Dynamic CAD sensitivity

Probe every 4 seconds to measure actual channel activity. If channel
seems busy we adjust CAD to be less sensitive. If channel seems empty
maximum CAD sensitivity.

Author: weebl2000

examples/simple_repeater/MyMesh.h

@@ -216,6 +216,7 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
   void removeNeighbor(const uint8_t* pubkey, int key_len) override;
   void formatStatsReply(char *reply) override;
   void formatRadioStatsReply(char *reply) override;
+  mesh::Radio* getRadio() override { return _radio; }
   void formatPacketStatsReply(char *reply) override;
   void startRegionsLoad() override;
   bool saveRegions() override;

examples/simple_room_server/MyMesh.h

@@ -212,6 +212,7 @@ class MyMesh : public mesh::Mesh, public CommonCLICallbacks {
   }
   void formatStatsReply(char *reply) override;
   void formatRadioStatsReply(char *reply) override;
+  mesh::Radio* getRadio() override { return _radio; }
   void formatPacketStatsReply(char *reply) override;
   void startRegionsLoad() override;
   bool saveRegions() override;

examples/simple_sensor/SensorMesh.h

@@ -73,6 +73,7 @@ class SensorMesh : public mesh::Mesh, public CommonCLICallbacks {
   }
   void formatStatsReply(char *reply) override;
   void formatRadioStatsReply(char *reply) override;
+  mesh::Radio* getRadio() override { return _radio; }
   void formatPacketStatsReply(char *reply) override;
   mesh::LocalIdentity& getSelfId() override { return self_id; }
   void saveIdentity(const mesh::LocalIdentity& new_id) override;

src/Dispatcher.h

@@ -67,6 +67,14 @@ class Radio {
 
   virtual void setCADEnabled(bool enable) { }
 
+  /**
+   * \brief  query CAD auto-calibration state.
+   * \param  peak_offset  current detPeak offset above the radio's default
+   * \param  hits/count   ambient CAD detections in the last evaluated probe window
+   * \returns false if this radio doesn't support CAD detPeak tuning.
+  */
+  virtual bool getCADCalibState(uint8_t& peak_offset, uint8_t& hits, uint8_t& count) const { return false; }
+
   virtual void resetAGC() { }
 
   virtual bool isInRecvMode() const = 0;

src/Mesh.cpp

@@ -27,7 +27,7 @@ uint8_t Mesh::getExtraAckTransmitCount() const {
 }
 
 uint32_t Mesh::getCADFailRetryDelay() const {
-  return _rng->nextInt(1, 4)*120;
+  return 120 + _rng->nextInt(0, 241);   // continuous 120..360ms, so nearby nodes don't retry in lock-step
 }
 
 int Mesh::searchPeersByHash(const uint8_t* hash) {

src/helpers/CommonCLI.cpp

@@ -811,7 +811,13 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
   } else if (memcmp(config, "int.thresh", 10) == 0) {
     sprintf(reply, "> %d", (uint32_t) _prefs->interference_threshold);
   } else if (memcmp(config, "cad", 3) == 0) {
-    sprintf(reply, "> %s", _prefs->cad_enabled ? "on" : "off");
+    uint8_t peak_offset, hits, count;
+    mesh::Radio* radio = _callbacks->getRadio();
+    if (_prefs->cad_enabled && radio != NULL && radio->getCADCalibState(peak_offset, hits, count)) {
+      sprintf(reply, "> on (detPeak +%d, ambient %d/%d)", (int)peak_offset, (int)hits, (int)count);
+    } else {
+      sprintf(reply, "> %s", _prefs->cad_enabled ? "on" : "off");
+    }
   } else if (memcmp(config, "agc.reset.interval", 18) == 0) {
     sprintf(reply, "> %d", ((uint32_t) _prefs->agc_reset_interval) * 4);
   } else if (memcmp(config, "multi.acks", 10) == 0) {

src/helpers/CommonCLI.h

@@ -81,6 +81,7 @@ class CommonCLICallbacks {
   virtual void eraseLogFile() = 0;
   virtual void dumpLogFile() = 0;
   virtual void setTxPower(int8_t power_dbm) = 0;
+  virtual mesh::Radio* getRadio() { return NULL; }
   virtual void formatNeighborsReply(char *reply) = 0;
   virtual void removeNeighbor(const uint8_t* pubkey, int key_len) {
     // no op by default

src/helpers/radiolib/CustomLLCC68Wrapper.h

@@ -30,6 +30,7 @@ class CustomLLCC68Wrapper : public RadioLibWrapper {
     return packetScoreInt(snr, sf, packet_len);
   }
   uint8_t getSpreadingFactor() const override { return ((CustomLLCC68 *)_radio)->spreadingFactor; }
+  uint8_t getCADDetPeakBase() const override { return getSpreadingFactor() + 13; }  // Semtech DS.SX1261-2 recommended detPeak
 
   void doResetAGC() override { sx126xResetAGC((SX126x *)_radio); }
 

src/helpers/radiolib/CustomLR1110Wrapper.h

@@ -40,6 +40,12 @@ class CustomLR1110Wrapper : public RadioLibWrapper {
   float getLastSNR() const override { return ((CustomLR1110 *)_radio)->getSNR(); }
 
   uint8_t getSpreadingFactor() const override { return ((CustomLR1110 *)_radio)->getSpreadingFactor(); }
+  uint8_t getCADDetPeakBase() const override {
+    // RadioLib LR11x0 default detPeak per SF5..12 (different scale than SX126x)
+    static const uint8_t detPeakValues[8] = { 48, 48, 50, 55, 55, 59, 61, 65 };
+    uint8_t sf = getSpreadingFactor();
+    return (sf >= 5 && sf <= 12) ? detPeakValues[sf - 5] : 0;
+  }
 
   bool setRxBoostedGainMode(bool en) override {
     return ((CustomLR1110 *)_radio)->setRxBoostedGainMode(en) == RADIOLIB_ERR_NONE;

src/helpers/radiolib/CustomSTM32WLxWrapper.h

@@ -31,6 +31,7 @@ class CustomSTM32WLxWrapper : public RadioLibWrapper {
     return packetScoreInt(snr, sf, packet_len);
   }
   uint8_t getSpreadingFactor() const override { return ((CustomSTM32WLx *)_radio)->spreadingFactor; }
+  uint8_t getCADDetPeakBase() const override { return getSpreadingFactor() + 13; }  // Semtech DS.SX1261-2 recommended detPeak
 
   void doResetAGC() override { sx126xResetAGC((SX126x *)_radio); }
 };