Linked-loop Code

This is the codebase to the papers: "Coding for the unsourced A-channel with erasures: the linked loop code" (https://ieeexplore.ieee.org/abstract/document/10289955, EUSIPCO 2023) and "Coding for the Unsourced B-Channel with Erasures: Enhancing the Linked Loop Code" (https://ieeexplore.ieee.org/abstract/document/10445848, ICASSP 2024).

Where to run the codes?

To start a simulation, please use go to the Develop branch, and the folder playground, then use the command python simple_launcher.py --Ka=100 --pe=0.05 --L=16 --sic=1 --M=2 --ctype=B to launch a simulation. The name of the parameters should be self-explanatory.

• K (>1) denotes the number of active users.
• pe (positive number between [0,1]) denotes the erasure probability, when $$p_e=0$$ the channel is clean, and when $$p_e=1$$ the channel is erasing everything.
• L (15 or 16)denotes the number of sections.
• sic (0 or 1) indicates whether to apply successive interference cancallation.
• M (2 or 3) denotes the window size -- how many previous sections a parity portion of any section should base on.
• ctype ("A" or "B") determines the channel type, deciding whether to simulate on A-channel or B-channel.

How to read the results?

Some result like the following is expected to appear, where we applied a 3-phased recovery step. In specific, this demostration result says we managed to recover 92 true positives out of 100 transmitted messages. And 1 false alarm (in this simulation).

• Phase 1 try to find ALL parity consistent paths that suffers NO erasures.
• Phase 2 try to find ALL (the remaining) parity consistent paths that suffers 1 erasures.
• Phase 3 try to find SOME (the remaining) parity consistent paths that suffers 2 (E.g., not happening in consecutive sections) erasures.
• For phase 2.xxx, 3.xxx, these mean we are operating the "multiple root" method. We occasionally change the root section to see if we can decode more messages at the current phase.

####### Start Rocking ######## K=100 and p_e= 0.05 and L= 16 and M= 2 and ctype: B
 -- Decoding phase 1 now starts.
 99%|██████████████████████████████████████████████| 95/96 [00:02<00:00, 37.04it/s]
 | Time of phase 1 (LLC): 2.573298931121826
 | In phase 1 linked loop Code decodes 42 true message out of 42
 -Phase 1 Done.

 -- Decoding phase 2 now starts.
 98%|█████████████████████████████████████████████| 53/54 [00:29<00:00,  1.81it/s]
 | Time of phase 2.1 29.349550008773804
 | In phase 2.1 Linked-loop Code decodes 35 true message out of 35
 95%|████████████████████████████████████████████| 19/20 [00:00<00:00, 42.04it/s]
 | Time of phase 2.2 0.4530029296875
 | In phase 2.2 Linked-loop Code decodes 1 true message out of 1
 | In phase up-to-phase 2 Linked-loop Code decodes 78 true message out of 78
 -Phase 2 is done. 

 -- Decoding phase 3 now starts.
 95%|████████████████████████████████████████████ | 18/19 [00:15<00:00,  1.14it/s]
 | Time of phase 3.1 15.845634698867798
 | In phase 3.1 Linked-loop Code decodes 12 true message out of 13
 88%|███████████████████████████████████████████ | 7/8 [00:02<00:00,  2.35it/s]
 | Time of phase 3.2 2.9842469692230225
 | In phase 3.2 Linked-loop Code decodes 2 true message out of 2
 80%|████████████████████████████████████████████| 4/5 [00:00<00:00, 109.37it/s]
 | Time of phase 3.3 0.03735232353210449
 | In phase up-to-phase 3 Linked-loop Code decodes 92 true message out of 93
 -Phase 3 is done, this simulation terminates.