Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On-the-fly Uplink Training and Pilot Code Sequence Design for Cellular
  Networks   Cellular networks of massive MIMO base-stations employing TDD/OFDM and
relying on uplink training for both downlink and uplink transmission are viewed
as an attractive candidate for 5G deployments, as they promise high area
spectral and energy efficiencies with relatively simple low-latency operation.
We investigate the use of non-orthogonal uplink pilot designs as a means for
improving the area spectral efficiency in the downlink of such massive MIMO
cellular networks. We develop a class of pilot designs that are locally
orthogonal within each cell, while maintaining low inner-product properties
between codes in different cells. Using channel estimates provided by
observations on these codes, each cell independently serves its locally active
users with MU-MIMO transmission that is also designed to mitigate interference
to a subset of `strongly interfered' out-of-cell users. As our simulation-based
analysis shows, such cellular operation based on the proposed codes yields
user-rate CDF improvement with respect to conventional operation, which can be
exploited to improve cell and/or cell-throughput performance.

33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th