at the BS under fixed IRS phase shifts is derived, and a low-complexity
algorithm based on fractional programming (FP) and manifold optimization (MO)
is proposed to obtain near optimal IRS phase shifts. Simulation results
demonstrate that the proposed algorithm can almost achieve the performance
upper bound with a fast convergence rate.

14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th