Viterbi Decoder from LabVIEW RF Communications

[ArisEnding]

Hi guys~!

I am trying to develop a 32-bit Viterbi decoder. I am currently using the Viterbi decoder from the FPGA RF Communications Library available here. However, I can't seem to get it right. The 'decoded bit' output of the Viterbi decoder VI is always zero, no matter what the encoded symbol is. I put the VI inside a while loop while constantly inputting two-bit encoded input inside the VI. The VI I am using is posted in the picture and the project I developed is in the zip file! Many thanks!

[tannerite · Accepted solution]

Hi ArisEnding!

I have looked through the Viterbi Decoder example as well as your code and there seems to be discrepencies. It looks like you have removed the trellis information as well as the hamming information from the block diagram. I am not an expert with the Viterbi Decoder algorithm but these seem to be needed by the algorithm. It does look like you modified this on purpose. If you are looking for others with a more intimate knowledge of the Viterbi Decoder algorithm, I would recommend posting to the Viterbi Decoder example community page.

Best,

-tannerite

[ArisEnding]

Hi! Thank you very much for your reply. Actually, I already figured out the problem. I did try to tinker with the subVIs in the Viterbi Decoder VI and changed the traceback lengths. There were some discrepancies since I changed some from 40 to 35 but forgot to change some of them. Moreover, for my 32-bit input to the decoder, the error rate decreased when I input two flush bits at the beginning.

Thank you very much for your help!

[tannerite]

ArisEnding,

Awesome! I am glad you got to the bottom of it!

[rc_cks]

I am trying to build these VI's, finding hard time.. Can you please upload your Viterbi Decoder and Hamming Decoder VI. THanks for your help, 

[Danny_Kaps]

Hello rc_cks,

As this is a long-resolved post from a few years ago, I think you would have greater success getting visibility with a new post on the LabVIEW Communications forum, here: http://forums.ni.com/t5/LabVIEW-Communications-System/bd-p/540

I would make sure to reference this forum post, as well as provide as much detail on your project as possible. The community may have new or improved solutions for your application's challenges!

Best,

Daniel 

[rc_cks]

Thank you so much for your reply. I do not see any link that refers to Viterbi Decoder VI. I am trying hard, but not able to resolve it. Still trying to understand the concept.

Can you please share the source code for Viterbi decoder. Unfortunately, I do not have  much time to accomplish this, Coz this project is due tommorrow (Given only 48 hrs time by prof 😞 ) .  

Would it be possible for you o share the VI's now ? 

[Danny_Kaps]

Hello rc_cks,

All the code discussed here was developed by and for the community, I do not have access to any separate internal source code. It looks like the RF Communications Library and Generic Viterbi Decoder are located here:

http://forums.ni.com/t5/Example-Program-Drafts/Viterbi-Decoder/ta-p/3494158

There is another Viterbi example here: http://forums.ni.com/t5/Community-Documents/Examples-using-LabVIEW-FPGA-RF-Communications-Library-3-...

If this is not what you are looking for, a new forum post is more likely to be seen by the community than this older one!

Best,

Daniel