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https://github.com/jhshi/openofdm.git
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58 lines
1.6 KiB
Python
58 lines
1.6 KiB
Python
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# Authors: Veeresh Taranalli <veeresht@gmail.com>
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# License: BSD 3-Clause
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import numpy as np
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import commpy.channelcoding.convcode as cc
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from commpy.utilities import *
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# =============================================================================
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# Example showing the encoding and decoding of convolutional codes
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# =============================================================================
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# G(D) corresponding to the convolutional encoder
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generator_matrix = np.array([[05, 07]])
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#generator_matrix = np.array([[03, 00, 02], [07, 04, 06]])
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# Number of delay elements in the convolutional encoder
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M = np.array([2])
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# Create trellis data structure
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trellis = cc.Trellis(M, generator_matrix)
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# Traceback depth of the decoder
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tb_depth = 5*(M.sum() + 1)
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for i in range(10):
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# Generate random message bits to be encoded
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message_bits = np.random.randint(0, 2, 1000)
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# Encode message bits
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coded_bits = cc.conv_encode(message_bits, trellis)
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# Introduce bit errors (channel)
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#coded_bits[4] = 0
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#coded_bits[7] = 0
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# Decode the received bits
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decoded_bits = cc.viterbi_decode(coded_bits.astype(float), trellis, tb_depth)
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num_bit_errors = hamming_dist(message_bits, decoded_bits[:-M])
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#num_bit_errors = 1
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if num_bit_errors !=0:
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#print num_bit_errors, "Bit Errors found!"
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#print message_bits
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#print decoded_bits[tb_depth+3:]
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#print decoded_bits
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break
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else:
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print "No Bit Errors :)"
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#print "==== Message Bits ==="
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#print message_bits
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#print "==== Coded Bits ====="
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#print coded_bits
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#print "==== Decoded Bits ==="
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#print decoded_bits[tb_depth:]
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