3.2.4.4.1. Polar Encoder parameters

3.2.4.4.1.1. --enc-type

Type

text

Allowed values

POLAR AZCW COSET USER

Default

POLAR

Examples

--enc-type AZCW

Select the encoder type.

Description of the allowed values:

Value	Description
POLAR	Select the standard Polar encoder.
AZCW	See the common --enc-type parameter.
COSET	See the common --enc-type parameter.
USER	See the common --enc-type parameter.

3.2.4.4.1.2. --enc-no-sys

Enable non-systematic encoding. By default the encoding process is systematic.

3.2.4.4.1.3. --enc-fb-gen-method

Type

text

Allowed values

FILE GA TV BEC 5G

Examples

--enc-fb-gen-method FILE

Select the frozen bits generation method.

Description of the allowed values:

Value	Description
GA	Select the GA method from [Plre-Tri12].
TV	Select the TV method which is based on Density Evolution (DE) approach from [Plre-TV13], to use with the --enc-fb-awgn-path parameter.
FILE	Read the best channels from an external file, to use with the --enc-fb-awgn-path parameter.
BEC	Generate frozen bits for the BEC channel from [Plrd-Ari09].
5G	Generate the frozen bits as described in the 5G standard [Plre-3GPP].

Note

By default, when using the GA or the TV method, the frozen bits are optimized for each SNR point. To override this behavior you can use the --enc-fb-noise parameter.

Note

When using the FILE method, the frozen bits are always the same regardless of the SNR value.

Note

When using the BEC method, the frozen bits are optimized for each erasure probability.

Note

When using the 5G method, the codeword size must be inferior to 1024.

3.2.4.4.1.4. --enc-fb-awgn-path

Type

path

Rights

read only

Examples

--enc-fb-awgn-path example/path/to/the/right/place/

Set the path to a file or a directory containing the best channels to select the frozen bits.

An ASCII file is expected, for instance, the following file describes the most reliable channels optimized for a codeword of size \(N = 8\) and for an AWGN channel where the noise variance is \(\sigma = 0.435999\):

8
awgn
0.435999
7 6 5 3 4 2 1 0

Given the previous file, if we suppose a Polar code of size \(N = 8\) with \(K = 4\) information bits, the frozen bits are at the 0, 1, 2, 4 positions in the codeword. The strategy is to freeze the less reliable channels.

Warning

The FILE frozen bits generator expects a file and not a directory.

Warning

The TV frozen bits generator expects a directory and not a file. AFF3CT comes with input configuration files, a part of those configuration files are a set of best channels pre-generated with the TV method (see conf/cde/awgn_polar_codes/TV/).

3.2.4.4.1.5. --enc-fb-dump-path

Type

folder

Rights

write only

Examples

--enc-fb-dump-path example/path/to/the/right/place/

Set the path to store the best channels.

Note

Works only for the GA and BEC frozen bits generation methods.

3.2.4.4.1.6. --enc-fb-noise

Type

real number

Examples

--enc-fb-noise 1.0

Select the noise for which the frozen bits will be optimized.

Can be a gaussian noise variance \(\sigma\) for GA and TV generation methods, or an event probability for the BEC generation method. All the noise points in the simulation will use the same frozen bits configuration.

3.2.4.4.1.7. References

Plre-TV13

I. Tal and A. Vardy. How to construct polar codes. IEEE Transactions on Information Theory (TIT), 59(10):6562–6582, October 2013. doi:10.1109/TIT.2013.2272694.

Plre-Tri12

P. Trifonov. Efficient design and decoding of polar codes. IEEE Transactions on Communications (TCOM), 60(11):3221–3227, November 2012. doi:10.1109/TCOMM.2012.081512.110872.

Plre-3GPP

3GPP. TS 38.212, Multiplexing and Channel Coding (Release 15). URL: http://www.3gpp.org/ftp//Specs/archive/38_series/38.212/.