LDPC Noise Channels

The channel types record the parameters of the standard binary-input channels and provide their capacities and log-likelihood ratios. transmit draws a channel realization, which is the input the soft-decision decoders expect.

The LDPC ensemble types also live in this file group: an LDPCEnsemble is described by its degree distributions rather than by a specific matrix, and a METEnsemble is the multi-edge-type generalization, where edges are sorted into classes so that different sockets of a variable node can attach to different classes of check node. The analysis routines that consume them are in Analysis.

CodingTheory.llr — Method
llr(
    Ch::BinaryErasureChannel,
    y::AbstractVector{Int64}
) -> Any

Convert a received channel sequence y into Log-Likelihood Ratios (LLRs).

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CodingTheory.llr — Method
llr(
    Ch::RayleighFadingChannel,
    received::Tuple{Vector{Float64}, Vector{Float64}}
) -> Vector{Float64}

Return the exact log-likelihood ratios (LLRs) for a received Rayleigh fading signal, where received is the tuple (y, a) returned by transmit.

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CodingTheory.llr — Method
llr(
    Ch::ZChannel,
    received::Vector{Int64}
) -> Vector{Float64}

Return the exact log-likelihood ratios (LLRs) for a received Z-channel signal.

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CodingTheory.transmit — Method
transmit(
    Ch::BinaryErasureChannel,
    x::AbstractVector{Int64}
) -> Any

Transmit a binary vector x through the channel, returning the corrupted vector y.

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CodingTheory.transmit — Method
transmit(
    Ch::RayleighFadingChannel,
    codeword::Vector{Int64}
) -> Tuple{Vector{Float64}, Vector{Float64}}

Simulate transmitting a binary codeword over a Rayleigh Fading Channel using BPSK. Return a tuple (y, a) where y is the received signal and a is the channel state information (fading coefficients).

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CodingTheory.transmit — Method
transmit(
    Ch::ZChannel,
    codeword::Vector{Int64}
) -> Vector{Int64}

Simulate transmitting a binary codeword over a Z-Channel.

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DataStructures.capacity — Method
capacity(Ch::BAWGNChannel) -> Float64

Return the exact BPSK-constrained capacity of the BAWGN channel via numerical integration.

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DataStructures.capacity — Method
capacity(Ch::RayleighFadingChannel) -> Any

Return the Ergodic Shannon capacity of the Rayleigh Fading channel assuming BPSK modulation.

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CodingTheory.BAWGNChannel — Type
struct BAWGNChannel <: AbstractContinuousChannel

Binary-Input Additive White Gaussian Noise (BIAWGN) Channel, defined by noise standard deviation σ. Also available as BAWGNC.

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