* added Radio::loop() virtual function

* RadioLibWrapper:  new isChannelActive() based on current RSSI being above noise_floor + THRESHOLD

src/Dispatcher.cpp

@@ -36,6 +36,8 @@ uint32_t Dispatcher::getCADFailMaxDuration() const {
 }
 
 void Dispatcher::loop() {
+  _radio->loop();
+
   // check for radio 'stuck' in mode other than Rx
   bool is_recv = _radio->isInRecvMode();
   if (is_recv != prev_isrecv_mode) {

src/Dispatcher.h

@@ -56,6 +56,11 @@ public:
   */
   virtual void onSendFinished() = 0;
 
+  /**
+   * \brief  do any processing needed on each loop cycle
+   */
+  virtual void loop() { }
+
   virtual bool isInRecvMode() const = 0;
 
   /**

src/helpers/CustomLLCC68Wrapper.h

@@ -9,6 +9,9 @@ public:
   bool isReceivingPacket() override { 
     return ((CustomLLCC68 *)_radio)->isReceiving();
   }
+  float getCurrentRSSI() override {
+    return ((CustomLLCC68 *)_radio)->getRSSI(false);
+  }
   float getLastRSSI() const override { return ((CustomLLCC68 *)_radio)->getRSSI(); }
   float getLastSNR() const override { return ((CustomLLCC68 *)_radio)->getSNR(); }
 

src/helpers/CustomLR1110Wrapper.h

@@ -9,6 +9,11 @@ public:
   bool isReceivingPacket() override { 
     return ((CustomLR1110 *)_radio)->isReceiving();
   }
+  float getCurrentRSSI() override {
+    float rssi = -110;
+    ((CustomLR1110 *)_radio)->getRssiInst(&rssi);
+    return rssi;
+  }
 
   void onSendFinished() override {
     RadioLibWrapper::onSendFinished();

src/helpers/CustomSTM32WLxWrapper.h

@@ -10,6 +10,9 @@ public:
   bool isReceivingPacket() override { 
     return ((CustomSTM32WLx *)_radio)->isReceiving();
   }
+  float getCurrentRSSI() override {
+    return ((CustomSTM32WLx *)_radio)->getRSSI(false);
+  }
   float getLastRSSI() const override { return ((CustomSTM32WLx *)_radio)->getRSSI(); }
   float getLastSNR() const override { return ((CustomSTM32WLx *)_radio)->getSNR(); }
 

src/helpers/CustomSX1262Wrapper.h

@@ -9,6 +9,9 @@ public:
   bool isReceivingPacket() override { 
     return ((CustomSX1262 *)_radio)->isReceiving();
   }
+  float getCurrentRSSI() override {
+    return ((CustomSX1262 *)_radio)->getRSSI(false);
+  }
   float getLastRSSI() const override { return ((CustomSX1262 *)_radio)->getRSSI(); }
   float getLastSNR() const override { return ((CustomSX1262 *)_radio)->getSNR(); }
 

src/helpers/CustomSX1268Wrapper.h

@@ -9,6 +9,9 @@ public:
   bool isReceivingPacket() override { 
     return ((CustomSX1268 *)_radio)->isReceiving();
   }
+  float getCurrentRSSI() override {
+    return ((CustomSX1268 *)_radio)->getRSSI(false);
+  }
   float getLastRSSI() const override { return ((CustomSX1268 *)_radio)->getRSSI(); }
   float getLastSNR() const override { return ((CustomSX1268 *)_radio)->getSNR(); }
 

src/helpers/CustomSX1276Wrapper.h

@@ -9,6 +9,9 @@ public:
   bool isReceivingPacket() override { 
     return ((CustomSX1276 *)_radio)->isReceiving();
   }
+  float getCurrentRSSI() override {
+    return ((CustomSX1276 *)_radio)->getRSSI(false);
+  }
   float getLastRSSI() const override { return ((CustomSX1276 *)_radio)->getRSSI(); }
   float getLastSNR() const override { return ((CustomSX1276 *)_radio)->getSNR(); }
 

src/helpers/RadioLibWrappers.cpp

@@ -8,6 +8,12 @@
 #define STATE_TX_DONE    4
 #define STATE_INT_READY 16
 
+#ifndef INTERFERENCE_THRESHOLD_DB
+  #define INTERFERENCE_THRESHOLD_DB   14
+#endif
+
+#define NUM_NOISE_FLOOR_SAMPLES  64
+
 static volatile uint8_t state = STATE_IDLE;
 
 // this function is called when a complete packet
@@ -28,6 +34,12 @@ void RadioLibWrapper::begin() {
   if (_board->getStartupReason() == BD_STARTUP_RX_PACKET) {  // received a LoRa packet (while in deep sleep)
     setFlag(); // LoRa packet is already received
   }
+
+  _noise_floor = -140;
+
+  // start average out some samples
+  _num_floor_samples = 0;
+  _floor_sample_sum = 0;
 }
 
 void RadioLibWrapper::idle() {
@@ -35,6 +47,20 @@ void RadioLibWrapper::idle() {
   state = STATE_IDLE;   // need another startReceive()
 }
 
+void RadioLibWrapper::loop() {
+  if (state == STATE_RX && _num_floor_samples < NUM_NOISE_FLOOR_SAMPLES) {
+    if (!isReceivingPacket()) {
+      _num_floor_samples++;
+      _floor_sample_sum += getCurrentRSSI();
+    }
+  } else if (_floor_sample_sum != 0) {
+    _noise_floor = _floor_sample_sum / NUM_NOISE_FLOOR_SAMPLES;
+    _floor_sample_sum = 0;
+
+    MESH_DEBUG_PRINTLN("RadioLibWrapper: noise_floor = %d", (int)_noise_floor);
+  }
+}
+
 void RadioLibWrapper::startRecv() {
   int err = _radio->startReceive();
   if (err == RADIOLIB_ERR_NONE) {
@@ -109,15 +135,7 @@ void RadioLibWrapper::onSendFinished() {
 }
 
 bool RadioLibWrapper::isChannelActive() {
-  idle();  // put sx126x into standby
-  // do some basic CAD (blocks for ~12780 micros (on SF 10)!)
-  bool activity = _radio->scanChannel() == RADIOLIB_LORA_DETECTED;
-  if (activity) {
-    startRecv();
-  } else {
-    idle();
-  }
-  return activity;
+  return getCurrentRSSI() > _noise_floor + INTERFERENCE_THRESHOLD_DB;
 }
 
 float RadioLibWrapper::getLastRSSI() const {

src/helpers/RadioLibWrappers.h

@@ -8,11 +8,15 @@ protected:
   PhysicalLayer* _radio;
   mesh::MainBoard* _board;
   uint32_t n_recv, n_sent;
+  int16_t _noise_floor;
+  uint16_t _num_floor_samples;
+  int32_t _floor_sample_sum;
 
   void idle();
   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; }
@@ -32,6 +36,8 @@ public:
     return isChannelActive();
   }
 
+  void loop() override;
+
   uint32_t getPacketsRecv() const { return n_recv; }
   uint32_t getPacketsSent() const { return n_sent; }
   void resetStats() { n_recv = n_sent = 0; }