Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Random Access in Uplink Massive MIMO Systems: How to exploit
  asynchronicity and excess antennas   Massive MIMO systems, where the base stations are equipped with hundreds of
antennas, are an attractive way to handle the rapid growth of data traffic. As
the number of users increases, the initial access and handover in contemporary
networks will be flooded by user collisions. In this work, we propose a random
access procedure that resolves collisions and also performs timing, channel,
and power estimation by simply utilizing the large number of antennas
envisioned in massive MIMO systems and the inherent timing misalignments of
uplink signals during network access and handover. Numerical results are used
to validate the performance of the proposed solution under different settings.
It turns out that the proposed solution can detect all collisions with a
probability higher than 90%, at the same time providing reliable timing and
channel estimates. Moreover, numerical results demonstrate that it is robust to
overloaded situations.

25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph