LDPC Encode and Decode QPSK-Modulated Signal in Simulink

Transmit an LDPC-encoded, QPSK-modulated bit stream through an AWGN channel. Demodulate and decode the received signal. Compute the error statistics.

The snr variable is initialized using the InitFcn callback in Model Properties>Callbacks. The SNR dB parameter in the AWGN Channel block and the Variance parameter in the QPSK Demodulator Baseband block initialize settings using the snr variable.

The simulation is configured to process one input frame of data. The Error Rate Calculation block compares the transmitted binary data stream with the information data bits output by the LDPC Decoder block.

For SNR = 1 dB, the error rate is 0.