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sigProcLib: Abstract out common part of Normal/RACH burst detection.
As a side change - get rid of passing toa and amp arguments as pointers and use references instead. The commit doesn't change behaviour, but makes the code cleaner. Signed-off-by: Tom Tsou <tom.tsou@ettus.com>
This commit is contained in:
Alexander Chemeris
committed by
Tom Tsou
Tom Tsou
parent
72e8619632
commit
130a8007fa
@@ -1386,26 +1386,25 @@ static float maxAmplitude(signalVector &burst)
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return max;
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}
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/*
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* RACH burst detection
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/*
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* RACH/Normal burst detection with clipping detection
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*
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* Correlation window parameters:
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* target: Tail bits + RACH length (reduced from 41 to a multiple of 4)
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* head: Search 4 symbols before target
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* tail: Search 10 symbols after target
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* target: Tail bits + burst length
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* head: Search symbols before target
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* tail: Search symbols after target
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*/
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int detectRACHBurst(signalVector &rxBurst,
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float thresh,
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int sps,
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complex *amp,
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float *toa)
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int detectGeneralBurst(signalVector &rxBurst,
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float thresh,
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int sps,
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complex &,
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float &toa,
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int target, int head, int tail,
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CorrelationSequence *sync)
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{
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int rc, start, target, head, tail, len;
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int rc, start, len;
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bool clipping = false;
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float _toa;
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complex _amp;
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signalVector *corr;
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CorrelationSequence *sync;
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if ((sps != 1) && (sps != 4))
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return -SIGERR_UNSUPPORTED;
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@@ -1419,38 +1418,57 @@ int detectRACHBurst(signalVector &rxBurst,
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clipping = true;
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}
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target = 8 + 40;
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head = 4;
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tail = 10;
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start = (target - head) * sps - 1;
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len = (head + tail) * sps;
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sync = gRACHSequence;
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corr = new signalVector(len);
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rc = detectBurst(rxBurst, *corr, sync,
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thresh, sps, &_amp, &_toa, start, len);
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thresh, sps, &, &toa, start, len);
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delete corr;
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if (rc < 0) {
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return -SIGERR_INTERNAL;
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} else if (!rc) {
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if (amp)
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*amp = 0.0f;
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if (toa)
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*toa = 0.0f;
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amp = 0.0f;
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toa = 0.0f;
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return clipping?-SIGERR_CLIP:SIGERR_NONE;
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}
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/* Subtract forward search bits from delay */
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if (toa)
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*toa = _toa - head * sps;
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if (amp)
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*amp = _amp;
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toa -= head * sps;
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return 1;
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}
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/*
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* RACH burst detection
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*
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* Correlation window parameters:
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* target: Tail bits + RACH length (reduced from 41 to a multiple of 4)
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* head: Search 4 symbols before target
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* tail: Search 10 symbols after target
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*/
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int detectRACHBurst(signalVector &rxBurst,
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float thresh,
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int sps,
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complex &,
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float &toa)
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{
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int rc, target, head, tail;
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CorrelationSequence *sync;
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target = 8 + 40;
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head = 4;
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tail = 10;
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sync = gRACHSequence;
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rc = detectGeneralBurst(rxBurst, thresh, sps, amp, toa,
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target, head, tail, sync);
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return rc;
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}
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/*
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* Normal burst detection
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*
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@@ -1460,67 +1478,32 @@ int detectRACHBurst(signalVector &rxBurst,
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* tail: Search 4 symbols + maximum expected delay
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*/
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int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh,
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int sps, complex *amp, float *toa, unsigned max_toa,
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int sps, complex &, float &toa, unsigned max_toa,
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bool chan_req, signalVector **chan, float *chan_offset)
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{
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int rc, start, target, head, tail, len;
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bool clipping = false;
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complex _amp;
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float _toa;
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signalVector *corr;
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int rc, target, head, tail;
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CorrelationSequence *sync;
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if ((tsc < 0) || (tsc > 7) || ((sps != 1) && (sps != 4)))
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if ((tsc < 0) || (tsc > 7))
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return -SIGERR_UNSUPPORTED;
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// Detect potential clipping
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// We still may be able to demod the burst, so we'll give it a try
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// and only report clipping if we can't demod.
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float maxAmpl = maxAmplitude(rxBurst);
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if (maxAmpl > CLIP_THRESH) {
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LOG(DEBUG) << "max burst amplitude: " << maxAmpl << " is above the clipping threshold: " << CLIP_THRESH << std::endl;
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clipping = true;
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}
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target = 3 + 58 + 16 + 5;
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head = 4;
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tail = 4 + max_toa;
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start = (target - head) * sps - 1;
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len = (head + tail) * sps;
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sync = gMidambles[tsc];
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corr = new signalVector(len);
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rc = detectBurst(rxBurst, *corr, sync,
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thresh, sps, &_amp, &_toa, start, len);
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delete corr;
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if (rc < 0) {
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return -SIGERR_INTERNAL;
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} else if (!rc) {
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if (amp)
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*amp = 0.0f;
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if (toa)
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*toa = 0.0f;
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return clipping?-SIGERR_CLIP:SIGERR_NONE;
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}
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/* Subtract forward search bits from delay */
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_toa -= head * sps;
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if (toa)
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*toa = _toa;
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if (amp)
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*amp = _amp;
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rc = detectGeneralBurst(rxBurst, thresh, sps, amp, toa,
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target, head, tail, sync);
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/* Equalization not currently supported */
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if (chan_req) {
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if (rc > 0 && chan_req) {
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*chan = new signalVector(6 * sps);
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if (chan_offset)
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*chan_offset = 0.0;
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}
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return 1;
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return rc;
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}
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signalVector *decimateVector(signalVector &wVector, size_t factor)
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