def test_conv_encode_viterbi_decode(self):
niters = 10
blocklength = 1000
for i in range(niters):
msg = randint(0, 2, blocklength)
coded_bits = conv_encode(msg, self.trellis_1)
decoded_bits = viterbi_decode(coded_bits.astype(float),
self.trellis_1, 15)
assert_array_equal(decoded_bits[:-2], msg)
coded_bits = conv_encode(msg, self.trellis_1)
coded_syms = 2.0 * coded_bits - 1
decoded_bits = viterbi_decode(coded_syms, self.trellis_1, 15,
'unquantized')
assert_array_equal(decoded_bits[:-2], msg)
coded_bits = conv_encode(msg, self.trellis_2)
decoded_bits = viterbi_decode(coded_bits.astype(float),
self.trellis_2, 15)
assert_array_equal(decoded_bits[:-2], msg)
coded_bits = conv_encode(msg, self.trellis_2)
coded_syms = 2.0 * coded_bits - 1
decoded_bits = viterbi_decode(coded_syms, self.trellis_2, 15,
'unquantized')
assert_array_equal(decoded_bits[:-2], msg)
def commpy_decode_batch(self,y):
u_hat0 = cc.viterbi_decode(y[0], self.trellisNSC, self.tb_depth,'unquantized')
u_hat = np.empty(shape=[y.shape[0],len(u_hat0)],dtype=np.int8)
u_hat[0] = u_hat0
for i in range(len(y)-1):
u_hat[i+1] = cc.viterbi_decode(y[i+1], self.trellisNSC, self.tb_depth,'unquantized')
return u_hat
def test_conv_encode_viterbi_decode(self):
niters = 10
blocklength = 1000
for i in xrange(niters):
msg = randint(0, 2, blocklength)
coded_bits = conv_encode(msg, self.trellis_1)
decoded_bits = viterbi_decode(coded_bits.astype(float), self.trellis_1, 15)
assert_array_equal(decoded_bits[:-2], msg)
coded_bits = conv_encode(msg, self.trellis_2)
decoded_bits = viterbi_decode(coded_bits.astype(float), self.trellis_2, 15)
assert_array_equal(decoded_bits[:-2], msg)
def decode(self, encoded: np.ndarray) -> np.ndarray:
"""
Use the configured trellis to perform vitirbi decoding algorithm on the received encoded bits.
:param encoded: array of bits encoded then received
:return: array of decoded message bits that were originally encoded (with probability varying by signal noise)
"""
# decode the probable bits from the encoded string
decoded = cc.viterbi_decode(encoded,
self._trellis,
decoding_type='hard')
# return the bytes from the decoded bits
message = np.packbits(decoded, bitorder='big')
# detect message length and truncate
message_length = int.from_bytes(message[0:LENGTH_SIZE],
byteorder='big',
signed=False)
if message_length > len(message) - LENGTH_SIZE:
raise RuntimeError('Invalid message-length tag')
message = message[LENGTH_SIZE:LENGTH_SIZE + message_length]
logging.info(
'Decoded {} convolution coded parity bits into {}-byte message'.
format(len(encoded), message_length))
return message
def conv_decoder(coded_bits):
generator_matrix = np.array([[05, 07]])
M = np.array([2])
trellis = cc.Trellis(M, generator_matrix)
tb_depth = 5 * (M.sum() + 1)
return 2 * cc.viterbi_decode(
((coded_bits + 1) / 2).astype(float), trellis, tb_depth) - 1
def test_radio_encoder():
"""Online tool to visualize Encoder:
http://www.ee.unb.ca/cgi-bin/tervo/viterbi.pl
"""
# Create a fake packet
packet = [0, 0, 1, 1]
# Test convolution code encoder at different memory size
EncoderTest = namedtuple('EncoderTest', ['trellis', 'wanted'])
tests = [
EncoderTest(
None, # default option (r= 1/2, k=3)
np.array([0, 0, 0, 0, 1, 1, 0, 1])),
EncoderTest(build_trellis_structure(1, 2, constraint_len=4),
np.array([0, 0, 0, 0, 1, 1, 0, 1])),
EncoderTest(build_trellis_structure(1, 3, constraint_len=4),
np.array([0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0])),
]
for test in tests:
tx = RadioTransmitter(0, 0, 'qpsk', test.trellis)
# Test correctness of encoder
got, _ = tx._simulate_radio_transmitter(packet)
np.testing.assert_array_equal(got, test.wanted)
# Test correctness of output message by decoding with Viterbi
decoded = viterbi_decode(got, tx.trellis, 4)
np.testing.assert_array_equal(packet, decoded)
def turbo_compute((idx, x)):
'''
Compute Turbo Decoding in 1 iterations for one SNR point.
'''
np.random.seed()
message_bits = np.random.randint(0, 2, args.block_len)
coded_bits = cc.conv_encode(message_bits, trellis1)
received = corrupt_signal(coded_bits,
noise_type=args.noise_type,
sigma=test_sigmas[idx],
vv=args.v,
radar_power=args.radar_power,
radar_prob=args.radar_prob,
denoise_thd=args.radar_denoise_thd)
# make fair comparison between (100, 204) convolutional code and (100,200) RNN decoder, set the additional bit to 0
received[-2 * int(M):] = 0.0
decoded_bits = cc.viterbi_decode(received.astype(float),
trellis1,
tb_depth,
decoding_type='unquantized')
decoded_bits = decoded_bits[:-int(M)]
num_bit_errors = hamming_dist(message_bits, decoded_bits)
return num_bit_errors
def fec_decoder(self, data_in):
memory = np.array([6])
g_matrix = np.array([[91, 121]
]) # G(D) = [1+D^2+D^3+D^5+D^6, 1+D+D^2+D^3+D^6]
trellis = cc.Trellis(memory, g_matrix)
data_out = cc.viterbi_decode(data_in,
trellis,
tb_depth=int(len(data_in) / 2))
return data_out[:-6]
def conv_decoder(coded_bits):
generator_matrix = np.array([[05, 07]])
M = np.array([2])
trellis = cc.Trellis(M, generator_matrix)
tb_depth = 5 * (M.sum() + 1)
return cc.viterbi_decode(coded_bits.astype(float),
trellis,
tb_depth,
decoding_type='unquantized')
def convdecode(self, symbols):
# better do only once:
self.memory = np.array([2])
self.g_matrix = np.array([[0o7, 0o5]])
self.tr = Trellis(self.memory, self.g_matrix, 0, 'default')
#
x = list(chr(s+ord('0')) for s in symbols)
bits = np.array(x)
decoded = viterbi_decode(bits, self.tr, 15)
return decoded
def decoder_soft(msg):
msg_d = msg
puncture_matrix = Wifi80211._get_puncture_matrix(coding[0], coding[1])
if puncture_matrix:
try:
msg_d = cc.depuncturing(msg, puncture_matrix, math.ceil(len(msg) * coding[0] / coding[1] * 2))
except IndexError as e:
print(e)
print("Decoded message size %d" % (math.ceil(len(msg) * coding[0] / coding[1] * 2)))
print("Encoded message size %d" % len(msg))
print("Coding %d/%d" % (coding[0], coding[1]))
return cc.viterbi_decode(msg_d, trellis1, decoding_type='soft')
def test_conv_encode_viterbi_decode(self):
niters = 10
blocklength = 1000
for n in range(niters):
msg = randint(0, 2, blocklength)
# Previous tests
for i in range(len(self.trellis)):
coded_bits = conv_encode(msg, self.trellis[i])
decoded_bits = viterbi_decode(coded_bits.astype(float),
self.trellis[i], 15)
assert_array_equal(decoded_bits[:len(msg)], msg)
coded_bits = conv_encode(msg,
self.trellis[i],
termination='cont')
decoded_bits = viterbi_decode(coded_bits.astype(float),
self.trellis[i], 15)
assert_array_equal(decoded_bits, msg)
coded_bits = conv_encode(msg, self.trellis[i])
coded_syms = 2.0 * coded_bits - 1
decoded_bits = viterbi_decode(coded_syms, self.trellis[i], 15,
'unquantized')
assert_array_equal(decoded_bits[:len(msg)], msg)
coded_bits = conv_encode(msg, self.trellis[i])
coded_syms = 10.0 * coded_bits - 5 + randn(len(coded_bits)) * 2
decoded_bits = viterbi_decode(coded_syms, self.trellis[i], 15,
'soft')
assert_array_equal(decoded_bits[:len(msg)], msg)
coded_bits = conv_encode(msg,
self.trellis[i],
termination='cont')
coded_syms = 10.0 * coded_bits - 5 + randn(len(coded_bits)) * 2
decoded_bits = viterbi_decode(coded_syms, self.trellis[i], 15,
'soft')
assert_array_equal(decoded_bits, msg)
coded_bits = conv_encode(msg, self.trellis[i])
coded_syms = (2.0 * coded_bits - 1) * inf
decoded_bits = viterbi_decode(coded_syms, self.trellis[i], 15,
'soft')
assert_array_equal(decoded_bits[:len(msg)], msg)
coded = conv_encode(msg, self.trellis[i], termination='cont')
coded_bits = coded.astype(float)
coded_bits[coded_bits == 1.0] = inf
coded_bits[coded_bits == 0.0] = -inf
decoded_bits = viterbi_decode(coded_bits, self.trellis[i], 15,
'soft')
assert_array_equal(decoded_bits, msg)
def viterbi_decode(self, bits, signal=None):
if signal is None:
ht = False
rate = 6
else:
ht, rate, mcs = signal.ht, signal.rate, signal.mcs
if (not ht and rate in [9, 18, 36, 54]) or (ht and mcs in [2, 4, 6]):
print '[PUNCTURE] 3/4'
# 3/4
new_bits = []
for i in range(0, len(bits), 12):
new_bits.extend(bits[i:i + 3])
new_bits.extend([2, 2])
new_bits.extend(bits[i + 3:i + 7])
new_bits.extend([2, 2])
new_bits.extend(bits[i + 7:i + 11])
new_bits.extend([2, 2])
new_bits.extend(bits[i + 11:i + 12])
bits = new_bits
elif (not ht and rate in [48]) or (ht and mcs in [5]):
print '[PUNCTURE] 2/3'
# 2/3
new_bits = []
for i in range(0, len(bits), 9):
new_bits.extend(bits[i:i + 3])
new_bits.append(2)
new_bits.extend(bits[i + 3:i + 6])
new_bits.append(2)
new_bits.extend(bits[i + 6:i + 9])
new_bits.append(2)
bits = new_bits
elif ht and mcs in [7]:
print '[PUNCTURE] 5/6'
# 5/6
new_bits = []
for i in range(0, len(bits), 6):
new_bits.extend(bits[i:i + 3])
new_bits.extend([2, 2])
new_bits.extend(bits[i + 3:i + 5])
new_bits.extend([2, 2])
new_bits.append(bits[i + 5])
bits = new_bits
else:
print '[NO PUNCTURE]'
extended_bits = np.array([0] * 2 + bits + [0] * 12)
trellis = cc.Trellis(np.array([7]), np.array([[0133, 0171]]))
return list(cc.viterbi_decode(extended_bits, trellis,
tb_depth=35))[:-7]
def viterbi_decode_sequences(encoded_seqs, L, rate=1 / 2):
"""
Given a list of convolutionally encoded sequences, uses the Viterbi
algorithm on each element to decode it using a hard-decision boundary.
The Trellis is generated as per the specified L and k.
Returns a list of decoded elements.
"""
decoded_seqs = [None for _ in range(len(encoded_seqs))]
generator_matrix = gen_gmatrix(L, rate)
memory = np.array([L - 1])
trellis = cc.Trellis(memory, generator_matrix)
for i, encoded_seq in enumerate(encoded_seqs):
decoded_seq = cc.viterbi_decode(encoded_seq.astype(float), trellis)
decoded_seqs[i] = decoded_seq
return decoded_seqs
def conv_decoder(codeword_bits, trellis, tb_depth): return cc.viterbi_decode(codeword_bits.astype(float), trellis, tb_depth, decoding_type = 'unquantized')
if NType == 'iid':
noise = test_sigmas[idx] * np.random.standard_normal(
coded_bits.shape) # Define noise
uu = np.sqrt(0.5) * np.random.standard_normal(coded_bits.shape)
vv = np.sqrt(0.5) * np.random.standard_normal(coded_bits.shape)
rayleigh_coeff = np.sqrt(uu**2 + vv**2)
received = rayleigh_coeff * (2 * coded_bits -
1) + noise # Modulation plus noise
# print('received: ')
# print(received)
decoded_bits = cc.viterbi_decode(received.astype(float),
trellis,
tb_depth,
decoding_type='unquantized')
received_odd = received[::2] # first, third, fifth, etc
received_even = received[1::2] # second, fourth, sixth, etc
_, map_decoded_bits = commpy.channelcoding.map_decode(
sys_symbols=received_odd.astype(float),
non_sys_symbols=received_even.astype(float),
trellis=trellis,
noise_variance=test_sigmas[idx]**2,
L_int=np.zeros(received_odd.shape),
mode='decode')
# print('decoded_bits: ')
# print(decoded_bits)
num_bit_errors = hamming_dist(message_bits, decoded_bits[:-int(M)])
for trellis in (trellis1, trellis2, trellis3):
for i in range(10):
# Generate random message bits to be encoded
message_bits = np.random.randint(0, 2, 1000)
# Encode message bits
coded_bits = cc.conv_encode(message_bits, trellis)
# Introduce bit errors (channel)
coded_bits[np.random.randint(0, 1000)] = 0
coded_bits[np.random.randint(0, 1000)] = 0
coded_bits[np.random.randint(0, 1000)] = 1
coded_bits[np.random.randint(0, 1000)] = 1
# Decode the received bits
decoded_bits = cc.viterbi_decode(coded_bits.astype(float), trellis,
tb_depth)
num_bit_errors = util.hamming_dist(message_bits,
decoded_bits[:len(message_bits)])
if num_bit_errors != 0:
print(num_bit_errors, "Bit Errors found!")
elif i == 9:
print("No Bit Errors :)")
# ==================================================================================================
# Complete example using Commpy features and compare hard and soft demodulation. Example with code 1
# ==================================================================================================
# Modem : QPSK
modem = mod.QAMModem(4)
# g_matrix = array([[ 109 , 79]]) # G(D) = [1+D^2, 1+D+D^2]
memory = array([3])
g_matrix = array([[ 109 , 79]]) # G(D) = [1+D^2, 1+D+D^2]
trellis = cc.Trellis(memory, g_matrix)
# a='111101011'
# message_bits = np.array(list(a))
# coded_bits = cc.conv_encode(message_bits, trellis, code_type='default', puncture_matrix=None)
# print(coded_bits)
bit_num = 8414
print(bit_num)
num_bin = '{:016b}'.format(bit_num)
num_bits = [ ]
for i in num_bin:
if i =='0':
num_bits.append(0)
elif i == '1':
num_bits.append(1)
num_encoded = cc.conv_encode(num_bits, trellis, code_type='default', puncture_matrix=None)
print(num_encoded)
# coded_bits = np.array([0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0])
# print(coded_bits)
ans = cc.viterbi_decode(num_encoded, trellis, tb_depth=None, decoding_type='hard')
print(ans)
# print(str(message_bits))
# ans = np.array2string(np.random.randint(0,2,10000))
# ans+= '\n'
# print (ans)
# output_file = open("INPUT.txt", "w")
# output_file.write(ans)
def decoder_hard(msg):
return cc.viterbi_decode(msg, trellis1)
def commpy_decode_sequence(self,y):
return cc.viterbi_decode(y, self.trellisNSC, self.tb_depth,'unquantized')
def decode(v): # demodulate and decode
idx = 0
# Decode the Bit Length
print('Bit Length Packet...')
idx = find_header(v, idx)
start_point = idx
ans = [] # received bit list
for i in range(
2 * (16 + memory_len)
): # 32 bit for bit_len info (add mempry_len due to conv code prop)
bit = v[idx:idx + bit_len]
weight0 = get_weight(signal_zero, bit)
weight1 = get_weight(signal_one, bit)
if weight0 >= weight1: ans.append(0)
else: ans.append(1)
idx += bit_len
# print(ans)
# decode bit length info by Veterbi Algorithm
ans = np.array(ans)
ans = cc.viterbi_decode(ans, trellis, tb_depth=None,
decoding_type='hard')[:-memory_len]
num_decoded = ''
for i in range(len(ans)):
if ans[i] == 1:
num_decoded += '1'
elif ans[i] == 0:
num_decoded += '0'
#Print encoded and decoded bit num
# print('bit num endoded info: ', num_decoded)
bit_num = int(num_decoded, 2)
print('The num of bits will be received is: ', bit_num)
# Decode Text Part
ans = []
packet_num = 0
for j in range(bit_num):
if j % packet_size == 0: # if a new packet begin
idx += 3 * bit_len
packet_num += 1
print('\nText info packet', packet_num)
idx = find_header(v, idx) # Re-synchronize
bit = v[idx:idx + bit_len]
weight0 = get_weight(signal_zero, bit)
weight1 = get_weight(signal_one, bit)
if weight0 >= weight1: ans.append(0)
else: ans.append(1)
# ans.append(weight1)
idx += bit_len
end_point = idx
# decode by Veterbi Algorithm
ans = np.array(ans)
ans = cc.viterbi_decode(ans, trellis, tb_depth=None,
decoding_type='hard')[:-memory_len]
text_decoded = ''
for i in range(len(ans)):
if ans[i] == 1:
text_decoded += '1'
elif ans[i] == 0:
text_decoded += '0'
if test:
f = open("INPUT.txt", 'r')
context = f.readlines()
f.close()
if (len(context) != 1):
print("wrong input file")
exit()
text = context[0]
print('\nTransimission time: ',
(end_point - start_point) / sd.default.samplerate, 's')
print('Receive encoded bit num: ', bit_num)
print('Receive decoded bit num: ', len(text_decoded))
print('Actual send bit', len(text))
err = 0
err_list = []
for i in range(min(len(text_decoded), len(text))):
if text[i] != text_decoded[i]:
err += 1
err_list.append(i)
print("Total error bit num : ", err)
print('Acuuracy rate :', 1 - err / len(text))
print('Error list:', err_list, '\n')
output_file = open("OUTPUT.txt", "w")
output_file.write(text_decoded)
else:
output_file = open("OUTPUT.txt", "w")
output_file.write(text_decoded)
# ############################################
# Abandon as of now
# # include repeat
# else:
# print('Begin to decode the first packet....')
# ans_list = []
# bit_num = 0
# max_power = 0
# last_power = 0
# while True:
# bit = v[idx : idx + bit_len]
# power = np.dot(preamble, v[idx : idx + 5 * bit_len])
# energy = np.linalg.norm(bit)
# # print (energy)
# # print(power)
# if power < last_power and last_power == max_power and last_power > 15*energy and power > 0 :
# # print('Received bit num',bit_num-1)
# ans = ans[:-1]
# break
# last_power = power
# max_power = max(max_power,power)
# weight0 = sum(signal_zero * bit)
# weight1 = sum(signal_one * bit)
# # print ('0 weight: ', weight0)
# # print('1 weight:', weight1)
# ans_list.append([weight0,weight1])
# idx += bit_len
# bit_num += 1
# print('\nLooking for the scond packet...')
# n = idx + 10*bit_len
# power = np.dot(preamble, v[n: n + 5 * bit_len])
# # according to the device
# # find the header
# while power < threshold:
# power = np.dot(preamble, v[n: n + 5 * bit_len])
# n += 1
# print("first step :",n)
# max_power = 0
# header = n
# for i in range(1, 1):
# curr_power = np.dot(preamble, v[n + i: n + i + 5 * bit_len])
# if curr_power > max_power:
# max_power = curr_power
# header = n + i
# print("second step :",header)
# idx = header + bit_len * 5 # pass the preamble
# print('Begin to decode the second packet....')
# first_bit_num = bit_num -2
# bit_num = 0
# max_power = 0
# last_power = 0
# while True:
# if bit_num > first_bit_num:
# break
# bit = v[idx : idx + bit_len]
# power = np.dot(preamble, v[idx : idx + 5 * bit_len])
# energy = np.linalg.norm(bit)
# # print (energy)
# # print(power)
# if power < last_power and last_power == max_power and last_power > 15*energy and power > 0 :
# ans = ans[:-1]
# break
# last_power = power
# max_power = max(max_power,power)
# weight0 = sum(signal_zero * bit)
# weight1 = sum(signal_one * bit)
# ans_list[bit_num][0]+= weight0
# ans_list[bit_num][1]+= weight1
# idx += bit_len
# bit_num += 1
# for i in range(bit_num):
# if ans_list[i][0] >= ans_list[i][1]:
# ans.append(0)
# else:
# ans.append(1)
# ans = np.array(ans)
# ans = cc.viterbi_decode(ans, trellis, tb_depth=None, decoding_type='hard')[:-2]
# text_decoded = ''
# for i in range(len(ans)):
# if ans[i] == 1:
# text_decoded +='1'
# elif ans[i] == 0:
# text_decoded +='0'
# if test:
# f = open("INPUT.txt", 'r')
# context = f.readlines()
# f.close()
# if (len(context) != 1):
# print("wrong input file")
# exit()
# text = context[0]
# print(text_decoded)
# print(text)
# print('Receive bit num: ',bit_num)
# print('Text bit num', len(text))
# err = 0
# err_list = []
# for i in range(len(text)):
# if text[i] != text_decoded[i]:
# err += 1
# err_list.append(i)
# print("total error : ", err)
# print('error rate :' , err/bit_num)
# print('error list:', err_list)
# else:
# print('Receive bit num: ',bit_num)
# print('Decode as below: ')
# print(ans)
# output_file = open("OUTPUT.txt", "w")
# output_file.write(ans)
def decoder_soft(msg):
return cc.viterbi_decode(msg, trellis1, decoding_type='soft')
# Traceback depth of the decoder
tb_depth = 5*(M.sum() + 1)
for i in range(10):
# Generate random message bits to be encoded
message_bits = np.random.randint(0, 2, 1000)
# Encode message bits
coded_bits = cc.conv_encode(message_bits, trellis)
# Introduce bit errors (channel)
#coded_bits[4] = 0
#coded_bits[7] = 0
# Decode the received bits
decoded_bits = cc.viterbi_decode(coded_bits.astype(float), trellis, tb_depth)
num_bit_errors = hamming_dist(message_bits, decoded_bits[:-M])
#num_bit_errors = 1
if num_bit_errors !=0:
#print(num_bit_errors, "Bit Errors found!")
#print(message_bits)
#print(decoded_bits[tb_depth+3:])
#print(decoded_bits)
break
else:
print("No Bit Errors :)")
#print("==== Message Bits ===")
#print(message_bits)
