Ldpc Encoding; Table 25: Ldpc Code - Safran CORTEX CRT Quantum User Manual

1.1.1.1.1

LDPC Encoding

This processing provides the capabilities corresponding to the encoding recommended in § 5 of CCSDS 131.0-
B-3. The corresponding decoding is license dependent.
The LDPC-encoding is available in the File, Pseudo and BERT File operating modes.
It is activated by programming the parameter Frame Encoding to LDPC-code. The frames are generated by
using the parameters Frame Length and LDPC Code Rate of the TMU associated owing to the parameter TM
Flow for BER/Encoding. In the particular case of LDPC decoding, the TMU Frame Length has to be configured
with the uncoded information block length,
the TMU LDPC Code Rate.
Information
Block Length
bits [bytes]
Code rate
1024 [128]
4096 [512]
16384 [2048]
7136 [892]
sync. marker length
In Pseudo mode, the Frame Length of the associated TMU must be configured with the information block length
expressed in bits. The length of (sync. Marker + LDPC code block) is given by the formula:
where �� is the code rate and �� the information block length in bits.
In File mode, the information data blocks (and only them) have to be provided in the selected file. Moreover, it is
possible to repeat the encoding of several consecutive blocks. In this case, the TMS Format Length has to
match the several frames which have to be encoded, and so to be configured to the value corresponding to the
TMU Frame Length times the number of encoded blocks (Hence, in this case, the TMS format length is
expressed in bits too). In this case the data shall be organized in the file according to the following structure:
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CRT QUANTUM USER'S MANUAL
expressed in
1/2
2048 [256]
8192 [1024]
32768 [4096]
64
Table 25: LDPC code : information block and codeblock lengths
����������ℎ = ( �������� ������������ ) + �� �� ⁄
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bits. The Sync. Marker is automatically deduced from
Code Block Length
bits [bytes]
2/3
1536 [192] 1280 [160]
6144 [768] 5120 [640]
24576 [3072] 20480 [2560]
64
Safran Data Systems
.
Ref. DTU 100042
Is.Rev. 5.17
Date: Dec.
03, 2021Sept. 30, 2021
4/5 7/8
8160 [1020]
64 32
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