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gr-digitalhf/python/physical_layer/MIL_STD_188_110C.py

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Python

## -*- python -*-
from __future__ import print_function
import numpy as np
import common
from digitalhf.digitalhf_swig import viterbi27
## ---- constellations -----------------------------------------------------------
BPSK=np.array(zip(np.exp(2j*np.pi*np.arange(2)/2), [0,1]), common.CONST_DTYPE)
QPSK=np.array(zip(np.exp(2j*np.pi*np.arange(4)/4), [0,1,3,2]), common.CONST_DTYPE)
PSK8=np.array(zip(np.exp(2j*np.pi*np.arange(8)/8), [1,0,2,3,7,6,4,5]), common.CONST_DTYPE)
QAM16=np.array(
zip([+0.866025+0.500000j, 0.500000+0.866025j, 1.000000+0.000000j, 0.258819+0.258819j,
-0.500000+0.866025j, 0.000000+1.000000j, -0.866025+0.500000j, -0.258819+0.258819j,
+0.500000-0.866025j, 0.000000-1.000000j, 0.866025-0.500000j, 0.258819-0.258819j,
-0.866025-0.500000j, -0.500000-0.866025j, -1.000000+0.000000j, -0.258819-0.258819j],
range(16)), common.CONST_DTYPE)
QAM32=np.array(
zip([+0.866380+0.499386j, 0.984849+0.173415j, 0.499386+0.866380j, 0.173415+0.984849j,
+0.520246+0.520246j, 0.520246+0.173415j, 0.173415+0.520246j, 0.173415+0.173415j,
-0.866380+0.499386j, -0.984849+0.173415j, -0.499386+0.866380j, -0.173415+0.984849j,
-0.520246+0.520246j, -0.520246+0.173415j, -0.173415+0.520246j, -0.173415+0.173415j,
+0.866380-0.499386j, 0.984849-0.173415j, 0.499386-0.866380j, 0.173415-0.984849j,
+0.520246-0.520246j, 0.520246-0.173415j, 0.173415-0.520246j, 0.173415-0.173415j,
-0.866380-0.499386j, -0.984849-0.173415j, -0.499386-0.866380j, -0.173415-0.984849j,
-0.520246-0.520246j, -0.520246-0.173415j, -0.173415-0.520246j, -0.173415-0.173415j],
range(32)), common.CONST_DTYPE)
QAM64=np.array(
zip([+1.000000+0.000000j, 0.822878+0.568218j, 0.821137+0.152996j, 0.932897+0.360142j,
+0.000000-1.000000j, 0.822878-0.568218j, 0.821137-0.152996j, 0.932897-0.360142j,
+0.568218+0.822878j, 0.588429+0.588429j, 0.588429+0.117686j, 0.588429+0.353057j,
+0.568218-0.822878j, 0.588429-0.588429j, 0.588429-0.117686j, 0.588429-0.353057j,
+0.152996+0.821137j, 0.117686+0.588429j, 0.117686+0.117686j, 0.117686+0.353057j,
+0.152996-0.821137j, 0.117686-0.588429j, 0.117686-0.117686j, 0.117686-0.353057j,
+0.360142+0.932897j, 0.353057+0.588429j, 0.353057+0.117686j, 0.353057+0.353057j,
+0.360142-0.932897j, 0.353057-0.588429j, 0.353057-0.117686j, 0.353057-0.353057j,
+0.000000+1.000000j, -0.822878+0.568218j, -0.821137+0.152996j, -0.932897+0.360142j,
-1.000000+0.000000j, -0.822878-0.568218j, -0.821137-0.152996j, -0.932897-0.360142j,
-0.568218+0.822878j, -0.588429+0.588429j, -0.588429+0.117686j, -0.588429+0.353057j,
-0.568218-0.822878j, -0.588429-0.588429j, -0.588429-0.117686j, -0.588429-0.353057j,
-0.152996+0.821137j, -0.117686+0.588429j, -0.117686+0.117686j, -0.117686+0.353057j,
-0.152996-0.821137j, -0.117686-0.588429j, -0.117686-0.117686j, -0.117686-0.353057j,
-0.360142+0.932897j, -0.353057+0.588429j, -0.353057+0.117686j, -0.353057+0.353057j,
-0.360142-0.932897j, -0.353057-0.588429j, -0.353057-0.117686j, -0.353057-0.353057j],
range(64)), common.CONST_DTYPE)
## for test
#QAM64 = QAM64[(7,3,24,56,35,39,60,28),]
#QAM64['symbols'] = [1, 0, 2, 6, 4, 5, 7, 3]
## ---- constellation indices ---------------------------------------------------
MODE_BPSK = 0
MODE_QPSK = 1
MODE_8PSK = 2
MODE_16QAM = 3
MODE_32QAM = 4
MODE_64QAM = 5
## ---- data scrambler -----------------------------------------------------------
class ScrambleData(object):
"""data scrambling sequence generator"""
def __init__(self):
self.reset()
def reset(self):
self._state = np.array([0,0,0,0,0,0,0,0,1], dtype=np.bool)
self._taps = np.array([0,0,0,0,1,0,0,0,1], dtype=np.bool)
def next(self, num_bits):
r = np.packbits(self._state[1:])[0]&((1<<num_bits)-1)
for _ in range(num_bits):
self._advance()
return r
def _advance(self):
self._state = np.concatenate(([self._state.dot(self._taps)&1],
self._state[0:-1]))
## ---- preamble definitions ---------------------------------------------------
## 184 = 8*23
PREAMBLE=common.n_psk(8, np.array(
[1,5,1,3,6,1,3,1,1,6,3,7,7,3,5,4,3,6,6,4,5,4,0,
2,2,2,6,0,7,5,7,4,0,7,5,7,1,6,1,0,5,2,2,6,2,3,
6,0,0,5,1,4,2,2,2,3,4,0,6,2,7,4,3,3,7,2,0,2,6,
4,4,1,7,6,2,0,6,2,3,6,7,4,3,6,1,3,7,4,6,5,7,2,
0,1,1,1,4,4,0,0,5,7,7,4,7,3,5,4,1,6,5,6,6,4,6,
3,4,3,0,7,1,3,4,7,0,1,4,3,3,3,5,1,1,1,4,6,1,0,
6,0,1,3,1,4,1,7,7,6,3,0,0,7,2,7,2,0,2,6,1,1,1,
2,7,7,5,3,3,6,0,5,3,3,1,0,7,1,1,0,3,0,4,0,7,3]))
## 103 = 31 + 1 + 3*13 + 1 + 31
REINSERTED_PREAMBLE=common.n_psk(8, np.array(
[0,0,0,0,0,2,4,6,0,4,0,4,0,6,4,2,0,0,0,0,0,2,4,6,0,4,0,4,0,6,4, ## MP+
2,
0,4,0,4,0,0,4,4,0,0,0,0,0, # + D0
0,4,0,4,0,0,4,4,0,0,0,0,0, # + D1
0,4,0,4,0,0,4,4,0,0,0,0,0, # + D2
6,
4,4,4,4,4,6,0,2,4,0,4,0,4,2,0,6,4,4,4,4,4,6,0,2,4,0,4,0,4,2,0])) ## MP-
## length 31 mini-probes
MINI_PROBE=[common.n_psk(8, np.array([0,0,0,0,0,2,4,6,0,4,0,4,0,6,4,2,0,0,0,0,0,2,4,6,0,4,0,4,0,6,4])), ## sign = + (0)
common.n_psk(8, np.array([4,4,4,4,4,6,0,2,4,0,4,0,4,2,0,6,4,4,4,4,4,6,0,2,4,0,4,0,4,2,0]))] ## sign = - (1)
## ---- di-bits ----------------------------------------------------------------
TO_DIBIT=[(0,0),(0,1),(1,1),(1,0)]
## ---- rate -------------------------------------------------------------------
TO_RATE={(0,0,0): {'baud': '--------', 'bits_per_symbol': 0}, ## reserved
(0,0,1): {'baud': '3200 bps', 'bits_per_symbol': 2, 'ci': MODE_QPSK},
(0,1,0): {'baud': '4800 bps', 'bits_per_symbol': 3, 'ci': MODE_8PSK},
(0,1,1): {'baud': '6400 bps', 'bits_per_symbol': 4, 'ci': MODE_16QAM},
(1,0,0): {'baud': '8000 bps', 'bits_per_symbol': 5, 'ci': MODE_32QAM},
(1,0,1): {'baud': '9600 bps', 'bits_per_symbol': 6, 'ci': MODE_64QAM},
(1,1,0): {'baud':'12800 bps', 'bits_per_symbol': 6, 'ci': MODE_64QAM},
(1,1,1): {'baud': '--------', 'bits_per_symbol': 0}} ## reserved
## ---- interleaver ------------------------------------------------------------
TO_INTERLEAVER={(0,0,0): {'frames': -1, 'id': '--', 'name': 'illegal'},
(0,0,1): {'frames': 1, 'id': 'US', 'name': 'Ultra Short'},
(0,1,0): {'frames': 3, 'id': 'VS', 'name': 'Very Short'},
(0,1,1): {'frames': 9, 'id': 'S', 'name': 'Short'},
(1,0,0): {'frames': 18, 'id': 'M', 'name': 'Medium'},
(1,0,1): {'frames': 36, 'id': 'L', 'name': 'Long'},
(1,1,0): {'frames': 72, 'id': 'VL', 'name': 'Very Long'},
(1,1,1): {'frames': -1, 'id': '--', 'name': 'illegal'}}
MP_COUNTER=[(0,0,1), ## 1st
(0,1,0), ## 2nd
(0,1,1), ## 3rd
(1,0,0)] ## 4th
## ---- interleaver size
INTL_SIZE = { ## 1 3 9 18 36 72
'--------': {'US': 0, 'VS': 0, 'S': 0, 'M': 0, 'L': 0, 'VL': 0},
'3200 bps': {'US': 512, 'VS': 1536, 'S': 4608, 'M': 9216, 'L': 18432, 'VL': 36864},
'4800 bps': {'US': 768, 'VS': 2304, 'S': 6912, 'M': 13824, 'L': 27648, 'VL': 55296},
'6400 bps': {'US': 1024, 'VS': 3072, 'S': 9216, 'M': 18432, 'L': 36864, 'VL': 73728},
'8000 bps': {'US': 1280, 'VS': 3840, 'S': 11520, 'M': 23040, 'L': 46080, 'VL': 92160},
'9600 bps': {'US': 1536, 'VS': 4608, 'S': 13824, 'M': 27648, 'L': 55296, 'VL': 110592}
}
## ---- interleaver increment
INTL_INCR = { ## 1 3 9 18 36 72
'--------': {'US': 0, 'VS': 0, 'S': 0, 'M': 0, 'L': 0, 'VL': 0},
'3200 bps': {'US': 97, 'VS': 229, 'S': 805, 'M': 1393, 'L': 3281, 'VL': 6985},
'4800 bps': {'US': 145, 'VS': 361, 'S': 1045, 'M': 2089, 'L': 5137, 'VL': 10273},
'6400 bps': {'US': 189, 'VS': 481, 'S': 1393, 'M': 3281, 'L': 6985, 'VL': 11141},
'8000 bps': {'US': 201, 'VS': 601, 'S': 1741, 'M': 3481, 'L': 8561, 'VL': 14441},
'9600 bps': {'US': 229, 'VS': 805, 'S': 2089, 'M': 5137, 'L': 10273, 'VL': 17329}
}
## ---- deinterleaver+depuncturer
class DeIntl_DePunct(object):
"""deinterleave"""
def __init__(self, size, incr):
self._size = size
self._i = 0
self._array = np.zeros(size, dtype=np.float64)
self._idx = np.mod(incr*np.arange(size, dtype=np.int32), size)
print('deinterleaver: ', size, incr, self._idx[0:100])
def fetch(self, a):
pass
def load(self, a):
n = len(a)
i = self._i
if i==0:
self._array[:] = 0
print('deinterleaver load buffer:', i,len(self._array),n)
assert(i+n <= self._size)
self._array[i:i+n] = a
self._i += n
result = np.zeros(0, dtype=np.float64)
if self._i == self._size:
print('deinterleaver: ', self._idx[0:100])
print('==== TEST ====', self._array)
#tmp = np.zeros(self._size, dtype=np.float32)
tmp = self._array[self._idx]
result = np.zeros(self._size*6//4, dtype=np.float64)
assert(len(result[0::6]) == len(tmp[0::4]))
assert(len(result[1::6]) == len(tmp[1::4]))
assert(len(result[2::6]) == len(tmp[2::4]))
assert(len(result[5::6]) == len(tmp[3::4]))
result[0::6] = tmp[0::4]
result[1::6] = tmp[1::4]
result[2::6] = tmp[2::4]
result[3::6] = 0
result[4::6] = 0
result[5::6] = tmp[3::4]
print('==================== interleaver is full! ====================',
len(result[0::6]), len(tmp[0::4]), np.sum(result==0))
self._i = 0
return result
## ---- physcal layer class -----------------------------------------------------
class PhysicalLayer(object):
"""Physical layer description for MIL-STD-188-110 Appendix C = STANAG 4539"""
def __init__(self, sps):
"""intialization"""
self._sps = sps
self._frame_counter = -2
self._constellations = [BPSK, QPSK, PSK8, QAM16, QAM32, QAM64]
self._preamble = self.get_preamble()
self._scramble = ScrambleData()
self._viterbi_decoder = viterbi27(0x6d, 0x4f)
def get_constellations(self):
return self._constellations
def get_next_frame(self, symbols):
"""returns a tuple describing the frame:
[0] ... known+unknown symbols and scrambling
[1] ... modulation type after descrambling
[2] ... a boolean indicating if the processing should continue
[3] ... a boolean indicating if the soft decision for the unknown
symbols are saved"""
print('-------------------- get_frame --------------------', self._frame_counter)
success = True
if self._frame_counter == -2: ## ---- preamble
self._deintl_depunct = None
self._mode = {}
self._preamble_offset = 0
self._frame_counter += 1
return [self._preamble,MODE_BPSK,success,False]
if self._frame_counter == -1: ## --- re-inserted preamble
self._frame_counter += 1
success = self.get_preamble_quality(symbols) if self._frame_counter < 4 else self.get_data_frame_quality(symbols)
return [self.make_reinserted_preamble(self._preamble_offset,success),MODE_QPSK,success,False]
if self._frame_counter >= 0: ## ---- data frames
got_reinserted_preamble = self._frame_counter == 0
self._frame_counter += 1
if got_reinserted_preamble:
success = self.decode_reinserted_preamble(symbols)
else:
success = self.get_data_frame_quality(symbols)
return [self.make_data_frame(success),self._constellation_index,success,True]
def get_doppler(self, iq_samples):
"""quality check and doppler estimation for preamble"""
success,doppler = True,0
if len(iq_samples) != 0:
sps = self._sps
m = 23*sps
idx = np.arange(m)
idx2 = np.arange(m+23*sps)
_,zp = self.get_preamble_z()
n = len(zp)
cc = np.correlate(iq_samples, zp)
imax = np.argmax(np.abs(cc[0:23*sps]))
print('imax=', imax, len(iq_samples))
pks = [np.correlate(iq_samples[imax+i*m+idx],
zp[i*m+idx])[0]
for i in range(n//m)]
val = [np.mean(np.abs(np.correlate(iq_samples[imax+i*m+idx2],
zp[i*m+idx])[11*sps+np.arange(-2*sps,2*sps)]))
for i in range((n//m)-1)]
tests = np.abs(pks[0:-1])/val
success = np.median(tests) > 2.0
print('test:', np.abs(pks), tests)
if success:
print('doppler apks', np.abs(pks))
print('doppler ppks', np.angle(pks),
np.diff(np.unwrap(np.angle(pks)))/m,
np.mean(np.diff(np.unwrap(np.angle(pks)))/m))
doppler = common.freq_est(pks)/m;
print('success=', success, 'doppler=', doppler)
return success,doppler
def set_mode(self, mode):
pass
def get_preamble_quality(self, symbols):
print('get_preamble_quality', np.abs(np.mean(symbols[-32:])), symbols[-32:])
return np.abs(np.mean(symbols[-32:])) > 0.5
def get_data_frame_quality(self, symbols):
print('get_data_frame_quality', np.mean(symbols[-31:]))
return np.abs(np.mean(symbols[-31:])) > 0.5
def decode_reinserted_preamble(self, symbols):
## decode D0,D1,D2
success = True
z = np.array([np.mean(symbols[-71+i*13:-71+(i+1)*13]) for i in range(3)])
if np.mean(np.abs(z)) < 0.4:
return False
print('decode_reinserted_preamble',
'\nHH', symbols[0:-71],
'\nD0', symbols[-71 :-71+13],
'\nD1', symbols[-71+13:-71+26],
'\nD2', symbols[-71+26:-71+39],
'\nTT', symbols[-71+4*13:], z)
d0d1d2 = map(np.uint8, np.mod(np.round(np.angle(z)/np.pi*2),4))
dibits = [TO_DIBIT[idx] for idx in d0d1d2]
mode = {'rate': tuple([x[0] for x in dibits]),
'interleaver': tuple([x[1] for x in dibits])}
if self._mode != {}:
success = (mode == self._mode)
if not success:
return success
self._mode = mode
self._rate_info = rate_info = TO_RATE[self._mode['rate']]
self._intl_info = intl_info = TO_INTERLEAVER[self._mode['interleaver']]
print('======== rate,interleaver:', rate_info, intl_info)
self._interleaver_frames = intl_info['frames']
baud = rate_info['baud']
intl_id = intl_info['id']
intl_size = INTL_SIZE[baud][intl_id]
intl_incr = INTL_INCR[baud][intl_id]
if self._deintl_depunct == None:
self._deintl_depunct = DeIntl_DePunct(size=intl_size,
incr=intl_incr)
self._constellation_index = rate_info['ci']
print('constellation index', self._constellation_index)
self._scramble.reset()
num_bits = max(3, rate_info['bits_per_symbol'])
iscr = np.array([self._scramble.next(num_bits) for _ in range(256)],
dtype=np.uint8)
print('iscr=', iscr)
self._data_scramble = np.ones (256, dtype=np.complex64)
self._data_scramble_xor = np.zeros(256, dtype=np.uint8)
if rate_info['ci'] > MODE_8PSK:
self._data_scramble_xor = iscr
else:
self._data_scramble = common.n_psk(8, iscr)
return success
def make_reinserted_preamble(self, offset, success):
""" offset= 0 -> 1st reinsesrted preamble
offset=-72 -> all following reinserted preambles"""
a = common.make_scr(REINSERTED_PREAMBLE[offset:], REINSERTED_PREAMBLE[offset:])
a['symb'][-71:-71+3*13] = 0 ## D0,D1,D2
print('make_reinserted_preamble', offset, success, len(a['symb']))
if not success:
self._frame_counter = -2
return a
def make_data_frame(self, success):
self._preamble_offset = -72 ## all following reinserted preambles start at index -72
a = np.zeros(256+31, common.SYMB_SCRAMBLE_DTYPE)
a['scramble'][:256] = self._data_scramble
a['scramble_xor'][:256] = self._data_scramble_xor
n = (self._frame_counter-1)%72
if self._frame_counter == 72:
self._frame_counter = -1
m = n%18
if m == 0:
cnt = n//18
self._mp = (1,1,1,1,1,1,1,0)+self._mode['rate']+self._mode['interleaver']+MP_COUNTER[cnt]+(0,)
print('new mini-probe signs n=',n,'m=',m, 'cnt=',cnt, self._mp)
print('make_data_frame', m, self._mp[m])
a['symb'][256:] = MINI_PROBE[self._mp[m]]
a['scramble'][256:] = MINI_PROBE[self._mp[m]]
if not success:
self._frame_counter = -2
return a
def decode_soft_dec(self, soft_dec):
r = self._deintl_depunct.load(soft_dec)
if r.shape[0] == 0:
return []
self._viterbi_decoder.reset()
decoded_bits = np.roll(self._viterbi_decoder.udpate(r), 7)
print('bits=', decoded_bits[:100])
print('quality={}% ({},{})'.format(120.0*self._viterbi_decoder.quality()/(2*len(decoded_bits)),
self._viterbi_decoder.quality(),
len(decoded_bits)))
return decoded_bits
@staticmethod
def get_preamble():
"""preamble symbols + scrambler"""
return common.make_scr(PREAMBLE, PREAMBLE)
def get_preamble_z(self):
"""preamble symbols for preamble correlation"""
return 2,np.array([z for z in PREAMBLE for _ in range(self._sps)])
if __name__ == '__main__':
print(PREAMBLE)
z = common.n_psk(8,PREAMBLE)
cc = [np.sum(z[0:23]*np.conj(z[23*i:23*i+23])) for i in range(6)]
print(np.abs(cc))
print(np.angle(cc)/np.pi*4)
print(all(z==PhysicalLayer.get_preamble()['symb']))
print(len(PhysicalLayer.get_preamble()['symb']))
s = ScrambleData()
print([s.next(1) for _ in range(511)])
print([s.next(1) for _ in range(511)] ==
[s.next(1) for _ in range(511)])
#print(QAM64)
#print(QAM32)
#print(QAM16)
#print(PSK8)
#print(QPSK)
#print(BPSK)
#print(MINI_PROBE_PLUS)
#print(MINI_PROBE_MINUS)
#print(MINI_PROBE_PLUS*MINI_PROBE_MINUS)
#for i in range(len(QAM64)):
# print(QAM64['points'][i])
print([s.next(6) for _ in range(256)])