System Design

A link-level simulator implements the full chain: Source $\to$ Encoder $\to$ Modulator $\to$ Channel $\to$ Detector $\to$ Decoder $\to$ Sink

Each component is a modular Python class with a common interface.

The MIMO-OFDM input-output relation per subcarrier:

$$\mathbf{y}_k = \mathbf{H}_k \mathbf{x}_k + \mathbf{n}_k$$

where $\mathbf{H}_k \in \mathbb{C}^{N_r \times N_t}$ is the channel at subcarrier $k$.

LDPC codes are defined by a sparse parity-check matrix $\mathbf{H}$ with $M$ checks and $N$ variable nodes. Belief propagation decoding iterates messages between variable and check nodes.

AMC selects modulation and coding rate based on channel quality: