Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pilot Power Allocation Through User Grouping in Multi-Cell Massive MIMO
  Systems   In this paper, we propose a relative channel estimation error (RCEE) metric,
and derive closed-form expressions for its expectation $\rm {Exp}_{rcee}$ and
the achievable uplink rate holding for any number of base station antennas $M$,
with the least squares (LS) and minimum mean squared error (MMSE) estimation
methods. It is found that RCEE and $\rm {Exp}_{rcee}$ converge to the same
constant value when $M\rightarrow\infty$, resulting in the pilot power
allocation (PPA) is substantially simplified and a PPA algorithm is proposed to
minimize the average $\rm {Exp}_{rcee}$ per user with a total pilot power
budget $P$ in multi-cell massive multiple-input multiple-output systems.
Numerical results show that the PPA algorithm brings considerable gains for the
LS estimation compared with equal PPA (EPPA), while the gains are only
significant with large frequency reuse factor (FRF) for the MMSE estimation.
Moreover, for large FRF and large $P$, the performance of the LS approaches to
the performance of the MMSE, which means that simple LS estimation method is a
very viable when co-channel interference is small. For the achievable uplink
rate, the PPA scheme delivers almost the same average achievable uplink rate
and improves the minimum achievable uplink rate compared with the EPPA scheme.

21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas