70 lines
1.6 KiB
Python
Executable File
70 lines
1.6 KiB
Python
Executable File
#!/usr/bin/env python3.7
|
|
|
|
"""
|
|
Shitty OFDM simulator designed to make it so I understand OFDM.
|
|
Hopefully eventually this modem design makes it onto an fpga.
|
|
|
|
TODO:
|
|
Add comments for functions
|
|
Explain what the main function is doing
|
|
Finish doing the channel simulation stuff (add noise, and verify channel response)
|
|
Add support for 16-QAM, 64-QAM, etc...
|
|
Add channel estimation via pilot carriers
|
|
Add some sort of payload support, i.e. be able to drop the padding at the end
|
|
|
|
"""
|
|
|
|
import numpy as np
|
|
import matplotlib.pyplot as plt
|
|
|
|
import channel
|
|
import qam
|
|
|
|
from serpar import parallelise, serialise
|
|
|
|
def cp_add(in_data, prefix_len):
|
|
out_data = np.ndarray((len(in_data), len(in_data[0]) + prefix_len), dtype=np.csingle)
|
|
|
|
for i in range(len(in_data)):
|
|
cp = in_data[i][-prefix_len:]
|
|
out_data[i] = np.hstack([cp, in_data[i]])
|
|
|
|
return out_data
|
|
|
|
def cp_remove(in_data, prefix_len):
|
|
out_data = np.ndarray((len(in_data), len(in_data[0]) - prefix_len), dtype=np.csingle)
|
|
|
|
for i in range(len(in_data)):
|
|
out_data[i] = in_data[i][prefix_len:]
|
|
|
|
return out_data
|
|
|
|
|
|
|
|
|
|
if __name__ == '__main__':
|
|
with open('data.txt', 'r') as file:
|
|
data = file.read()
|
|
|
|
bytes = bytearray(data, 'utf8')
|
|
|
|
parallel = parallelise(16, bytes)
|
|
|
|
modulated = qam.modulate(parallel)
|
|
|
|
ofdm_time = np.fft.ifft(modulated)
|
|
|
|
ofdm_prefixed = cp_add(ofdm_time, 4)
|
|
|
|
# Put the channel simulator stuff here
|
|
|
|
ofdm_cp_removed = cp_remove(ofdm_prefixed, 4)
|
|
|
|
to_decode = np.fft.fft(ofdm_cp_removed)
|
|
|
|
to_serialise = qam.demodulate(to_decode)
|
|
|
|
data = serialise(16, to_serialise)
|
|
|
|
print(data)
|