How to use modulations other than BPSK(eg. QPSK)?

[MacroMicroMichael]

Thanks for your work. It seems that the encoder uses BPSK modulation in default. Where should I change the code to use QPSK modulation?

[JrunDing]

I have the same question. How did you solve this?

[MacroMicroMichael]

I have the same question. How did you solve this?

I change its source code by removing the BPSK and then add QPSK manually.

[JrunDing]

I can change modulation in encoder.py, but how to change modulation in decoder.py?

[MacroMicroMichael]

Here's my version of the modification and hope that helps. In decoder.py, I map QPSK's complex sequence back to the real sequence and then calculate the LLR. Here's the code: (the mapping rule may be different)

    tmp = np.empty((2*y.shape[0], y.shape[1]))
    for j in range(tmp.shape[1]):
        for i in range(tmp.shape[0]):
            tmp[i,j] = y[i//2,j].real if i%2==0 else y[i//2,j].imag
    Lc = 2 * tmp / var # MSE

    Lc = Lc.astype('float64')

Then Lc is sent into BP algorithm for demodulation the same as before.

[JrunDing]

Thanks for the reply but I still have a question. Why do you map the complex sequence of QPSK back to the real sequence (floating point, floating point, floating point) in this way instead of QPSK demodulation (0, 1, 0, 1)? I dont know how to use 64QAM.

[JrunDing]

Thanks!! I have solved this problem!

[Zhu0518]

Thanks!! I have solved this problem!

How did you solve your questions about 64QAM?