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added support for 75 bps orthogonal WALSH modulation

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This commit is contained in:
cmayer 2019-05-13 09:51:19 +02:00
parent 976526913d
commit be43965a90
1 changed files with 62 additions and 32 deletions
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70
python/physical_layer/MIL_STD_188_110A.py
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@ -5,8 +5,8 @@ import numpy as np
import common import common
from digitalhf.digitalhf_swig import viterbi27 from digitalhf.digitalhf_swig import viterbi27
## ---- Walsh-4 codes ----------------------------------------------------------- ## ---- Walsh-8 codes -----------------------------------------------------------
WALSH = np.array([[0,0,0,0, 0,0,0,0], # 0 - 000 WALSH8 = np.array([[0,0,0,0, 0,0,0,0], # 0 - 000
[0,1,0,1, 0,1,0,1], # 1 - 001 [0,1,0,1, 0,1,0,1], # 1 - 001
[0,0,1,1, 0,0,1,1], # 2 - 010 [0,0,1,1, 0,0,1,1], # 2 - 010
[0,1,1,0, 0,1,1,0], # 3 - 011 [0,1,1,0, 0,1,1,0], # 3 - 011
@ -16,14 +16,25 @@ WALSH = np.array([[0,0,0,0, 0,0,0,0], # 0 - 000
[0,1,1,0, 1,0,0,1]], # 7 - 111 [0,1,1,0, 1,0,0,1]], # 7 - 111
dtype=np.uint8) dtype=np.uint8)
FROM_WALSH = -np.ones(256, dtype=np.int8) FROM_WALSH8 = -np.ones(256, dtype=np.int8)
for i in range(8): for i in range(8):
FROM_WALSH[np.packbits(WALSH[i][:])[0]] = i FROM_WALSH8[np.packbits(WALSH8[i][:])[0]] = i
## ---- Walsh-4 codes -----------------------------------------------------------
WALSH4 = np.array([[0,0,0,0], # 0 - 00
[0,1,0,1], # 1 - 01
[0,1,1,0], # 3 - 11 modified gray coding!
[0,0,1,1]], # 2 - 10 modified gray coding!
dtype=np.uint8)
FROM_WALSH4 = -np.ones(256, dtype=np.int8)
for i in range(4):
FROM_WALSH4[np.packbits(WALSH4[i][:])[0]] = i
## ---- tri-bit codes ----------------------------------------------------------- ## ---- tri-bit codes -----------------------------------------------------------
TRIBIT = np.zeros((8,32), dtype=np.uint8) TRIBIT = np.zeros((8,32), dtype=np.uint8)
for i in range(8): for i in range(8):
TRIBIT[i][:] = np.concatenate([WALSH[i][:] for j in range(4)]) TRIBIT[i][:] = np.concatenate([WALSH8[i][:] for j in range(4)])
## ---- tri-bit scramble sequence for preamble ---------------------------------- ## ---- tri-bit scramble sequence for preamble ----------------------------------
TRIBIT_SCRAMBLE = np.array( TRIBIT_SCRAMBLE = np.array(
@ -93,9 +104,9 @@ MODE[4][7] = {'bit_rate': 300, 'ci':MODE_BPSK, 'interleaver':['L', 40,144], 'unk
MODE[7][4] = {'bit_rate': 150, 'ci':MODE_BPSK, 'interleaver':['S', 40, 18], 'unknown':20,'known':20, 'nsymb': 1, 'coding_rate': '1/8', 'repeat': 4} MODE[7][4] = {'bit_rate': 150, 'ci':MODE_BPSK, 'interleaver':['S', 40, 18], 'unknown':20,'known':20, 'nsymb': 1, 'coding_rate': '1/8', 'repeat': 4}
MODE[5][4] = {'bit_rate': 150, 'ci':MODE_BPSK, 'interleaver':['L', 40,144], 'unknown':20,'known':20, 'nsymb': 1, 'coding_rate': '1/8', 'repeat': 4} MODE[5][4] = {'bit_rate': 150, 'ci':MODE_BPSK, 'interleaver':['L', 40,144], 'unknown':20,'known':20, 'nsymb': 1, 'coding_rate': '1/8', 'repeat': 4}
## 75 bps othogonal WALSH modulation
MODE[7][5] = {'bit_rate': 75, 'ci':MODE_QPSK, 'interleaver':['S', 10, 9], 'unknown':-1,'known': 0, 'nsymb':32, 'coding_rate': '1/2', 'repeat': 1} MODE[7][5] = {'bit_rate': 75, 'ci':MODE_BPSK, 'interleaver':['S', 10, 9], 'unknown':160,'known': 0, 'nsymb':32, 'coding_rate': '1/2', 'repeat': 1}
MODE[5][4] = {'bit_rate': 75, 'ci':MODE_QPSK, 'interleaver':['L', 20, 36], 'unknown':-1,'known': 0, 'nsymb':32, 'coding_rate': '1/2', 'repeat': 1} MODE[5][5] = {'bit_rate': 75, 'ci':MODE_BPSK, 'interleaver':['L', 20, 36], 'unknown':160,'known': 0, 'nsymb':32, 'coding_rate': '1/2', 'repeat': 1}
## ---- deinterleaver ----------------------------------------------------------- ## ---- deinterleaver -----------------------------------------------------------
@ -174,7 +185,12 @@ class PhysicalLayer(object):
else: ## data mode else: ## data mode
self._frame_counter += 1 self._frame_counter += 1
##print('test:', symbols[self._mode['unknown']:], np.mean(np.real(symbols[self._mode['unknown']:]))) ##print('test:', symbols[self._mode['unknown']:], np.mean(np.real(symbols[self._mode['unknown']:])))
if self._frame_counter < self._num_frames_per_block-2: if self._mode['known'] == 0: ## orthogonal WALSH modulation
success = True
for i in range(5):
a = symbols[32*i:32*(i+1)]
success &= np.max(np.imag(np.mean(a.reshape(8,4),0))) < 0.25
elif self._frame_counter < self._num_frames_per_block-2:
success = np.mean(np.real(symbols[self._mode['unknown']:])) > 0.7 success = np.mean(np.real(symbols[self._mode['unknown']:])) > 0.7
return [self.get_next_data_frame(success),self._mode['ci'],success,success] return [self.get_next_data_frame(success),self._mode['ci'],success,success]
@ -188,10 +204,10 @@ class PhysicalLayer(object):
common.SYMB_SCRAMBLE_DTYPE) common.SYMB_SCRAMBLE_DTYPE)
n_unknown = self._mode['unknown'] n_unknown = self._mode['unknown']
a['symb'][0:n_unknown] = 0 a['symb'][0:n_unknown] = 0
if self._frame_counter >= self._num_frames_per_block-2: if self._mode['known'] != 0 and self._frame_counter >= self._num_frames_per_block-2:
idx_d1d2 = self._frame_counter - self._num_frames_per_block + 2; idx_d1d2 = self._frame_counter - self._num_frames_per_block + 2;
a['symb'][n_unknown :n_unknown+ 8] *= common.n_psk(2, WALSH[self._d1d2[idx_d1d2]][:]) a['symb'][n_unknown :n_unknown+ 8] *= common.n_psk(2, WALSH8[self._d1d2[idx_d1d2]][:])
a['symb'][n_unknown+8:n_unknown+16] *= common.n_psk(2, WALSH[self._d1d2[idx_d1d2]][:]) a['symb'][n_unknown+8:n_unknown+16] *= common.n_psk(2, WALSH8[self._d1d2[idx_d1d2]][:])
if not success: if not success:
self._frame_counter = -1 self._frame_counter = -1
self._pre_counter = -1 self._pre_counter = -1
@ -226,7 +242,7 @@ class PhysicalLayer(object):
return success,doppler return success,doppler
def decode_preamble(self, symbols): def decode_preamble(self, symbols):
data = [FROM_WALSH[np.packbits data = [FROM_WALSH8[np.packbits
(np.real (np.real
(np.sum (np.sum
(symbols[i:i+32].reshape((4,8)),0))<0)[0]] (symbols[i:i+32].reshape((4,8)),0))<0)[0]]
@ -237,7 +253,10 @@ class PhysicalLayer(object):
self._mode = mode = MODE[data[9]][data[10]] self._mode = mode = MODE[data[9]][data[10]]
self._block_len = 11520 if mode['interleaver'][0] == 'L' else 1440 self._block_len = 11520 if mode['interleaver'][0] == 'L' else 1440
self._frame_len = mode['known'] + mode['unknown'] self._frame_len = mode['known'] + mode['unknown']
self._num_frames_per_block = self._block_len/self._frame_len; if mode['known'] == 0: ## orthogonal WALSH modulation
self._num_frames_per_block = mode['interleaver'][1]*mode['interleaver'][2]/2*32/160
else:
self._num_frames_per_block = self._block_len/self._frame_len
self._deinterleaver = Deinterleaver(mode['interleaver'][1], mode['interleaver'][2]) self._deinterleaver = Deinterleaver(mode['interleaver'][1], mode['interleaver'][2])
self._depuncturer = common.Depuncturer(repeat=mode['repeat']) self._depuncturer = common.Depuncturer(repeat=mode['repeat'])
self._viterbi_decoder = viterbi27(0x6d, 0x4f) self._viterbi_decoder = viterbi27(0x6d, 0x4f)
@ -249,13 +268,24 @@ class PhysicalLayer(object):
def decode_soft_dec(self, soft_dec): def decode_soft_dec(self, soft_dec):
print('decode_soft_dec', len(soft_dec), soft_dec.dtype) print('decode_soft_dec', len(soft_dec), soft_dec.dtype)
if self._mode['known'] == 0: ## orthogonal WALSH modulation
n = len(soft_dec) // 32
soft_bits = np.zeros(2*n, dtype=np.float32)
for i in range(n):
w = np.sum(soft_dec[32*i:32*(i+1)].reshape(4,8),0)
b = FROM_WALSH4[np.packbits(w[0:4]>0)[0]]
print('WALSH', i, w, b)
abs_soft_dec = np.mean(np.abs(w))
soft_bits[2*i] = abs_soft_dec*(2*(b>>1)-1)
soft_bits[2*i+1] = abs_soft_dec*(2*(b &1)-1)
print('WALSH soft_bits=', soft_bits)
r = self._deinterleaver.load(soft_bits)
else:
r = self._deinterleaver.load(soft_dec) r = self._deinterleaver.load(soft_dec)
print('decode_soft_dec r=', r.shape) print('decode_soft_dec r=', r.shape)
if r.shape[0] == 0: if r.shape[0] == 0:
return [] return []
##for i in range(r.shape[0]//4): print('deinterleaved bits: ', r>0)
## print('BB:', r[4*i]<0, r[4*i+2]<0, '|', r[4*i+1]<0, r[4*i+3]<0)
rd = self._depuncturer.process(r) rd = self._depuncturer.process(r)
self._viterbi_decoder.reset() self._viterbi_decoder.reset()
decoded_bits = self._viterbi_decoder.udpate(rd) decoded_bits = self._viterbi_decoder.udpate(rd)
@ -301,9 +331,9 @@ if __name__ == '__main__':
print(i, all(z[32*sps*i:32*sps*(i+1)] == z[32*sps*(3+i):32*sps*(3+i+1)])) print(i, all(z[32*sps*i:32*sps*(i+1)] == z[32*sps*(3+i):32*sps*(3+i+1)]))
#print(np.sum(np.sum(z[0:32*5] * np.conj(z[32*5*3:32*5*4])))) #print(np.sum(np.sum(z[0:32*5] * np.conj(z[32*5*3:32*5*4]))))
#print(WALSH[1][:]) #print(WALSH8[1][:])
#print(sum(WALSH[1][:]*(1<<np.array(range(7,-1,-1))))) #print(sum(WALSH8[1][:]*(1<<np.array(range(7,-1,-1)))))
#print(FROM_WALSH) #print(FROM_WALSH8)
#print(gen_data_scramble()) #print(gen_data_scramble())
s=ScrambleData() s=ScrambleData()