Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constant Envelope Precoding for MIMO Systems   Constant envelope (CE) precoding is an appealing transmission technique,
which enables highly efficient power amplification, and is realizable with a
single radio frequency (RF) chain at the multi-antenna transmitter. In this
paper, we study the transceiver design for a point-to-point multiple-input
multiple-output (MIMO) system with CE precoding. Both single-stream
transmission (i.e., beamforming) and multi-stream transmission (i.e., spatial
multiplexing) are considered. For single-stream transmission, we optimize the
receive beamforming vector to minimize the symbol error rate (SER) for any
given channel realization and desired constellation at the combiner output. By
reformulating the problem as an equivalent quadratically constrained quadratic
program (QCQP), we propose an efficient semi-definite relaxation (SDR) based
algorithm to find an approximate solution. Next, for multi-stream transmission,
we propose a new scheme based on antenna grouping at the transmitter and
minimum mean squared error (MMSE) or zero-forcing (ZF) based beamforming at the
receiver. The transmit antenna grouping and receive beamforming vectors are
then jointly designed to minimize the maximum SER over all data streams.
Finally, the error-rate performance of single- versus multi-stream transmission
is compared via simulations under different setups.

19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin