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fix packet detection

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This commit is contained in:
Jinghao Shi 2017-04-14 11:01:05 -04:00
parent 701cbb70c9
commit bcee4f66a1
1 changed files with 8 additions and 8 deletions
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16
scripts/decode.py
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@ -225,13 +225,13 @@ class ChannelEstimator(object):
prod_sum += prod
beta = cmath.phase(prod_sum)
print "[PILOT OFFSET] %f (%d)" % (beta, int(beta*PHASE_SCALE))
# beta = 0
carriers = []
for c in self.subcarriers:
if c in PILOT_SUBCARRIES:
continue
symbol[c] *= cmath.exp(complex(0, beta))
carriers.append(symbol[c] / self.gain[c])
symbol[c] /= self.gain[c]
carriers.append(symbol[c])
return carriers
def switch_ht(self):
@ -280,7 +280,7 @@ class ChannelEstimator(object):
fine_offset = cmath.phase(sum([lts[i]*lts[i+64].conjugate()
for i in range(len(lts)-64)]))/64
print '[FINE OFFSET] %f (%d)' % (fine_offset, int(fine_offset*PHASE_SCALE))
# fine_offset = 0
fine_offset = 0
self.lts_samples = [c*cmath.exp(complex(0, n*fine_offset))
for n, c in enumerate(lts)]
@ -460,11 +460,11 @@ class Decoder(object):
Returns the index of the first sample of STS
None if no packet was detected.
"""
lts = LONG_PREAMBLE[64:64+64]
peaks = np.array([abs(c) for c in np.convolve(
samples, lts, mode='same')]).argsort()[-2:]
if (max(peaks) - min(peaks) == 64) and (min(peaks) - 33 - 160) > 0:
return min(peaks) - 33 - 160
lts = LONG_PREAMBLE[-64:]
peaks = np.array([abs(c) for c in np.correlate(
samples, lts, mode='valid')]).argsort()[-2:]
if (max(peaks) - min(peaks) == 64) and (min(peaks) - 32 - 160) > 0:
return min(peaks) - 32 - 160
else:
return None