Dynamic Layered Decoding Scheduling for LDPC Codes Aided by Check Node Unsatisfied Probabilities

This letter revisits update ordering in layered belief propagation (LBP) decoding of low-density parity-check (LDPC) codes.

The closest probability-based schedule orders layers by check node unsatisfied probabilities estimated only from the channel observations, although these probabilities change once decoding messages are exchanged.

We therefore refresh the check node unsatisfied probabilities during decoding and use them as dynamic priorities.

The first schedule, Dyn-EBP, selects the most reliable available check node while ensuring that every check node is updated once in each iteration.

The second schedule, Dyn-PEBP, adds a linear update-count penalty and allows limited repeated updates without letting a small subset of check nodes dominate the schedule.

For 5G new radio LDPC base graph 1 codes with five iterations, the proposed schedules yield small BLER reductions relative to the channel-only probability schedule and remain competitive with LBP, LPHD scheduling, and RD-RBP.

The gain is modest, but it shows that probability-based scheduling benefits from message-level refinement.