/* * Copyright (C) 2009-2018,2020,2024 by Jonathan Naylor G4KLX * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "Config.h" #if defined(MODE_DPMR) #include "Globals.h" #include "DPMRRX.h" #include "Utils.h" const q15_t SCALING_FACTOR = 18750; // Q15(0.55) const uint8_t MAX_FS_BIT_START_ERRS = 1U; const uint8_t MAX_FS_BIT_RUN_ERRS = 3U; const uint8_t MAX_FS_SYMBOLS_ERRS = 2U; const uint8_t BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U}; #define WRITE_BIT1(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i)&7]) const uint8_t NOAVEPTR = 99U; const uint16_t NOENDPTR = 9999U; const unsigned int MAX_FS_FRAMES = 5U + 1U; CDPMRRX::CDPMRRX() : m_state(DPMRRXS_NONE), m_bitBuffer(), m_buffer(), m_bitPtr(0U), m_dataPtr(0U), m_startPtr(NOENDPTR), m_endPtr(NOENDPTR), m_fsPtr(NOENDPTR), m_minFSPtr(NOENDPTR), m_maxFSPtr(NOENDPTR), m_maxCorr(0), m_lostCount(0U), m_countdown(0U), m_centre(), m_centreVal(0), m_threshold(), m_thresholdVal(0), m_averagePtr(NOAVEPTR), m_rssiAccum(0U), m_rssiCount(0U) { } void CDPMRRX::reset() { m_state = DPMRRXS_NONE; m_dataPtr = 0U; m_bitPtr = 0U; m_maxCorr = 0; m_averagePtr = NOAVEPTR; m_startPtr = NOENDPTR; m_endPtr = NOENDPTR; m_fsPtr = NOENDPTR; m_minFSPtr = NOENDPTR; m_maxFSPtr = NOENDPTR; m_centreVal = 0; m_thresholdVal = 0; m_lostCount = 0U; m_countdown = 0U; m_rssiAccum = 0U; m_rssiCount = 0U; } void CDPMRRX::samples(const q15_t* samples, uint16_t* rssi, uint8_t length) { for (uint8_t i = 0U; i < length; i++) { q15_t sample = samples[i]; m_rssiAccum += rssi[i]; m_rssiCount++; m_bitBuffer[m_bitPtr] <<= 1; if (sample < 0) m_bitBuffer[m_bitPtr] |= 0x01U; m_buffer[m_dataPtr] = sample; switch (m_state) { case DPMRRXS_HEADER: processHeader(sample); break; case DPMRRXS_DATA: processData(sample); break; case DPMRRXS_EOT: processEOT(sample); break; default: processNone(sample); break; } m_dataPtr++; if (m_dataPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_dataPtr = 0U; m_bitPtr++; if (m_bitPtr >= DPMR_RADIO_SYMBOL_LENGTH) m_bitPtr = 0U; } } void CDPMRRX::processNone(q15_t sample) { // Process the FS1/Header sync bool ret = correlateFS1(); if (ret) { // On the first sync, start the countdown to the state change if (m_countdown == 0U) { m_rssiAccum = 0U; m_rssiCount = 0U; io.setDecode(true); io.setADCDetection(true); m_averagePtr = NOAVEPTR; m_countdown = 5U; } } if (m_countdown > 0U) m_countdown--; if (m_countdown == 1U) { m_minFSPtr = m_fsPtr + DPMR_HEADER_FRAME_LENGTH_SAMPLES - 1U; if (m_minFSPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_minFSPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; m_maxFSPtr = m_fsPtr + 1U; if (m_maxFSPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_maxFSPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; m_state = DPMRRXS_HEADER; m_countdown = 0U; } // Process the FS2/Data sync ret = correlateFS2(); if (ret) { // On the first sync, start the countdown to the state change if (m_countdown == 0U) { m_rssiAccum = 0U; m_rssiCount = 0U; io.setDecode(true); io.setADCDetection(true); m_averagePtr = NOAVEPTR; m_countdown = 5U; } } if (m_countdown > 0U) m_countdown--; if (m_countdown == 1U) { m_minFSPtr = m_fsPtr + DPMR_DATA_FRAME_LENGTH_SAMPLES - 1U; if (m_minFSPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_minFSPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; m_maxFSPtr = m_fsPtr + 1U; if (m_maxFSPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_maxFSPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; m_state = DPMRRXS_DATA; m_countdown = 0U; } // Don't process FS3/End sync here } void CDPMRRX::processHeader(q15_t sample) { if (m_dataPtr == m_endPtr) { m_minFSPtr = m_fsPtr + DPMR_HEADER_FRAME_LENGTH_SAMPLES - 1U; if (m_minFSPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_minFSPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; m_maxFSPtr = m_fsPtr + 1U; if (m_maxFSPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_maxFSPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; calculateLevels(m_startPtr, DPMR_HEADER_FRAME_LENGTH_SYMBOLS); DEBUG4("DPMRRX: FS1 sync found pos/centre/threshold", m_fsPtr, m_centreVal, m_thresholdVal); uint8_t frame[DPMR_HEADER_FRAME_LENGTH_BYTES + 3U]; samplesToBits(m_startPtr, DPMR_HEADER_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal); frame[0U] = 0x01U; writeRSSIHeader(frame); m_state = DPMRRXS_DATA; m_maxCorr = 0; } } void CDPMRRX::processData(q15_t sample) { if (m_minFSPtr < m_maxFSPtr) { if (m_dataPtr >= m_minFSPtr && m_dataPtr <= m_maxFSPtr) { correlateFS2(); bool ret = correlateFS3(); if (ret) m_state = DPMRRXS_EOT; } } else { if (m_dataPtr >= m_minFSPtr || m_dataPtr <= m_maxFSPtr) { correlateFS2(); bool ret = correlateFS3(); if (ret) m_state = DPMRRXS_EOT; } } if (m_dataPtr == m_endPtr) { // Only update the centre and threshold if they are from a good sync if (m_lostCount == MAX_FS2_FRAMES) { m_minFSPtr = m_fsPtr + DPMR_DATA_FRAME_LENGTH_SAMPLES - 1U; if (m_minFSPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_minFSPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; m_maxFSPtr = m_fsPtr + 1U; if (m_maxFSPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_maxFSPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; } calculateLevels(m_startPtr, DPMR_DATA_FRAME_LENGTH_SYMBOLS); DEBUG4("DPMRRX: FS2 sync found pos/centre/threshold", m_fsPtr, m_centreVal, m_thresholdVal); uint8_t frame[DPMR_DATA_FRAME_LENGTH_BYTES + 3U]; samplesToBits(m_startPtr, DPMR_DATA_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal); // We've not seen a data sync for too long, signal RXLOST and change to RX_NONE m_lostCount--; if (m_lostCount == 0U) { DEBUG1("DPMRRX: FS2 sync timed out, lost lock"); io.setDecode(false); io.setADCDetection(false); serial.writeDPMRLost(); m_state = DPMRRXS_NONE; m_endPtr = NOENDPTR; m_averagePtr = NOAVEPTR; m_countdown = 0U; m_maxCorr = 0; } else { frame[0U] = m_lostCount == (MAX_FS2_FRAMES - 1U) ? 0x01U : 0x00U; writeRSSIData(frame); m_maxCorr = 0; } } } void CDPMRRX::processEnd(q15_t sample) { if (m_dataPtr == m_endPtr) { calculateLevels(m_startPtr, DPMR_END_FRAME_LENGTH_SYMBOLS); DEBUG4("DPMRRX: FS3 sync found pos/centre/threshold", m_fsPtr, m_centreVal, m_thresholdVal); uint8_t frame[DPMR_END_FRAME_LENGTH_BYTES + 3U]; samplesToBits(m_startPtr, DPMR_END_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal); frame[0U] = 0x01U; io.setDecode(false); io.setADCDetection(false); writeRSSIEnd(frame); m_state = DPMRRXS_NONE; m_endPtr = NOENDPTR; m_averagePtr = NOAVEPTR; m_countdown = 0U; m_maxCorr = 0; } } bool CDPMRRX::correlateFS1() { if (countBits32(m_bitBuffer[m_bitPtr] ^ DPMR_FS1_SYMBOLS) <= MAX_FS1_SYMBOLS_ERRS) { uint16_t ptr = m_dataPtr + DPMR_HEADER_FRAME_LENGTH_SAMPLES - DPMR_FS1_LENGTH_SAMPLES + DPMR_RADIO_SYMBOL_LENGTH; if (ptr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) ptr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; q31_t corr = 0; q15_t min = 16000; q15_t max = -16000; for (uint8_t i = 0U; i < DPMR_FS1_LENGTH_SYMBOLS; i++) { q15_t val = m_buffer[ptr]; if (val > max) max = val; if (val < min) min = val; switch (DPMR_FS1_SYMBOLS_VALUES[i]) { case +3: corr -= (val + val + val); break; case +1: corr -= val; break; case -1: corr += val; break; default: // -3 corr += (val + val + val); break; } ptr += DPMR_RADIO_SYMBOL_LENGTH; if (ptr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) ptr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; } if (corr > m_maxCorr) { if (m_averagePtr == NOAVEPTR) { m_centreVal = (max + min) >> 1; q31_t v1 = (max - m_centreVal) * SCALING_FACTOR; m_thresholdVal = q15_t(v1 >> 15); } uint16_t startPtr = m_dataPtr + DPMR_HEADER_FRAME_LENGTH_SAMPLES - DPMR_FS1_LENGTH_SAMPLES + DPMR_RADIO_SYMBOL_LENGTH; if (startPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) startPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; uint8_t sync[DPMR_FS1_BYTES_LENGTH]; samplesToBits(startPtr, DPMR_FS1_LENGTH_SYMBOLS, sync, 0U, m_centreVal, m_thresholdVal); uint8_t errs = 0U; for (uint8_t i = 0U; i < DPMR_FS1_BYTES_LENGTH; i++) errs += countBits8(sync[i] ^ DPMR_FS1_BYTES[i]); if (errs <= MAX_FS1_BIT_START_ERRS) { m_maxCorr = corr; m_lostCount = MAX_FS1_FRAMES; m_fsPtr = m_dataPtr; m_startPtr = startPtr; m_endPtr = m_dataPtr + DPMR_HEADER_FRAME_LENGTH_SAMPLES - DPMR_FS1_LENGTH_SAMPLES - 1U; if (m_endPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_endPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; return true; } } } return false; } bool CDPMRRX::correlateFS2() { if (countBits32(m_bitBuffer[m_bitPtr] ^ DPMR_FS2_SYMBOLS) <= MAX_FS2_SYMBOLS_ERRS) { uint16_t ptr = m_dataPtr + DPMR_DATA_FRAME_LENGTH_SAMPLES - DPMR_FS2_LENGTH_SAMPLES + DPMR_RADIO_SYMBOL_LENGTH; if (ptr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) ptr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; q31_t corr = 0; q15_t min = 16000; q15_t max = -16000; for (uint8_t i = 0U; i < DPMR_FS2_LENGTH_SYMBOLS; i++) { q15_t val = m_buffer[ptr]; if (val > max) max = val; if (val < min) min = val; switch (DPMR_FS2_SYMBOLS_VALUES[i]) { case +3: corr -= (val + val + val); break; case +1: corr -= val; break; case -1: corr += val; break; default: // -3 corr += (val + val + val); break; } ptr += DPMR_RADIO_SYMBOL_LENGTH; if (ptr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) ptr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; } if (corr > m_maxCorr) { if (m_averagePtr == NOAVEPTR) { m_centreVal = (max + min) >> 1; q31_t v1 = (max - m_centreVal) * SCALING_FACTOR; m_thresholdVal = q15_t(v1 >> 15); } uint16_t startPtr = m_dataPtr + DPMR_DATA_FRAME_LENGTH_SAMPLES - DPMR_FS2_LENGTH_SAMPLES + DPMR_RADIO_SYMBOL_LENGTH; if (startPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) startPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; uint8_t sync[DPMR_FS2_BYTES_LENGTH]; samplesToBits(startPtr, DPMR_FS2_LENGTH_SYMBOLS, sync, 0U, m_centreVal, m_thresholdVal); uint8_t maxErrs; if (m_state == DPMRRXS_NONE) maxErrs = MAX_FS2_BIT_START_ERRS; else maxErrs = MAX_FS2_BIT_RUN_ERRS; uint8_t errs = 0U; for (uint8_t i = 0U; i < DPMR_FS2_BYTES_LENGTH; i++) errs += countBits8(sync[i] ^ DPMR_FS2_BYTES[i]); if (errs <= maxErrs) { m_maxCorr = corr; m_lostCount = MAX_FS2_FRAMES; m_fsPtr = m_dataPtr; m_startPtr = startPtr; m_endPtr = m_dataPtr + DPMR_DATA_FRAME_LENGTH_SAMPLES - DPMR_FS2_LENGTH_SAMPLES - 1U; if (m_endPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_endPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; return true; } } } return false; } bool CDPMRRX::correlateFS3() { if (countBits32(m_bitBuffer[m_bitPtr] ^ DPMR_FS3_SYMBOLS) <= MAX_FS3_SYMBOLS_ERRS) { uint16_t ptr = m_dataPtr + DPMR_END_FRAME_LENGTH_SAMPLES - DPMR_FS3_LENGTH_SAMPLES + DPMR_RADIO_SYMBOL_LENGTH; if (ptr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) ptr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; q31_t corr = 0; q15_t min = 16000; q15_t max = -16000; for (uint8_t i = 0U; i < DPMR_FS3_LENGTH_SYMBOLS; i++) { q15_t val = m_buffer[ptr]; if (val > max) max = val; if (val < min) min = val; switch (DPMR_FS3_SYMBOLS_VALUES[i]) { case +3: corr -= (val + val + val); break; case +1: corr -= val; break; case -1: corr += val; break; default: // -3 corr += (val + val + val); break; } ptr += DPMR_RADIO_SYMBOL_LENGTH; if (ptr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) ptr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; } if (corr > m_maxCorr) { if (m_averagePtr == NOAVEPTR) { m_centreVal = (max + min) >> 1; q31_t v1 = (max - m_centreVal) * SCALING_FACTOR; m_thresholdVal = q15_t(v1 >> 15); } uint16_t startPtr = m_dataPtr + DPMR_END_FRAME_LENGTH_SAMPLES - DPMR_FS3_LENGTH_SAMPLES + DPMR_RADIO_SYMBOL_LENGTH; if (startPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) startPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; uint8_t sync[DPMR_FS1_BYTES_LENGTH]; samplesToBits(startPtr, DPMR_FS3_LENGTH_SYMBOLS, sync, 0U, m_centreVal, m_thresholdVal); uint8_t errs = 0U; for (uint8_t i = 0U; i < DPMR_FS3_BYTES_LENGTH; i++) errs += countBits8(sync[i] ^ DPMR_FS3_BYTES[i]); if (errs <= MAX_FS3_BIT_RUN_ERRS) { m_maxCorr = corr; m_lostCount = MAX_FS3_FRAMES; m_fsPtr = m_dataPtr; m_startPtr = startPtr; m_endPtr = m_dataPtr + DPMR_END_FRAME_LENGTH_SAMPLES - DPMR_FS3_LENGTH_SAMPLES - 1U; if (m_endPtr >= DPMR_DATA_FRAME_LENGTH_SAMPLES) m_endPtr -= DPMR_DATA_FRAME_LENGTH_SAMPLES; return true; } } } return false; } void CDPMRRX::calculateLevels(uint16_t start, uint16_t count) { q15_t maxPos = -16000; q15_t minPos = 16000; q15_t maxNeg = 16000; q15_t minNeg = -16000; for (uint16_t i = 0U; i < count; i++) { q15_t sample = m_buffer[start]; if (sample > 0) { if (sample > maxPos) maxPos = sample; if (sample < minPos) minPos = sample; } else { if (sample < maxNeg) maxNeg = sample; if (sample > minNeg) minNeg = sample; } start += DPMR_RADIO_SYMBOL_LENGTH; if (start >= DPMR_FRAME_LENGTH_SAMPLES) start -= DPMR_FRAME_LENGTH_SAMPLES; } q15_t posThresh = (maxPos + minPos) >> 1; q15_t negThresh = (maxNeg + minNeg) >> 1; q15_t centre = (posThresh + negThresh) >> 1; q15_t threshold = posThresh - centre; DEBUG5("DPMRRX: pos/neg/centre/threshold", posThresh, negThresh, centre, threshold); if (m_averagePtr == NOAVEPTR) { for (uint8_t i = 0U; i < 16U; i++) { m_centre[i] = centre; m_threshold[i] = threshold; } m_averagePtr = 0U; } else { m_centre[m_averagePtr] = centre; m_threshold[m_averagePtr] = threshold; m_averagePtr++; if (m_averagePtr >= 16U) m_averagePtr = 0U; } m_centreVal = 0; m_thresholdVal = 0; for (uint8_t i = 0U; i < 16U; i++) { m_centreVal += m_centre[i]; m_thresholdVal += m_threshold[i]; } m_centreVal >>= 4; m_thresholdVal >>= 4; } void CDPMRRX::samplesToBits(uint16_t start, uint16_t count, uint8_t* buffer, uint16_t offset, q15_t centre, q15_t threshold) { for (uint16_t i = 0U; i < count; i++) { q15_t sample = m_buffer[start] - centre; if (sample < -threshold) { WRITE_BIT1(buffer, offset, false); offset++; WRITE_BIT1(buffer, offset, true); offset++; } else if (sample < 0) { WRITE_BIT1(buffer, offset, false); offset++; WRITE_BIT1(buffer, offset, false); offset++; } else if (sample < threshold) { WRITE_BIT1(buffer, offset, true); offset++; WRITE_BIT1(buffer, offset, false); offset++; } else { WRITE_BIT1(buffer, offset, true); offset++; WRITE_BIT1(buffer, offset, true); offset++; } start += DPMR_RADIO_SYMBOL_LENGTH; if (start >= DPMR_FRAME_LENGTH_SAMPLES) start -= DPMR_FRAME_LENGTH_SAMPLES; } } void CDPMRRX::writeRSSIHeader(uint8_t* data) { #if defined(SEND_RSSI_DATA) if (m_rssiCount > 0U) { uint16_t rssi = m_rssiAccum / m_rssiCount; data[49U] = (rssi >> 8) & 0xFFU; data[50U] = (rssi >> 0) & 0xFFU; serial.writeDPMRHeader(data, DPMR_HEADER_FRAME_LENGTH_BYTES + 3U); } else { serial.writeDPMRHeader(data, DPMR_HEADER_FRAME_LENGTH_BYTES + 1U); } #else serial.writeDPMRHeader(data, DPMR_HEADER_FRAME_LENGTH_BYTES + 1U); #endif m_rssiAccum = 0U; m_rssiCount = 0U; } void CDPMRRX::writeRSSIData(uint8_t* data) { #if defined(SEND_RSSI_DATA) if (m_rssiCount > 0U) { uint16_t rssi = m_rssiAccum / m_rssiCount; data[49U] = (rssi >> 8) & 0xFFU; data[50U] = (rssi >> 0) & 0xFFU; serial.writeDPMRData(data, DPMR_DATA_FRAME_LENGTH_BYTES + 3U); } else { serial.writeDPMRData(data, DPMR_DATA_FRAME_LENGTH_BYTES + 1U); } #else serial.writeDPMRData(data, DPMR_DATA_FRAME_LENGTH_BYTES + 1U); #endif m_rssiAccum = 0U; m_rssiCount = 0U; } #endif