4.2. LDPC IP Core Parameters
Parameter | Value | Description |
---|---|---|
Standard | DVB-S2 NASA GSFC-STD-9100 WiMedia 1.5 DOCSIS 3.1 WiFi 802.11n |
Type of LDPC code. |
LDPC module | Encoder or decoder | NASA GSFC-STD-9100, WiMedia 1.5, DOCSIS 3.1, and Wifi 802.11n only. |
Codeword length | Encoder DVB-S2: 16200, 64800 Decoder:
|
Number of bits per codeword. |
Coding rate | DVB:S2: 1/4 1/3 2/5 1/2 3/5 2/3 3/4 4/5 5/6 8/9 DOCSIS 3.1: 75% 85% 89% NASA GSFC-STD-9100: 7/8 WiMedia 1.5: 0.5, 0.625, 0.75, 0.8 |
- |
Number of bits per input symbol | 1 to 30 | Encoder only. |
Number of LLRs per input symbol | 2 to 40 (NASA, DOCSIS, and WiMedia) | The number of LLRs you feed in parallel to the decoder |
Number of softbits per input LLR | 2 to 16 | Decoder only. The width of the input LLR. Assume that the number of bits per output symbol is equal the number of LLR per input symbol |
Parameter | Value | Description |
---|---|---|
Number of decoding iterations | 1 to 100 | The maximum number of decoding iterations. A decoding iteration corresponds to the decoding of all the rows of the parity-check matrix. The decoder stops decoding once it finds a valid codeword. |
Parallelism | 1 to 100 | The number of rows processed in parallel during the decoding. |
Width of the decoder variables | 4 or 16 | The width of the input LLR. The decoder can represent the LLR it processes by a much larger number of softbits than the input LLRs. |
MSA attenuation factor | 1, 0.875, 0.75, 0.625, 0.5, 0.375, 0.25 | The design applies a constant attenuation factor to the output of the min-sum algorithm (MSA) processing to ease convergence. This factor is a sum of inverse of power of 2. |
Full-streaming architecture | No or yes | With full streaming architecture, the decoder can accept data while decoding if the level of parallelization is sufficient. NASA only. |
Layered decoding | No or yes | NASA GSFC-STD-9100 decoder only |
Output parity check bits | No or yes | Decoder provides output parity check bits or information bits only. |