* dynamic noise floor sampling

src/Dispatcher.cpp

@@ -10,6 +10,10 @@ namespace mesh {
 
 #define MAX_RX_DELAY_MILLIS   32000  // 32 seconds
 
+#ifndef NOISE_FLOOR_CALIB_INTERVAL
+  #define NOISE_FLOOR_CALIB_INTERVAL   2000     // 2 seconds
+#endif
+
 void Dispatcher::begin() {
   n_sent_flood = n_sent_direct = 0;
   n_recv_flood = n_recv_direct = 0;
@@ -36,6 +40,10 @@ uint32_t Dispatcher::getCADFailMaxDuration() const {
 }
 
 void Dispatcher::loop() {
+  if (millisHasNowPassed(next_floor_calib_time)) {
+    _radio->triggerNoiseFloorCalibrate();
+    next_floor_calib_time = futureMillis(NOISE_FLOOR_CALIB_INTERVAL);
+  }
   _radio->loop();
 
   // check for radio 'stuck' in mode other than Rx

src/Dispatcher.h

@@ -61,6 +61,10 @@ public:
    */
   virtual void loop() { }
 
+  virtual int getNoiseFloor() const { return 0; }
+
+  virtual void triggerNoiseFloorCalibrate() { }
+
   virtual bool isInRecvMode() const = 0;
 
   /**
@@ -112,6 +116,7 @@ class Dispatcher {
   unsigned long next_tx_time;
   unsigned long cad_busy_start;
   unsigned long radio_nonrx_start;
+  unsigned long next_floor_calib_time;
   bool  prev_isrecv_mode;
   uint32_t n_sent_flood, n_sent_direct;
   uint32_t n_recv_flood, n_recv_direct;
@@ -129,6 +134,7 @@ protected:
   {
     outbound = NULL; total_air_time = 0; next_tx_time = 0;
     cad_busy_start = 0;
+    next_floor_calib_time = 0;
     _err_flags = 0;
     radio_nonrx_start = 0;
     prev_isrecv_mode = true;

src/helpers/RadioLibWrappers.cpp

@@ -35,7 +35,7 @@ void RadioLibWrapper::begin() {
     setFlag(); // LoRa packet is already received
   }
 
-  _noise_floor = -140;
+  _noise_floor = 0;
 
   // start average out some samples
   _num_floor_samples = 0;
@@ -47,13 +47,23 @@ void RadioLibWrapper::idle() {
   state = STATE_IDLE;   // need another startReceive()
 }
 
+void RadioLibWrapper::triggerNoiseFloorCalibrate() {
+  if (_num_floor_samples >= NUM_NOISE_FLOOR_SAMPLES) {  // ignore trigger if currently sampling
+    _num_floor_samples = 0;
+    _floor_sample_sum = 0;
+  }
+}
+
 void RadioLibWrapper::loop() {
   if (state == STATE_RX && _num_floor_samples < NUM_NOISE_FLOOR_SAMPLES) {
     if (!isReceivingPacket()) {
-      _num_floor_samples++;
-      _floor_sample_sum += getCurrentRSSI();
+      int rssi = getCurrentRSSI();
+      if (rssi < _noise_floor + INTERFERENCE_THRESHOLD_DB) {  // only consider samples below current floor+THRESHOLD
+        _num_floor_samples++;
+        _floor_sample_sum += rssi;
+      }
     }
-  } else if (_floor_sample_sum != 0) {
+  } else if (_num_floor_samples >= NUM_NOISE_FLOOR_SAMPLES && _floor_sample_sum != 0) {
     _noise_floor = _floor_sample_sum / NUM_NOISE_FLOOR_SAMPLES;
     _floor_sample_sum = 0;
 

src/helpers/RadioLibWrappers.h

@@ -16,7 +16,6 @@ protected:
   void startRecv();
   float packetScoreInt(float snr, int sf, int packet_len);
   virtual bool isReceivingPacket() =0;
-  virtual float getCurrentRSSI() =0;
 
 public:
   RadioLibWrapper(PhysicalLayer& radio, mesh::MainBoard& board) : _radio(&radio), _board(&board) { n_recv = n_sent = 0; }
@@ -36,6 +35,11 @@ public:
     return isChannelActive();
   }
 
+  virtual float getCurrentRSSI() =0;
+
+  int getNoiseFloor() const override { return _noise_floor; }
+  void triggerNoiseFloorCalibrate() override;
+
   void loop() override;
 
   uint32_t getPacketsRecv() const { return n_recv; }