EXITCallback

class sionna.phy.fec.ldpc.EXITCallback(num_iter: int, device: str | None = None)

Bases: sionna.phy.object.Object

Callback for the LDPCBPDecoder to track EXIT statistics.

Can be registered as c2v_callbacks or v2c_callbacks in the LDPCBPDecoder and the LDPC5GDecoder.

This callback requires all-zero codeword simulations.

Parameters:

• num_iter (int) – Maximum number of decoding iterations.

• device (str | None) – Device for computation (e.g., ‘cpu’, ‘cuda:0’).

Inputs:

• msg – [batch_size, num_vns, max_degree], torch.float. The v2c or c2v messages.

• it – int. Current number of decoding iterations.

Outputs:

msg – torch.float. Same as msg.

Examples

from sionna.phy.fec.ldpc import LDPCBPDecoder
from sionna.phy.fec.ldpc.utils import EXITCallback

# Create callback
exit_cb = EXITCallback(num_iter=20)

# Create decoder with callback
decoder = LDPCBPDecoder(pcm, v2c_callbacks=[exit_cb])

# After decoding, access mutual information
mi = exit_cb.mi

Attributes

property mi: torch.Tensor

Mutual information after each iteration