247 lines
12 KiB
Python
Executable File
247 lines
12 KiB
Python
Executable File
#!/usr/bin/env python
|
|
#
|
|
# This work is licensed under the Creative Attribution-NonCommercial-ShareAlike
|
|
# 3.0 Unported License.To view a copy of this license, visit
|
|
# http://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to
|
|
# Creative Commons, 444 Castro Street, Suite 900, Mountain View,
|
|
# California, 94041, USA.
|
|
|
|
from __future__ import print_function
|
|
from bitarray import bitarray
|
|
import hamming, crc, rs129
|
|
|
|
# Does anybody read this stuff? There's a PEP somewhere that says I should do this.
|
|
__author__ = 'Cortney T. Buffington, N0MJS'
|
|
__copyright__ = 'Copyright (c) 2016 Cortney T. Buffington, N0MJS and the K0USY Group'
|
|
__credits__ = 'Jonathan Naylor, G4KLX; Ian Wraith'
|
|
__license__ = 'Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported'
|
|
__maintainer__ = 'Cort Buffington, N0MJS'
|
|
__email__ = 'n0mjs@me.com'
|
|
|
|
|
|
#------------------------------------------------------------------------------
|
|
# Interleaver Index
|
|
#------------------------------------------------------------------------------
|
|
|
|
INDEX_181 = (
|
|
0, 181, 166, 151, 136, 121, 106, 91, 76, 61, 46, 31, 16, 1, 182, 167, 152, 137,
|
|
122, 107, 92, 77, 62, 47, 32, 17, 2, 183, 168, 153, 138, 123, 108, 93, 78, 63,
|
|
48, 33, 18, 3, 184, 169, 154, 139, 124, 109, 94, 79, 64, 49, 34, 19, 4, 185, 170,
|
|
155, 140, 125, 110, 95, 80, 65, 50, 35, 20, 5, 186, 171, 156, 141, 126, 111, 96,
|
|
81, 66, 51, 36, 21, 6, 187, 172, 157, 142, 127, 112, 97, 82, 67, 52, 37, 22, 7,
|
|
188, 173, 158, 143, 128, 113, 98, 83, 68, 53, 38, 23, 8, 189, 174, 159, 144, 129,
|
|
114, 99, 84, 69, 54, 39, 24, 9, 190, 175, 160, 145, 130, 115, 100, 85, 70, 55, 40,
|
|
25, 10, 191, 176, 161, 146, 131, 116, 101, 86, 71, 56, 41, 26, 11, 192, 177, 162,
|
|
147, 132, 117, 102, 87, 72, 57, 42, 27, 12, 193, 178, 163, 148, 133, 118, 103, 88,
|
|
73, 58, 43, 28, 13, 194, 179, 164, 149, 134, 119, 104, 89, 74, 59, 44, 29, 14,
|
|
195, 180, 165, 150, 135, 120, 105, 90, 75, 60, 45, 30, 15)
|
|
|
|
|
|
#------------------------------------------------------------------------------
|
|
# BPTC(196,96) Decoding Routings
|
|
#------------------------------------------------------------------------------
|
|
|
|
def decode_full_lc(_data):
|
|
binlc = bitarray(endian='big')
|
|
binlc.extend([_data[136],_data[121],_data[106],_data[91], _data[76], _data[61], _data[46], _data[31]])
|
|
binlc.extend([_data[152],_data[137],_data[122],_data[107],_data[92], _data[77], _data[62], _data[47], _data[32], _data[17], _data[2] ])
|
|
binlc.extend([_data[123],_data[108],_data[93], _data[78], _data[63], _data[48], _data[33], _data[18], _data[3], _data[184],_data[169]])
|
|
binlc.extend([_data[94], _data[79], _data[64], _data[49], _data[34], _data[19], _data[4], _data[185],_data[170],_data[155],_data[140]])
|
|
binlc.extend([_data[65], _data[50], _data[35], _data[20], _data[5], _data[186],_data[171],_data[156],_data[141],_data[126],_data[111]])
|
|
binlc.extend([_data[36], _data[21], _data[6], _data[187],_data[172],_data[157],_data[142],_data[127],_data[112],_data[97], _data[82] ])
|
|
binlc.extend([_data[7], _data[188],_data[173],_data[158],_data[143],_data[128],_data[113],_data[98], _data[83]])
|
|
'''
|
|
This is the rest of the Full LC data -- the RS1293 FEC that we don't need
|
|
_data[68],_data[53],_data[174],_data[159],_data[144],_data[129],_data[114],_data[99],_data[84],_data[69],_data[54],_data[39],
|
|
_data[24],_data[145],_data[130],_data[115],_data[100],_data[85],_data[70],_data[55],_data[40],_data[25],_data[10],_data[191]
|
|
'''
|
|
return binlc
|
|
|
|
#------------------------------------------------------------------------------
|
|
# BPTC(196,96) Encoding Routings
|
|
#------------------------------------------------------------------------------
|
|
|
|
def interleave_19696(_data):
|
|
inter = bitarray(196, endian='big')
|
|
for index in xrange(196):
|
|
inter[INDEX_181[index]] = _data[index] # the real math is slower: deint[index] = _data[(index * 181) % 196]
|
|
return inter
|
|
|
|
# Accepts 12 byte LC header + RS1293, converts to binary and pads for 196 bit
|
|
# encode hamming 15113 to rows and 1393 to columns
|
|
def encode_19696(_data):
|
|
# Create a bitarray from the 4 bytes of LC data (includes RS1293 ECC)
|
|
_bdata = bitarray(endian='big')
|
|
_bdata.frombytes(_data)
|
|
|
|
# Insert R0-R3 bits
|
|
for i in xrange(4):
|
|
_bdata.insert(0, 0)
|
|
|
|
# Get row hamming 15,11,3 and append. +1 is to account for R3 that makes an even 196bit string
|
|
for index in xrange(9):
|
|
spos = (index*15) + 1
|
|
epos= spos + 11
|
|
_rowp = hamming.enc_15113(_bdata[spos:epos])
|
|
for pbit in xrange(4):
|
|
_bdata.insert(epos+pbit,_rowp[pbit])
|
|
|
|
# Get column hamming 13,9,3 and append. +1 is to account for R3 that makes an even 196bit string
|
|
# Pad out the bitarray to a full 196 bits. Can't insert into 'columns'
|
|
for i in xrange(60):
|
|
_bdata.append(0)
|
|
|
|
column = bitarray(9, endian='big') # Temporary bitarray to hold column data
|
|
for col in xrange(15):
|
|
spos = col + 1
|
|
for index in xrange(9):
|
|
column[index] = _bdata[spos]
|
|
spos += 15
|
|
_colp = hamming.enc_1393(column)
|
|
|
|
# Insert bits into matrix...
|
|
cpar = 136 + col # Starting location in the matrix for column bits
|
|
for pbit in xrange(4):
|
|
_bdata[cpar] = _colp[pbit]
|
|
cpar += 15
|
|
|
|
return _bdata
|
|
|
|
def encode_header_lc(_lc):
|
|
full_lc = _lc + rs129.lc_header_encode(_lc)
|
|
full_lc = encode_19696(full_lc)
|
|
full_lc = interleave_19696(full_lc)
|
|
return full_lc
|
|
|
|
def encode_terminator_lc(_lc):
|
|
lc_rs = _lc + rs129.lc_terminator_encode(_lc)
|
|
|
|
#------------------------------------------------------------------------------
|
|
# BPTC Embedded LC Decoding Routines
|
|
#------------------------------------------------------------------------------
|
|
|
|
def decode_emblc(_elc):
|
|
|
|
_binlc = bitarray(endian='big')
|
|
_binlc.extend([_elc[0],_elc[8], _elc[16],_elc[24],_elc[32],_elc[40],_elc[48],_elc[56],_elc[64],_elc[72] ,_elc[80]])
|
|
_binlc.extend([_elc[1],_elc[9], _elc[17],_elc[25],_elc[33],_elc[41],_elc[49],_elc[57],_elc[65],_elc[73] ,_elc[81]])
|
|
_binlc.extend([_elc[2],_elc[10],_elc[18],_elc[26],_elc[34],_elc[42],_elc[50],_elc[58],_elc[66],_elc[74]])
|
|
_binlc.extend([_elc[3],_elc[11],_elc[19],_elc[27],_elc[35],_elc[43],_elc[51],_elc[59],_elc[67],_elc[75]])
|
|
_binlc.extend([_elc[4],_elc[12],_elc[20],_elc[28],_elc[36],_elc[44],_elc[52],_elc[60],_elc[68],_elc[76]])
|
|
_binlc.extend([_elc[5],_elc[13],_elc[21],_elc[29],_elc[37],_elc[45],_elc[53],_elc[61],_elc[69],_elc[77]])
|
|
_binlc.extend([_elc[6],_elc[14],_elc[22],_elc[30],_elc[38],_elc[46],_elc[54],_elc[62],_elc[70],_elc[78]])
|
|
|
|
return(_binlc.tobytes())
|
|
|
|
#------------------------------------------------------------------------------
|
|
# BPTC Embedded LC Encoding Routines
|
|
#------------------------------------------------------------------------------
|
|
|
|
|
|
# Accepts 12 byte LC header + 5-bit checksum, converts to binary and builts out the BPTC
|
|
# encoded result with hamming(16,11,4) and parity.
|
|
def encode_emblc(_lc):
|
|
|
|
# Get the 5-bit checksum for the Embedded LC
|
|
_csum = crc.csum5(_lc)
|
|
|
|
# Create a bitarray from the 4 bytes of LC data (includes 5-bit checksum).
|
|
_binlc = bitarray(endian='big')
|
|
_binlc.frombytes(_lc)
|
|
|
|
# Insert the checksum bits at the right location in the matrix (this is actually faster than with a for loop)
|
|
_binlc.insert(32,_csum[0])
|
|
_binlc.insert(43,_csum[1])
|
|
_binlc.insert(54,_csum[2])
|
|
_binlc.insert(65,_csum[3])
|
|
_binlc.insert(76,_csum[4])
|
|
|
|
# Insert the hamming bits at the right location in the matrix
|
|
for index in xrange(0,112,16):
|
|
for hindex,hbit in zip(xrange(index+11,index+16), hamming.enc_16114(_binlc[index:index+11])):
|
|
_binlc.insert(hindex,hbit)
|
|
|
|
# Insert the column parity bits at the right location in the matrix
|
|
for index in xrange(0,16):
|
|
_binlc.insert(index+112, _binlc[index+0] ^ _binlc[index+16] ^ _binlc[index+32] ^ _binlc[index+48] ^ _binlc[index+64] ^ _binlc[index+80] ^ _binlc[index+96])
|
|
|
|
# Create Embedded LC segments in 48 bit blocks
|
|
emblc_b = bitarray(endian='big')
|
|
emblc_b.extend([_binlc[0], _binlc[16],_binlc[32],_binlc[48],_binlc[64],_binlc[80],_binlc[96], _binlc[112]])
|
|
emblc_b.extend([_binlc[1], _binlc[17],_binlc[33],_binlc[49],_binlc[65],_binlc[81],_binlc[97], _binlc[113]])
|
|
emblc_b.extend([_binlc[2], _binlc[18],_binlc[34],_binlc[50],_binlc[66],_binlc[82],_binlc[98], _binlc[114]])
|
|
emblc_b.extend([_binlc[3], _binlc[19],_binlc[35],_binlc[51],_binlc[67],_binlc[83],_binlc[99], _binlc[115]])
|
|
|
|
emblc_c = bitarray(endian='big')
|
|
emblc_c.extend([_binlc[4], _binlc[20],_binlc[36],_binlc[52],_binlc[68],_binlc[84],_binlc[100],_binlc[116]])
|
|
emblc_c.extend([_binlc[5], _binlc[21],_binlc[37],_binlc[53],_binlc[69],_binlc[85],_binlc[101],_binlc[117]])
|
|
emblc_c.extend([_binlc[6], _binlc[22],_binlc[38],_binlc[54],_binlc[70],_binlc[86],_binlc[102],_binlc[118]])
|
|
emblc_c.extend([_binlc[7], _binlc[23],_binlc[39],_binlc[55],_binlc[71],_binlc[87],_binlc[103],_binlc[119]])
|
|
|
|
emblc_d = bitarray(endian='big')
|
|
emblc_d.extend([_binlc[8], _binlc[24],_binlc[40],_binlc[56],_binlc[72],_binlc[88],_binlc[104],_binlc[120]])
|
|
emblc_d.extend([_binlc[9], _binlc[24],_binlc[41],_binlc[57],_binlc[73],_binlc[89],_binlc[105],_binlc[121]])
|
|
emblc_d.extend([_binlc[10],_binlc[26],_binlc[42],_binlc[58],_binlc[74],_binlc[90],_binlc[106],_binlc[122]])
|
|
emblc_d.extend([_binlc[11],_binlc[27],_binlc[43],_binlc[59],_binlc[75],_binlc[91],_binlc[107],_binlc[123]])
|
|
|
|
emblc_e = bitarray(endian='big')
|
|
emblc_e.extend([_binlc[12],_binlc[28],_binlc[44],_binlc[60],_binlc[76],_binlc[92],_binlc[108],_binlc[124]])
|
|
emblc_e.extend([_binlc[13],_binlc[29],_binlc[45],_binlc[61],_binlc[77],_binlc[93],_binlc[109],_binlc[125]])
|
|
emblc_e.extend([_binlc[14],_binlc[30],_binlc[46],_binlc[62],_binlc[78],_binlc[94],_binlc[110],_binlc[126]])
|
|
emblc_e.extend([_binlc[15],_binlc[31],_binlc[47],_binlc[63],_binlc[79],_binlc[95],_binlc[111],_binlc[127]])
|
|
|
|
return([emblc_b, emblc_c, emblc_d, emblc_e])
|
|
|
|
#------------------------------------------------------------------------------
|
|
# Used to execute the module directly to run built-in tests
|
|
#------------------------------------------------------------------------------
|
|
|
|
if __name__ == '__main__':
|
|
from binascii import b2a_hex as h
|
|
from time import time
|
|
|
|
# Validation Example
|
|
|
|
voice_h = '\x2b\x60\x04\x10\x1f\x84\x2d\xd0\x0d\xf0\x7d\x41\x04\x6d\xff\x57\xd7\x5d\xf5\xde\x30\x15\x2e\x20\x70\xb2\x0f\x80\x3f\x88\xc6\x95\xe2'
|
|
voice_hb = bitarray(endian='big')
|
|
voice_hb.frombytes(voice_h)
|
|
voice_hb = voice_hb[0:98] + voice_hb[166:264]
|
|
|
|
# Header LC -- Terminator similar
|
|
lc = '\x00\x10\x20\x00\x0c\x30\x2f\x9b\xe5' # \xda\xd4\x5a
|
|
t0 = time()
|
|
full_lc_encode = encode_header_lc(lc)
|
|
t1 = time()
|
|
encode_time = t1-t0
|
|
|
|
t0 = time()
|
|
full_lc_dec = decode_full_lc(full_lc_encode)
|
|
t1 = time()
|
|
decode_time = t1-t0
|
|
|
|
print('VALIDATION ROUTINES:')
|
|
print('Orig Data: {}, {} bytes'.format(h(lc), len(lc)))
|
|
print('Orig Encoded: {}, {} bytes'.format(h(voice_hb), len(voice_hb.tobytes())))
|
|
print()
|
|
print('BPTC(196,96):')
|
|
print('Encoded data: {}, {} bytes'.format(h(full_lc_encode.tobytes()), len(full_lc_encode.tobytes())))
|
|
print('Encoding time: {} seconds'.format(encode_time))
|
|
print('Decoded data: {}'.format(h(full_lc_dec)))
|
|
print('Decode Time: {} seconds'.format(decode_time))
|
|
|
|
# Embedded LC
|
|
t0 = time()
|
|
emblc = encode_emblc(lc)
|
|
t1 = time()
|
|
encode_time = t1 -t0
|
|
|
|
t0 = time()
|
|
decemblc = decode_emblc(emblc[0] + emblc[1] + emblc[2] + emblc[3])
|
|
t1 = time()
|
|
decode_time = t1 -t0
|
|
|
|
print('\nEMBEDDED LC:')
|
|
print('Encoded Data: Burst B:{} Burst C:{} Burst D:{} Burst E:{}'.format(h(emblc[0].tobytes()), h(emblc[1].tobytes()), h(emblc[2].tobytes()), h(emblc[3].tobytes())))
|
|
print('Endoding Time: {}'.format(encode_time))
|
|
print('Decoded data: {}'.format(h(decemblc)))
|
|
print('Decoding Time: {}'.format(decode_time)) |