* new Dispatcher::getCADFailRetryDelay()

examples/simple_repeater/main.cpp

@@ -20,7 +20,7 @@
 
 /* ------------------------------ Config -------------------------------- */
 
-#define FIRMWARE_VER_TEXT   "v5 (build: 25 Feb 2025)"
+#define FIRMWARE_VER_TEXT   "v6 (build: 27 Feb 2025)"
 
 #ifndef LORA_FREQ
   #define LORA_FREQ   915.0

examples/simple_room_server/main.cpp

@@ -20,7 +20,7 @@
 
 /* ------------------------------ Config -------------------------------- */
 
-#define FIRMWARE_VER_TEXT   "v5 (build: 25 Feb 2025)"
+#define FIRMWARE_VER_TEXT   "v6 (build: 27 Feb 2025)"
 
 #ifndef LORA_FREQ
   #define LORA_FREQ   915.0

src/Dispatcher.cpp

@@ -26,6 +26,10 @@ int Dispatcher::calcRxDelay(float score, uint32_t air_time) const {
   return (int) ((pow(10, 0.85f - score) - 1.0) * air_time);
 }
 
+uint32_t Dispatcher::getCADFailRetryDelay() const {
+  return 200;
+}
+
 void Dispatcher::loop() {
   if (outbound) {  // waiting for outbound send to be completed
     if (_radio->isSendComplete()) {
@@ -165,7 +169,10 @@ void Dispatcher::processRecvPacket(Packet* pkt) {
 void Dispatcher::checkSend() {
   if (_mgr->getOutboundCount() == 0) return;  // nothing waiting to send
   if (!millisHasNowPassed(next_tx_time)) return;   // still in 'radio silence' phase (from airtime budget setting)
-  if (_radio->isReceiving()) return;  // LBT - check if radio is currently mid-receive, or if channel activity
+  if (_radio->isReceiving()) {   // LBT - check if radio is currently mid-receive, or if channel activity
+    next_tx_time = futureMillis(getCADFailRetryDelay());
+    return; 
+  }
 
   outbound = _mgr->getNextOutbound(_ms->getMillis());
   if (outbound) {

src/Dispatcher.h

@@ -124,6 +124,7 @@ protected:
 
   virtual float getAirtimeBudgetFactor() const;
   virtual int calcRxDelay(float score, uint32_t air_time) const;
+  virtual uint32_t getCADFailRetryDelay() const;
 
 public:
   void begin();

src/Mesh.cpp

@@ -23,6 +23,10 @@ uint32_t Mesh::getDirectRetransmitDelay(const Packet* packet) {
   return 0;  // by default, no delay
 }
 
+uint32_t Mesh::getCADFailRetryDelay() const {
+  return _rng->nextInt(1, 4)*120;
+}
+
 int Mesh::searchPeersByHash(const uint8_t* hash) {
   return 0;  // not found
 }

src/Mesh.h

@@ -58,6 +58,8 @@ class Mesh : public Dispatcher {
 protected:
   DispatcherAction onRecvPacket(Packet* pkt) override;
 
+  virtual uint32_t getCADFailRetryDelay() const override;
+
   /**
    * \brief  Decide what to do with received packet, ie. discard, forward, or hold
    */

src/helpers/CustomLLCC68Wrapper.h

@@ -12,8 +12,11 @@ public:
     idle();  // put sx126x into standby
     // do some basic CAD (blocks for ~12780 micros (on SF 10)!)
     bool activity = (((CustomLLCC68 *)_radio)->scanChannel() == RADIOLIB_LORA_DETECTED);
-    idle();
-
+    if (activity) {
+      startRecv();
+    } else {
+      idle();
+    }
     return activity;
   }
   float getLastRSSI() const override { return ((CustomLLCC68 *)_radio)->getRSSI(); }

src/helpers/CustomLR1110Wrapper.h

@@ -12,8 +12,11 @@ public:
     idle();  // put sx126x into standby
     // do some basic CAD (blocks for ~12780 micros (on SF 10)!)
     bool activity = (((CustomLR1110 *)_radio)->scanChannel() == RADIOLIB_LORA_DETECTED);
-    idle();
-
+    if (activity) {
+      startRecv();
+    } else {
+      idle();
+    }
     return activity;
   }
 

src/helpers/CustomSX1262Wrapper.h

@@ -13,8 +13,11 @@ public:
     idle();  // put sx126x into standby
     // do some basic CAD (blocks for ~12780 micros (on SF 10)!)
     bool activity = (((CustomSX1262 *)_radio)->scanChannel() == RADIOLIB_LORA_DETECTED);
-    idle();
-
+    if (activity) {
+      startRecv();
+    } else {
+      idle();
+    }
     return activity;
   }
   float getLastRSSI() const override { return ((CustomSX1262 *)_radio)->getRSSI(); }

src/helpers/CustomSX1268Wrapper.h

@@ -12,8 +12,11 @@ public:
     idle();  // put sx126x into standby
     // do some basic CAD (blocks for ~12780 micros (on SF 10)!)
     bool activity = (((CustomSX1268 *)_radio)->scanChannel() == RADIOLIB_LORA_DETECTED);
-    idle();
-
+    if (activity) {
+      startRecv();
+    } else {
+      idle();
+    }
     return activity;
   }
   float getLastRSSI() const override { return ((CustomSX1268 *)_radio)->getRSSI(); }

src/helpers/CustomSX1276Wrapper.h

@@ -12,8 +12,11 @@ public:
     idle();  // put into standby
     // do some basic CAD (blocks for ~12780 micros (on SF 10)!)
     bool activity = (((CustomSX1276 *)_radio)->tryScanChannel() == RADIOLIB_PREAMBLE_DETECTED);
-    idle();
-
+    if (activity) {
+      startRecv();
+    } else {
+      idle();
+    }
     return activity;
   }
   float getLastRSSI() const override { return ((CustomSX1276 *)_radio)->getRSSI(); }

src/helpers/RadioLibWrappers.cpp

@@ -35,6 +35,15 @@ void RadioLibWrapper::idle() {
   state = STATE_IDLE;   // need another startReceive()
 }
 
+void RadioLibWrapper::startRecv() {
+  int err = _radio->startReceive();
+  if (err == RADIOLIB_ERR_NONE) {
+    state = STATE_RX;
+  } else {
+    MESH_DEBUG_PRINTLN("RadioLibWrapper: error: startReceive(%d)", err);
+  }
+}
+
 int RadioLibWrapper::recvRaw(uint8_t* bytes, int sz) {
   if (state & STATE_INT_READY) {
     int len = _radio->getPacketLength();
@@ -54,10 +63,11 @@ int RadioLibWrapper::recvRaw(uint8_t* bytes, int sz) {
 
   if (state != STATE_RX) {
     int err = _radio->startReceive();
-    if (err != RADIOLIB_ERR_NONE) {
+    if (err == RADIOLIB_ERR_NONE) {
+      state = STATE_RX;
+    } else {
       MESH_DEBUG_PRINTLN("RadioLibWrapper: error: startReceive(%d)", err);
     }
-    state = STATE_RX;
   }
   return 0;
 }

src/helpers/RadioLibWrappers.h

@@ -10,6 +10,7 @@ protected:
   uint32_t n_recv, n_sent;
 
   void idle();
+  void startRecv();
   float packetScoreInt(float snr, int sf, int packet_len);
 
 public: