Initial commit. Stuff is incomplete because I deleted it :(

main.py

@@ -0,0 +1,121 @@
+#!/usr/bin/env python3.7
+
+import numpy as np
+import matplotlib.pyplot as plt
+from math import floor, ceil
+
+from channel import channel_sim
+
+def parralelise(n, in_data):
+    """
+    Parameters:
+    n - number of channels
+    in_data - input data, array of 
+
+    Output:
+    array of OFDM symbols, each symbol
+    """
+
+    data_len = len(in_data)
+
+    # Find number of OFDM symbols
+    # Multiplied by four here because we have 2 bits per QAM symbol/channel/whatever
+    # so 8 / 2 = 4
+    symbols = float(data_len * 4 / n)
+    
+    # Check if we have to pad last symbol
+    if symbols.is_integer():
+        symbols = int(symbols)
+    else:
+        symbols = ceil(symbols)
+
+
+    # Initialise output array
+    out_data = np.ndarray(shape=(int(symbols), n), dtype=int)
+
+    # Just a way to keep track of where I am in the byte array
+    # I bet there's a more "python-y" way to do this but whatever
+    byte_index = 0
+    bit_index = 0
+
+    # Will have to be revamped if I want to do more than 4-QAM modulation
+    for i in range(symbols):
+        for j in range(n):
+            #  if we have exhausted data, pad with zeroes
+            if i == symbols - 1 and byte_index == data_len:
+                for k in range(j, n):
+                    out_data[i][k] = 0
+
+                break
+
+            # Isolate the correct bits
+            out_data[i][j] = (in_data[byte_index] >> (bit_index * 2)) & 0b11
+
+            bit_index += 1
+
+            if bit_index == 4:
+                byte_index += 1
+                bit_index = 0
+
+
+    return out_data
+
+
+
+
+def qam(n, in_data):
+    """
+    Modulates into 4-QAM encoding, might change that number later.
+
+    Parameters:
+    n - number of channels to operate on
+    in_data -  m X n array, m symbols to run on
+
+    Output:
+    data 
+    """
+
+    #initialise output array
+    out_data = np.ndarray((len(in_data), n), dtype=np.csingle)
+
+    for i in range(len(in_data)):
+        for j in range(n):
+            
+            #4-QAM is nice
+            out_data[i][j] = 1 + 1j
+
+            # Just rotate 90 degrees for every number and you've got your encoding
+            for k in range(in_data[i][j]):
+                out_data[i][j] = out_data[i][j] * (1j)
+
+    return out_data
+
+def cyclic_prefix(n, in_data, prefix_len):
+    out_data = np.ndarray((len(in_data), n + prefix_len), dtype=np.csingle)
+
+
+
+
+
+if __name__ == '__main__':
+    with open('data.txt', 'r') as file:
+        data = file.read()
+
+    bytes = bytearray(data, 'utf8')
+
+    parallel = parralelise(16, bytes)
+
+    modulated = qam(16, parallel)
+
+    tx = np.fft.ifft(modulated)
+
+    rx = channel_sim(tx)
+    
+    plt.plot(tx[0], 'r')
+    plt.plot(rx[0], 'b')
+    plt.show()
+
+    print(channel_sim(pre_modulated))
+
+
+