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Lcrypto / EMS-decoder-of-NB-LDPC-codes

Extended Min-Sum decoder of NB-LDPC codes. Complexity reduction of MS using truncated low values LLRs
BSD 2-Clause "Simplified" License
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Whether this decoder supports NB-LDPC codes over GF(32) ? #1

Open Liubusy opened 8 months ago

Liubusy commented 8 months ago

Hi, I am very interested in the EMS algorithm for NB-LDPC codes. I have tried to use the NB_LDPC_FB decoder to decode the regular (837, 726) NB-LDPC code over GF(32) . However, there is about 0.5 dB coding gain loss at the BER of 10-4. Does it need some mofications to adapt to the regular (837, 726) NB-LDPC code over GF(32)? If yes, could you tell us where should be modifed? Thank you so much！ I am looking forward to hearing from you.

Lcrypto commented 8 months ago

On what modulation? Better to check GF(q)-> QAM(q) to have better performance except odd degrees in QAM because for example QAM32, QAM128 always lose due to corner points of the constellation. Most gain for NB get from shapping gain

Liubusy commented 8 months ago

Thank you for your reply. The modulation is BPSK.

Lcrypto commented 8 months ago

You are Welcome! NB-LDPC compare to carefull design binary LDPC (trapping sets optimized) doesn't snow large gain, for large protograph < 0.15 dB. Most gain going from constelattion shapping (mapping GF(q) symbols to q constelation) under Bandwidth limited regime but for such cases you can use probability shapping + binary LDPC.