Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Uplink Downlink Rate Balancing and throughput scaling in FDD Massive
  MIMO Systems   In this work we extend the concept of uplink-downlink rate balancing to
frequency division duplex (FDD) massive MIMO systems. We consider a base
station with large number antennas serving many single antenna users. We first
show that any unused capacity in the uplink can be traded off for higher
throughput in the downlink in a system that uses either dirty paper (DP) coding
or linear zero-forcing (ZF) precoding. We then also study the scaling of the
system throughput with the number of antennas in cases of linear Beamforming
(BF) Precoding, ZF Precoding, and DP coding. We show that the downlink
throughput is proportional to the logarithm of the number of antennas. While,
this logarithmic scaling is lower than the linear scaling of the rate in the
uplink, it can still bring significant throughput gains. For example, we
demonstrate through analysis and simulation that increasing the number of
antennas from 4 to 128 will increase the throughput by more than a factor of 5.
We also show that a logarithmic scaling of downlink throughput as a function of
the number of receive antennas can be achieved even when the number of transmit
antennas only increases logarithmically with the number of receive antennas.

22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph