Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Joint Beamforming and Broadcasting in Massive MIMO   The downlink of a massive MIMO system is considered for the case in which the
base station must concurrently serve two categories of terminals: one group to
which imperfect instantaneous channel state information (CSI) is available, and
one group to which no CSI is available. Motivating applications include
broadcasting of public channels and control information in wireless networks.
  A new technique is developed and analyzed: joint beamforming and broadcasting
(JBB), by which the base station beamforms to the group of terminals to which
CSI is available, and broadcasts to the other group of terminals, to which no
CSI is available. The broadcast information does not interfere with the
beamforming as it is placed in the nullspace of the channel matrix collectively
seen by the terminals targeted by the beamforming. JBB is compared to
orthogonal access (OA), by which the base station partitions the time-frequency
resources into two disjunct parts, one for each group of terminals.
  It is shown that JBB can substantially outperform OA in terms of required
total radiated power for given rate targets.

11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph