def turbo_encode(msg_bits, trellis1, trellis2, interleaver):
""" Turbo Encoder.
Encode Bits using a parallel concatenated rate-1/3
turbo code consisting of two rate-1/2 systematic
convolutional component codes.
Parameters
----------
msg_bits : 1D ndarray containing {0, 1}
Stream of bits to be turbo encoded.
trellis1 : Trellis object
Trellis representation of the
first code in the parallel concatenation.
trellis2 : Trellis object
Trellis representation of the
second code in the parallel concatenation.
interleaver : Interleaver object
Interleaver used in the turbo code.
Returns
-------
[sys_stream, non_sys_stream1, non_sys_stream2] : list of 1D ndarrays
Encoded bit streams corresponding
to the systematic output
and the two non-systematic
outputs from the two component codes.
"""
stream = conv_encode(msg_bits, trellis1, 'rsc')
#print('This is after stream 1')
sys_stream = stream[::2]
non_sys_stream_1 = stream[1::2]
interlv_msg_bits = interleaver.interlv(sys_stream)
puncture_matrix = array([[0, 1]])
#print('interlv_msg_bits', interlv_msg_bits)
non_sys_stream_2 = conv_encode(interlv_msg_bits, trellis2, 'rsc', puncture_matrix)
#print('This is after stream 2')
sys_stream = sys_stream[0:-trellis1.total_memory]
non_sys_stream_1 = non_sys_stream_1[0:-trellis1.total_memory]
non_sys_stream_2 = non_sys_stream_2[0:-trellis2.total_memory]
return [sys_stream, non_sys_stream_1, non_sys_stream_2]
def turbo_encode(msg_bits, trellis1, trellis2, interleaver):
""" Turbo Encoder.
Encode Bits using a parallel concatenated rate-1/3
turbo code consisting of two rate-1/2 systematic
convolutional component codes.
Parameters
----------
msg_bits : 1D ndarray containing {0, 1}
Stream of bits to be turbo encoded.
trellis1 : Trellis object
Trellis representation of the
first code in the parallel concatenation.
trellis2 : Trellis object
Trellis representation of the
second code in the parallel concatenation.
interleaver : Interleaver object
Interleaver used in the turbo code.
Returns
-------
[sys_stream, non_sys_stream1, non_sys_stream2] : list of 1D ndarrays
Encoded bit streams corresponding
to the systematic output
and the two non-systematic
outputs from the two component codes.
"""
stream = conv_encode(msg_bits, trellis1, 'rsc')
sys_stream = stream[::2]
non_sys_stream_1 = stream[1::2]
interlv_msg_bits = interleaver.interlv(sys_stream)
puncture_matrix = array([[0, 1]])
non_sys_stream_2 = conv_encode(interlv_msg_bits, trellis2, 'rsc', puncture_matrix)
sys_stream = sys_stream[0:-trellis1.total_memory]
non_sys_stream_1 = non_sys_stream_1[0:-trellis1.total_memory]
non_sys_stream_2 = non_sys_stream_2[0:-trellis2.total_memory]
return [sys_stream, non_sys_stream_1, non_sys_stream_2]