MMDVM/MMDVMHost
1
0
Fork 0
mirror of https://github.com/g4klx/MMDVMHost synced 2025-12-23 00:35:53 +08:00
Code Issues Packages Projects Releases Wiki Activity

Use the BER from the Viterbi decoder in M17 mode to determine if the

Browse Source 
audio is usable or not.
This commit is contained in:
Jonathan Naylor
2021-06-28 19:16:16 +01:00
parent f7b8448963
commit dae05ad58a
4 changed files with 72 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

119
M17Control.cpp
View File

@@ -79,6 +79,7 @@ m_rfErrs(0U),
m_rfBits(1U),
m_rfLSF(),
m_rfLSFn(0U),
m_rfFN(0U),
m_netLSF(),
m_netLSFn(0U),
m_rssiMapper(rssiMapper),
@@ -172,7 +173,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
CM17Convolution conv;
unsigned char frame[M17_LSF_LENGTH_BYTES];
conv.decodeLinkSetup(data + 2U + M17_SYNC_LENGTH_BYTES, frame);
unsigned int ber = conv.decodeLinkSetup(data + 2U + M17_SYNC_LENGTH_BYTES, frame);
bool valid = CM17CRC::checkCRC16(frame, M17_LSF_LENGTH_BYTES);
if (valid) {
@@ -184,15 +185,16 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
return false;
}
m_rfFrames = 0U;
m_rfErrs = 0U;
m_rfBits = 1U;
m_rfFrames = 0U;
m_rfErrs = ber;
m_rfBits = 368U;
m_rfTimeoutTimer.start();
m_minRSSI = m_rssi;
m_maxRSSI = m_rssi;
m_aveRSSI = m_rssi;
m_minRSSI = m_rssi;
m_maxRSSI = m_rssi;
m_aveRSSI = m_rssi;
m_rssiCount = 1U;
m_rfLSFn = 0U;
m_rfFN = 0U;
#if defined(DUMP_M17)
openFile();
@@ -233,14 +235,15 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
return false;
}
m_rfFrames = 0U;
m_rfErrs = 0U;
m_rfBits = 1U;
m_rfFrames = 0U;
m_rfErrs = 0U;
m_rfBits = 1U;
m_rfTimeoutTimer.start();
m_minRSSI = m_rssi;
m_maxRSSI = m_rssi;
m_aveRSSI = m_rssi;
m_minRSSI = m_rssi;
m_maxRSSI = m_rssi;
m_aveRSSI = m_rssi;
m_rssiCount = 1U;
m_rfFN = 0U;
#if defined(DUMP_M17)
openFile();
@@ -257,59 +260,64 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
#endif
CM17Convolution conv;
unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES];
unsigned int convBER = conv.decodeData(data + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES, frame);
unsigned int errors = conv.decodeData(data + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES, frame);
unsigned int fn = ((frame[0U] << 8) + (frame[1U] << 0)) & 0x7FU;
// If we have a BER of less than 12, then we consider the audio to be usable
bool valid = errors < 12U;
unsigned char rfData[2U + M17_FRAME_LENGTH_BYTES];
if (!valid) {
frame[0U] = (m_rfFN >> 8) & 0xFFU;
frame[1U] = (m_rfFN >> 0) & 0xFFU;
rfData[0U] = TAG_DATA1;
rfData[1U] = 0x00U;
// Generate the sync
CSync::addM17StreamSync(rfData + 2U);
unsigned char lich[M17_LICH_FRAGMENT_LENGTH_BYTES];
m_rfLSF.getFragment(lich, m_rfLSFn);
// Add the fragment number
lich[5U] = (m_rfLSFn & 0x07U) << 5;
unsigned int frag1, frag2, frag3, frag4;
CM17Utils::splitFragmentLICH(lich, frag1, frag2, frag3, frag4);
// Add Golay to the LICH fragment here
unsigned int lich1 = CGolay24128::encode24128(frag1);
unsigned int lich2 = CGolay24128::encode24128(frag2);
unsigned int lich3 = CGolay24128::encode24128(frag3);
unsigned int lich4 = CGolay24128::encode24128(frag4);
CM17Utils::combineFragmentLICHFEC(lich1, lich2, lich3, lich4, rfData + 2U + M17_SYNC_LENGTH_BYTES);
// Add the Convolution FEC
conv.encodeData(frame, rfData + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES);
// Calculate the BER
unsigned int errors = 0U;
for (unsigned int i = 0U; i < (M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES); i++) {
unsigned int offset = i + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES;
errors += CUtils::countBits(rfData[offset] ^ data[offset]);
::memcpy(frame + 2U + 0U, M17_3200_SILENCE, 8U);
::memcpy(frame + 2U + 8U, M17_3200_SILENCE, 8U);
} else {
m_rfFN = ((frame[0U] << 8) + (frame[1U] << 0)) & 0x7FU;
}
LogDebug("M17, FN: %u, errs: %u/%u/144 (%.1f%%)", fn & 0x7FU, errors, convBER, float(errors) / 1.44F);
LogDebug("M17, FN: %u, errs: %u/272 (%.1f%%)", m_rfFN & 0x7FU, errors, float(errors) / 2.72F);
m_rfBits += M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS;
m_rfBits += 272U;
m_rfErrs += errors;
float ber = float(m_rfErrs) / float(m_rfBits);
m_display->writeM17BER(ber);
unsigned char temp[M17_FRAME_LENGTH_BYTES];
interleaver(rfData + 2U, temp);
decorrelator(temp, rfData + 2U);
if (m_duplex) {
unsigned char rfData[2U + M17_FRAME_LENGTH_BYTES];
rfData[0U] = TAG_DATA1;
rfData[1U] = 0x00U;
// Generate the sync
CSync::addM17StreamSync(rfData + 2U);
unsigned char lich[M17_LICH_FRAGMENT_LENGTH_BYTES];
m_rfLSF.getFragment(lich, m_rfLSFn);
// Add the fragment number
lich[5U] = (m_rfLSFn & 0x07U) << 5;
unsigned int frag1, frag2, frag3, frag4;
CM17Utils::splitFragmentLICH(lich, frag1, frag2, frag3, frag4);
// Add Golay to the LICH fragment here
unsigned int lich1 = CGolay24128::encode24128(frag1);
unsigned int lich2 = CGolay24128::encode24128(frag2);
unsigned int lich3 = CGolay24128::encode24128(frag3);
unsigned int lich4 = CGolay24128::encode24128(frag4);
CM17Utils::combineFragmentLICHFEC(lich1, lich2, lich3, lich4, rfData + 2U + M17_SYNC_LENGTH_BYTES);
// Add the Convolution FEC
conv.encodeData(frame, rfData + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES);
unsigned char temp[M17_FRAME_LENGTH_BYTES];
interleaver(rfData + 2U, temp);
decorrelator(temp, rfData + 2U);
if (m_duplex)
writeQueueRF(rfData);
}
if (m_network != NULL && m_rfTimeoutTimer.isRunning() && !m_rfTimeoutTimer.hasExpired()) {
unsigned char netData[M17_LSF_LENGTH_BYTES + M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES];
@@ -325,13 +333,14 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
}
m_rfFrames++;
m_rfFN++;
m_rfLSFn++;
if (m_rfLSFn >= 6U)
m_rfLSFn = 0U;
// Only check for the EOT marker if the frame has a valid CRC
if ((fn & 0x8000U) == 0x8000U) {
// Only check for the EOT marker if the frame has a reasonable BER
if (valid && (m_rfFN & 0x8000U) == 0x8000U) {
std::string source = m_rfLSF.getSource();
std::string dest = m_rfLSF.getDest();