Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Capacity Achieving Modulation for Fixed Constellations with Average
  Power Constraint   The capacity achieving probability mass function (PMF) of a finite signal
constellation with an average power constraint is in most cases non-uniform. A
common approach to generate non-uniform input PMFs is Huffman shaping, which
consists of first approximating the capacity achieving PMF by a sampled
Gaussian density and then to calculate the Huffman code of the sampled Gaussian
density. The Huffman code is then used as a prefix-free modulation code. This
approach showed good results in practice, can however lead to a significant gap
to capacity. In this work, a method is proposed that efficiently constructs
optimal prefix-free modulation codes for any finite signal constellation with
average power constraint in additive noise. The proposed codes operate as close
to capacity as desired. The major part of this work elaborates an analytical
proof of this property. The proposed method is applied to 64-QAM in AWGN and
numeric results are given, which show that, opposed to Huffman shaping, by
using the proposed method, it is possible to operate very close to capacity
over the whole range of parameters.

37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg