Initial Setup

Create a channel that adds white Gaussian noise (WGN) to an input signal. Set the noise variance to 1.5.

nVar = 1.5; chan = comm.AWGNChannel('NoiseMethod','Variance','Variance',nVar);

Create a binary phase shift keying (BSPK) modulator and demodulator.

bpskMod = comm.BPSKModulator; bpskDemod = comm.BPSKDemodulator('DecisionMethod',...'Approximate log-likelihood ratio','Variance',nVar);

Simulate a Frame

Perform polar encoding of a random message of lengthK. The rate-matched output is of lengthE.

K = 132; E = 256; msg = randi([0 1],K,1,'int8'); enc = nrPolarEncode(msg,E);

Modulate the polar encoded data using BSPK modulation, add WGN, and demodulate.

mod = bpskMod(enc); rSig = chan(mod); rxLLR = bpskDemod(rSig);

Perform polar decoding using successive-cancellation list decoder of lengthL.

L = 8; rxBits = nrPolarDecode(rxLLR,K,E,L);

Determine the number of bit errors.

numBitErrs = biterr(rxBits,msg); disp(['Number of bit errors: 'num2str(numBitErrs)])

Number of bit errors: 0

The transmitted and received messages are identical.