Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Concurrent Channel Probing and Data Transmission in Full-duplex MIMO
  Systems   An essential step for achieving multiplexing gain in MIMO downlink systems is
to collect accurate channel state information (CSI) from the users.
Traditionally, CSIs have to be collected before any data can be transmitted.
Such a sequential scheme incurs a large feedback overhead, which substantially
limits the multiplexing gain especially in a network with a large number of
users. In this paper, we propose a novel approach to mitigate the feedback
overhead by leveraging the recently developed Full-duplex radios. Our approach
is based on the key observation that using Full-duplex radios, when the
base-station (BS) is collecting CSI of one user through the uplink channel, it
can use the downlink channel to simultaneously transmit data to other
(non-interfering) users for which CSIs are already known. By allowing
concurrent channel probing and data transmission, our scheme can potentially
achieve a higher throughput compared to traditional schemes using Half-duplex
radios. The new flexibility introduced by our scheme, however, also leads to
fundamental challenges in achieving throughout optimal scheduling. In this
paper, we make an initial effort to this important problem by considering a
simplified group interference model. We develop a throughput optimal scheduling
policy with complexity $O((N/I)^I)$, where $N$ is the number of users and $I$
is the number of user groups. To further reduce the complexity, we propose a
greedy policy with complexity $O(N\log N)$ that not only achieves at least 2/3
of the optimal throughput region, but also outperforms any feasible Half-duplex
solutions. We derive the throughput gain offered by Full-duplex under different
system parameters and show the advantage of our algorithms through numerical
studies.

30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg