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-rw-r--r--Transceiver52M/Transceiver.cpp33
-rw-r--r--Transceiver52M/Transceiver.h12
-rw-r--r--Transceiver52M/sigProcLib.cpp46
3 files changed, 55 insertions, 36 deletions
diff --git a/Transceiver52M/Transceiver.cpp b/Transceiver52M/Transceiver.cpp
index ea608b1..21aaabf 100644
--- a/Transceiver52M/Transceiver.cpp
+++ b/Transceiver52M/Transceiver.cpp
@@ -534,9 +534,9 @@ Transceiver::CorrType Transceiver::expectedCorrType(GSM::Time currTime,
* Detect RACH synchronization sequence within a burst. No equalization
* is used or available on the RACH channel.
*/
-bool Transceiver::detectRACH(TransceiverState *state,
- signalVector &burst,
- complex &amp, float &toa)
+int Transceiver::detectRACH(TransceiverState *state,
+ signalVector &burst,
+ complex &amp, float &toa)
{
float threshold = 6.0;
@@ -548,9 +548,10 @@ bool Transceiver::detectRACH(TransceiverState *state,
* state information and channel estimate if necessary. Equalization
* is currently disabled.
*/
-bool Transceiver::detectTSC(TransceiverState *state, signalVector &burst,
- complex &amp, float &toa, GSM::Time &time)
+int Transceiver::detectTSC(TransceiverState *state, signalVector &burst,
+ complex &amp, float &toa, GSM::Time &time)
{
+ int success;
int tn = time.TN();
float chanOffset, threshold = 5.0;
bool noise, needDFE = false, estimateChan = false;
@@ -568,10 +569,11 @@ bool Transceiver::detectTSC(TransceiverState *state, signalVector &burst,
}
/* Detect normal burst midambles */
- if (!analyzeTrafficBurst(burst, mTSC, threshold, mSPSRx, &amp,
- &toa, mMaxExpectedDelay, estimateChan,
- &chanResp, &chanOffset)) {
- return false;
+ success = analyzeTrafficBurst(burst, mTSC, threshold, mSPSRx, &amp,
+ &toa, mMaxExpectedDelay, estimateChan,
+ &chanResp, &chanOffset);
+ if (success <= 0) {
+ return success;
}
noise = state->mNoiseLev;
@@ -591,7 +593,7 @@ bool Transceiver::detectTSC(TransceiverState *state, signalVector &burst,
state->chanEstimateTime[tn] = time;
}
- return true;;
+ return 1;
}
/*
@@ -622,7 +624,8 @@ SoftVector *Transceiver::pullRadioVector(GSM::Time &wTime, double &RSSI,
double &timingOffset, double &noise,
size_t chan)
{
- bool success, equalize = false;
+ int success;
+ bool equalize = false;
complex amp;
float toa, pow, max = -1.0, avg = 0.0;
int max_i = -1;
@@ -673,12 +676,12 @@ SoftVector *Transceiver::pullRadioVector(GSM::Time &wTime, double &RSSI,
/* Update noise average if no bust detected or alert on error */
if (success <= 0) {
- if (!success) {
+ if (success == SIGERR_NONE) {
state->mNoises.insert(avg);
} else if (success == -SIGERR_CLIP) {
- LOG(ALERT) << "Clipping detected on RACH input";
- } else if (success < 0) {
- LOG(ALERT) << "Unhandled RACH error";
+ LOG(WARNING) << "Clipping detected on received RACH or Normal Burst";
+ } else {
+ LOG(WARNING) << "Unhandled RACH or Normal Burst detection error";
}
delete radio_burst;
diff --git a/Transceiver52M/Transceiver.h b/Transceiver52M/Transceiver.h
index 1639d0d..a7b04ed 100644
--- a/Transceiver52M/Transceiver.h
+++ b/Transceiver52M/Transceiver.h
@@ -209,14 +209,14 @@ private:
void writeClockInterface(void);
/** Detect RACH bursts */
- bool detectRACH(TransceiverState *state,
- signalVector &burst,
- complex &amp, float &toa);
+ int detectRACH(TransceiverState *state,
+ signalVector &burst,
+ complex &amp, float &toa);
/** Detect normal bursts */
- bool detectTSC(TransceiverState *state,
- signalVector &burst,
- complex &amp, float &toa, GSM::Time &time);
+ int detectTSC(TransceiverState *state,
+ signalVector &burst,
+ complex &amp, float &toa, GSM::Time &time);
/** Demodulat burst and output soft bits */
SoftVector *demodulate(TransceiverState *state,
diff --git a/Transceiver52M/sigProcLib.cpp b/Transceiver52M/sigProcLib.cpp
index 9d8410b..42b4e6e 100644
--- a/Transceiver52M/sigProcLib.cpp
+++ b/Transceiver52M/sigProcLib.cpp
@@ -28,6 +28,7 @@
#include "sigProcLib.h"
#include "GSMCommon.h"
+#include "Logger.h"
extern "C" {
#include "convolve.h"
@@ -1372,16 +1373,17 @@ static int detectBurst(signalVector &burst,
return 1;
}
-static int detectClipping(signalVector &burst, float thresh)
+static float maxAmplitude(signalVector &burst)
{
- for (size_t i = 0; i < burst.size(); i++) {
- if (fabs(burst[i].real()) > thresh)
- return 1;
- if (fabs(burst[i].imag()) > thresh)
- return 1;
- }
-
- return 0;
+ float max = 0.0;
+ for (size_t i = 0; i < burst.size(); i++) {
+ if (fabs(burst[i].real()) > max)
+ max = fabs(burst[i].real());
+ if (fabs(burst[i].imag()) > max)
+ max = fabs(burst[i].imag());
+ }
+
+ return max;
}
/*
@@ -1399,6 +1401,7 @@ int detectRACHBurst(signalVector &rxBurst,
float *toa)
{
int rc, start, target, head, tail, len;
+ bool clipping = false;
float _toa;
complex _amp;
signalVector *corr;
@@ -1407,8 +1410,14 @@ int detectRACHBurst(signalVector &rxBurst,
if ((sps != 1) && (sps != 4))
return -SIGERR_UNSUPPORTED;
- if (detectClipping(rxBurst, CLIP_THRESH))
- return -SIGERR_CLIP;
+ // Detect potential clipping
+ // We still may be able to demod the burst, so we'll give it a try
+ // and only report clipping if we can't demod.
+ float maxAmpl = maxAmplitude(rxBurst);
+ if (maxAmpl > CLIP_THRESH) {
+ LOG(DEBUG) << "max burst amplitude: " << maxAmpl << " is above the clipping threshold: " << CLIP_THRESH << std::endl;
+ clipping = true;
+ }
target = 8 + 40;
head = 4;
@@ -1430,7 +1439,7 @@ int detectRACHBurst(signalVector &rxBurst,
*amp = 0.0f;
if (toa)
*toa = 0.0f;
- return 0;
+ return clipping?-SIGERR_CLIP:SIGERR_NONE;
}
/* Subtract forward search bits from delay */
@@ -1455,6 +1464,7 @@ int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh,
bool chan_req, signalVector **chan, float *chan_offset)
{
int rc, start, target, head, tail, len;
+ bool clipping = false;
complex _amp;
float _toa;
signalVector *corr;
@@ -1463,8 +1473,14 @@ int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh,
if ((tsc < 0) || (tsc > 7) || ((sps != 1) && (sps != 4)))
return -SIGERR_UNSUPPORTED;
- if (detectClipping(rxBurst, CLIP_THRESH))
- return -SIGERR_CLIP;
+ // Detect potential clipping
+ // We still may be able to demod the burst, so we'll give it a try
+ // and only report clipping if we can't demod.
+ float maxAmpl = maxAmplitude(rxBurst);
+ if (maxAmpl > CLIP_THRESH) {
+ LOG(DEBUG) << "max burst amplitude: " << maxAmpl << " is above the clipping threshold: " << CLIP_THRESH << std::endl;
+ clipping = true;
+ }
target = 3 + 58 + 16 + 5;
head = 4;
@@ -1486,7 +1502,7 @@ int analyzeTrafficBurst(signalVector &rxBurst, unsigned tsc, float thresh,
*amp = 0.0f;
if (toa)
*toa = 0.0f;
- return 0;
+ return clipping?-SIGERR_CLIP:SIGERR_NONE;
}
/* Subtract forward search bits from delay */
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-23 23:59:18 +0000