Merge pull request #1727 from weebl2000/use-hardware-channel-activity-detection

Use hardware channel activity detection for checking interference

docs/cli_commands.md

@@ -263,6 +263,20 @@ This document provides an overview of CLI commands that can be sent to MeshCore
 
 ---
 
+#### View or change the LoRa FEM receive-path gain state on supported boards
+**Usage:**
+- `get radio.fem.rxgain`
+- `set radio.fem.rxgain <state>`
+
+**Parameters:**
+- `state`: `on`|`off`
+
+**Notes:**
+- This controls the external LoRa FEM receive-path LNA where the board supports it.
+- This is separate from `radio.rxgain`, which controls the radio chip receive gain mode.
+
+---
+
 ### System
 
 #### View or change this node's name
@@ -564,6 +578,20 @@ This document provides an overview of CLI commands that can be sent to MeshCore
 
 ---
 
+#### Enable or disable hardware Channel Activity Detection (CAD)
+**Usage:**
+- `get cad`
+- `set cad <on|off>`
+
+**Description:** When enabled, the radio performs a hardware Channel Activity Detection scan before transmitting and defers if the channel is busy. Runs independently of `int.thresh` — either, both, or none may be active.
+
+**Parameters:**
+- `on|off`: Enable or disable hardware CAD
+
+**Default:** `off`
+
+---
+
 #### View or change the AGC Reset Interval
 **Usage:**
 - `get agc.reset.interval`

examples/companion_radio/MyMesh.cpp

@@ -261,6 +261,9 @@ float MyMesh::getAirtimeBudgetFactor() const {
 int MyMesh::getInterferenceThreshold() const {
   return 0; // disabled for now, until currentRSSI() problem is resolved
 }
+bool MyMesh::getCADEnabled() const {
+  return true; // hardware CAD before TX (no CLI toggle on companion; enabled by default)
+}
 
 int MyMesh::calcRxDelay(float score, uint32_t air_time) const {
   if (_prefs.rx_delay_base <= 0.0f) return 0;
@@ -854,7 +857,7 @@ void MyMesh::onSendTimeout() {}
 
 MyMesh::MyMesh(mesh::Radio &radio, mesh::RNG &rng, mesh::RTCClock &rtc, SimpleMeshTables &tables, DataStore& store, AbstractUITask* ui)
     : BaseChatMesh(radio, *new ArduinoMillis(), rng, rtc, *new StaticPoolPacketManager(16), tables),
-      _serial(NULL), telemetry(MAX_PACKET_PAYLOAD - 4), _store(&store), _ui(ui) {
+      _serial(NULL), telemetry(MAX_PACKET_PAYLOAD - 4), _store(&store), _ui(ui), _iter(0) {
   _iter_started = false;
   _cli_rescue = false;
   offline_queue_len = 0;
@@ -1542,6 +1545,7 @@ void MyMesh::handleCmdFrame(size_t len) {
       memcpy(anon.id.pub_key, pub_key, PUB_KEY_SIZE);
       anon.out_path_len = 0;   // default to zero-hop direct
       anon.type = ADV_TYPE_NONE;  // unknown
+      anon.lastmod = getRTCClock()->getCurrentTime();
 
       if (addContact(anon)) recipient = &anon;
     }
@@ -1981,6 +1985,7 @@ void MyMesh::handleCmdFrame(size_t len) {
         sendPacket(pkt, priority, 0);
         writeOKFrame();
       } else {
+        releasePacket(pkt);
         writeErrFrame(ERR_CODE_ILLEGAL_ARG);
       }
     } else {
@@ -2186,15 +2191,7 @@ void MyMesh::checkSerialInterface() {
              && !_serial->isWriteBusy() // don't spam the Serial Interface too quickly!
   ) {
     ContactInfo contact;
-    bool found = false;
-    while (_iter.hasNext(this, contact)) {
-      if (contact.type != ADV_TYPE_NONE) {
-        found = true;
-        break;
-      }
-    }
-
-    if (found) {
+    if (_iter.hasNext(this, contact)) {
       if (contact.lastmod > _iter_filter_since) { // apply the 'since' filter
         writeContactRespFrame(RESP_CODE_CONTACT, contact);
         if (contact.lastmod > _most_recent_lastmod) {

examples/companion_radio/MyMesh.h

@@ -105,6 +105,7 @@ public:
 protected:
   float getAirtimeBudgetFactor() const override;
   int getInterferenceThreshold() const override;
+  bool getCADEnabled() const override;
   int calcRxDelay(float score, uint32_t air_time) const override;
   uint32_t getRetransmitDelay(const mesh::Packet *packet) override;
   uint32_t getDirectRetransmitDelay(const mesh::Packet *packet) override;

examples/simple_repeater/MyMesh.cpp

@@ -893,6 +893,7 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc
   _prefs.flood_max_unscoped = 64;
   _prefs.flood_max_advert = 8;
   _prefs.interference_threshold = 0; // disabled
+  _prefs.cad_enabled = 0;            // hardware CAD before TX (off by default; 'set cad on')
 
   // bridge defaults
   _prefs.bridge_enabled = 1;    // enabled
@@ -917,6 +918,7 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc
   _prefs.rx_boosted_gain = 1; // enabled by default;
 #endif
 #endif
+  _prefs.radio_fem_rxgain = 1;
 
   pending_discover_tag = 0;
   pending_discover_until = 0;
@@ -965,6 +967,7 @@ void MyMesh::begin(FILESYSTEM *fs) {
   radio_driver.setRxBoostedGainMode(_prefs.rx_boosted_gain);
   MESH_DEBUG_PRINTLN("RX Boosted Gain Mode: %s",
                      radio_driver.getRxBoostedGainMode() ? "Enabled" : "Disabled");
+  board.setLoRaFemLnaEnabled(_prefs.radio_fem_rxgain);
 
   updateAdvertTimer();
   updateFloodAdvertTimer();

examples/simple_repeater/MyMesh.h

@@ -150,6 +150,9 @@ protected:
   int getInterferenceThreshold() const override {
     return _prefs.interference_threshold;
   }
+  bool getCADEnabled() const override {
+    return _prefs.cad_enabled;
+  }
   int getAGCResetInterval() const override {
     return ((int)_prefs.agc_reset_interval) * 4000;   // milliseconds
   }

examples/simple_repeater/UITask.cpp

@@ -41,7 +41,8 @@ void UITask::begin(NodePrefs* node_prefs, const char* build_date, const char* fi
   }
 
   // v1.2.3 (1 Jan 2025)
-  sprintf(_version_info, "%s (%s)", version, build_date);
+  snprintf(_version_info, sizeof(_version_info), "%s (%s)", version, build_date);
+  free(version);
 }
 
 void UITask::renderCurrScreen() {

examples/simple_room_server/MyMesh.cpp

@@ -650,6 +650,7 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc
   _prefs.flood_max_unscoped = 64;
   _prefs.flood_max_advert = 8;
   _prefs.interference_threshold = 0; // disabled
+  _prefs.cad_enabled = 0;            // hardware CAD before TX (off by default; 'set cad on')
 #ifdef ROOM_PASSWORD
   StrHelper::strncpy(_prefs.guest_password, ROOM_PASSWORD, sizeof(_prefs.guest_password));
 #endif
@@ -658,6 +659,7 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc
   _prefs.gps_enabled = 0;
   _prefs.gps_interval = 0;
   _prefs.advert_loc_policy = ADVERT_LOC_PREFS;
+  _prefs.radio_fem_rxgain = 1;
 
   next_post_idx = 0;
   next_client_idx = 0;
@@ -699,6 +701,7 @@ void MyMesh::begin(FILESYSTEM *fs) {
 
   radio_driver.setParams(_prefs.freq, _prefs.bw, _prefs.sf, _prefs.cr);
   radio_driver.setTxPower(_prefs.tx_power_dbm);
+  board.setLoRaFemLnaEnabled(_prefs.radio_fem_rxgain);
 
   updateAdvertTimer();
   updateFloodAdvertTimer();

examples/simple_room_server/MyMesh.h

@@ -144,6 +144,9 @@ protected:
   int getInterferenceThreshold() const override {
     return _prefs.interference_threshold;
   }
+  bool getCADEnabled() const override {
+    return _prefs.cad_enabled;
+  }
   int getAGCResetInterval() const override {
     return ((int)_prefs.agc_reset_interval) * 4000;   // milliseconds
   }

examples/simple_room_server/UITask.cpp

@@ -41,7 +41,8 @@ void UITask::begin(NodePrefs* node_prefs, const char* build_date, const char* fi
   }
 
   // v1.2.3 (1 Jan 2025)
-  sprintf(_version_info, "%s (%s)", version, build_date);
+  snprintf(_version_info, sizeof(_version_info), "%s (%s)", version, build_date);
+  free(version);
 }
 
 void UITask::renderCurrScreen() {

examples/simple_secure_chat/main.cpp

@@ -135,7 +135,7 @@ class MyMesh : public BaseChatMesh, ContactVisitor {
     File file = _fs->open("/contacts", "w", true);
 #endif
     if (file) {
-      ContactsIterator iter;
+      ContactsIterator iter = startContactsIterator();
       ContactInfo c;
       uint8_t unused = 0;
       uint32_t reserved = 0;

examples/simple_sensor/SensorMesh.cpp

@@ -323,6 +323,9 @@ uint32_t SensorMesh::getDirectRetransmitDelay(const mesh::Packet* packet) {
 int SensorMesh::getInterferenceThreshold() const {
   return _prefs.interference_threshold;
 }
+bool SensorMesh::getCADEnabled() const {
+  return _prefs.cad_enabled;
+}
 int SensorMesh::getAGCResetInterval() const {
   return ((int)_prefs.agc_reset_interval) * 4000;   // milliseconds
 }
@@ -726,11 +729,13 @@ SensorMesh::SensorMesh(mesh::MainBoard& board, mesh::Radio& radio, mesh::Millise
   _prefs.disable_fwd = true;
   _prefs.flood_max = 64;
   _prefs.interference_threshold = 0;  // disabled
+  _prefs.cad_enabled = 0;             // hardware CAD before TX (off by default; 'set cad on')
 
   // GPS defaults
   _prefs.gps_enabled = 0;
   _prefs.gps_interval = 0;
   _prefs.advert_loc_policy = ADVERT_LOC_PREFS;
+  _prefs.radio_fem_rxgain = 1;
 
   memset(default_scope.key, 0, sizeof(default_scope.key));
 }
@@ -766,6 +771,7 @@ void SensorMesh::begin(FILESYSTEM* fs) {
 
   radio_driver.setParams(_prefs.freq, _prefs.bw, _prefs.sf, _prefs.cr);
   radio_driver.setTxPower(_prefs.tx_power_dbm);
+  board.setLoRaFemLnaEnabled(_prefs.radio_fem_rxgain);
 
   updateAdvertTimer();
   updateFloodAdvertTimer();

examples/simple_sensor/SensorMesh.h

@@ -120,6 +120,7 @@ protected:
   uint32_t getRetransmitDelay(const mesh::Packet* packet) override;
   uint32_t getDirectRetransmitDelay(const mesh::Packet* packet) override;
   int getInterferenceThreshold() const override;
+  bool getCADEnabled() const override;
   int getAGCResetInterval() const override;
   void onAnonDataRecv(mesh::Packet* packet, const uint8_t* secret, const mesh::Identity& sender, uint8_t* data, size_t len) override;
   int searchPeersByHash(const uint8_t* hash) override;

examples/simple_sensor/UITask.cpp

@@ -41,7 +41,8 @@ void UITask::begin(NodePrefs* node_prefs, const char* build_date, const char* fi
   }
 
   // v1.2.3 (1 Jan 2025)
-  sprintf(_version_info, "%s (%s)", version, build_date);
+  snprintf(_version_info, sizeof(_version_info), "%s (%s)", version, build_date);
+  free(version);
 }
 
 void UITask::renderCurrScreen() {

src/Dispatcher.cpp

@@ -66,6 +66,7 @@ uint32_t Dispatcher::getCADFailMaxDuration() const {
 void Dispatcher::loop() {
   if (millisHasNowPassed(next_floor_calib_time)) {
     _radio->triggerNoiseFloorCalibrate(getInterferenceThreshold());
+    _radio->setCADEnabled(getCADEnabled());
     next_floor_calib_time = futureMillis(NOISE_FLOOR_CALIB_INTERVAL);
   }
   _radio->loop();

src/Dispatcher.h

@@ -65,6 +65,8 @@ public:
 
   virtual void triggerNoiseFloorCalibrate(int threshold) { }
 
+  virtual void setCADEnabled(bool enable) { }
+
   virtual void resetAGC() { }
 
   virtual bool isInRecvMode() const = 0;
@@ -166,6 +168,7 @@ protected:
   virtual uint32_t getCADFailRetryDelay() const;
   virtual uint32_t getCADFailMaxDuration() const;
   virtual int getInterferenceThreshold() const { return 0; }    // disabled by default
+  virtual bool getCADEnabled() const { return false; }    // hardware CAD disabled by default
   virtual int getAGCResetInterval() const { return 0; }    // disabled by default
   virtual unsigned long getDutyCycleWindowMs() const { return 3600000; }
 

src/Mesh.cpp

@@ -155,6 +155,10 @@ DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
               if (pkt->getPayloadType() == PAYLOAD_TYPE_PATH) {
                 int k = 0;
                 uint8_t path_len = data[k++];
+                if (!Packet::isValidPathLen(path_len)) {
+                  MESH_DEBUG_PRINTLN("%s PAYLOAD_TYPE_PATH, bad path_len: %u", getLogDateTime(), (uint32_t)path_len);
+                  break;   // reject bad encoding
+                }
                 uint8_t hash_size = (path_len >> 6) + 1;
                 uint8_t hash_count = path_len & 63;
                 uint8_t* path = &data[k]; k += hash_size*hash_count;

src/MeshCore.h

@@ -64,6 +64,9 @@ public:
   virtual uint8_t getStartupReason() const = 0;
   virtual bool getBootloaderVersion(char* version, size_t max_len) { return false; }
   virtual bool startOTAUpdate(const char* id, char reply[]) { return false; }   // not supported
+  virtual bool setLoRaFemLnaEnabled(bool enable) { return false; }
+  virtual bool canControlLoRaFemLna() const { return false; }
+  virtual bool isLoRaFemLnaEnabled() const { return false; }
 
   // Power management interface (boards with power management override these)
   virtual bool isExternalPowered() { return false; }

src/helpers/BaseChatMesh.cpp

@@ -68,29 +68,36 @@ void BaseChatMesh::bootstrapRTCfromContacts() {
 }
 
 ContactInfo* BaseChatMesh::allocateContactSlot(bool transient_only) {
-  if (num_contacts < MAX_CONTACTS) {
-    return &contacts[num_contacts++];
-  } else if (transient_only || shouldOverwriteWhenFull()) {
-    // Find oldest non-favourite contact by oldest lastmod timestamp
-    int oldest_idx = -1;
-    uint32_t oldest_lastmod = 0xFFFFFFFF;
-    for (int i = 0; i < num_contacts; i++) {
-      if (transient_only) {
-        if (contacts[i].type == ADV_TYPE_NONE && contacts[i].lastmod < oldest_lastmod) {
-          oldest_lastmod = contacts[i].lastmod;
-          oldest_idx = i;
-        }
-      } else {
+  int oldest_idx = -1;
+  uint32_t oldest_lastmod = 0xFFFFFFFF;
+  if (transient_only) {
+    // only allocate from first N
+    for (int i = 0; i < MAX_ANON_CONTACTS; i++) {
+      if (contacts[i].type == ADV_TYPE_NONE && contacts[i].lastmod < oldest_lastmod) {
+        oldest_lastmod = contacts[i].lastmod;
+        oldest_idx = i;
+      }
+    }
+    if (oldest_idx >= 0) {
+      // NOTE: do NOT call onContactOverwrite()
+      return &contacts[oldest_idx];
+    }
+  } else {
+    if (num_contacts < MAX_ANON_CONTACTS+MAX_CONTACTS) {
+      return &contacts[num_contacts++];
+    } else if (shouldOverwriteWhenFull()) {
+      // Find oldest non-favourite contact by oldest lastmod timestamp
+      for (int i = MAX_ANON_CONTACTS; i < num_contacts; i++) {
         bool is_favourite = (contacts[i].flags & 0x01) != 0;
-        if (!is_favourite && contacts[i].lastmod < oldest_lastmod && contacts[i].type != ADV_TYPE_NONE) {
+        if (!is_favourite && contacts[i].lastmod < oldest_lastmod) {
           oldest_lastmod = contacts[i].lastmod;
           oldest_idx = i;
         }
       }
-    }
-    if (oldest_idx >= 0) {
-      onContactOverwrite(contacts[oldest_idx].id.pub_key);
-      return &contacts[oldest_idx];
+      if (oldest_idx >= 0) {
+        onContactOverwrite(contacts[oldest_idx].id.pub_key);
+        return &contacts[oldest_idx];
+      }
     }
   }
   return NULL; // no space, no overwrite or all contacts are all favourites
@@ -139,6 +146,11 @@ void BaseChatMesh::onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id,
     packet->header = save;
   }
 
+  if (from && from->type == ADV_TYPE_NONE) {   // already in contacts, but from a temporary ANON_REQ ?
+    memset(from, 0, sizeof(*from));  // clear the anon/temp slot
+    from = NULL;  // do normal 'add' flow
+  }
+
   bool is_new = false; // true = not in contacts[], false = exists in contacts[]
   if (from == NULL) {
     if (!shouldAutoAddContactType(parser.getType())) {
@@ -930,11 +942,11 @@ bool BaseChatMesh::getContactByIdx(uint32_t idx, ContactInfo& contact) {
 }
 
 ContactsIterator BaseChatMesh::startContactsIterator() {
-  return ContactsIterator();
+  return ContactsIterator(MAX_ANON_CONTACTS);   // start at offset, skip the anon entries
 }
 
 bool ContactsIterator::hasNext(const BaseChatMesh* mesh, ContactInfo& dest) {
-  if (next_idx >= mesh->getNumContacts()) return false;
+  if (next_idx >= mesh->getTotalContactSlots()) return false;
 
   dest = mesh->contacts[next_idx++];
   return true;

src/helpers/BaseChatMesh.h

@@ -28,8 +28,9 @@ public:
 class BaseChatMesh;
 
 class ContactsIterator {
-  int next_idx = 0;
+  int next_idx;
 public:
+  ContactsIterator(int start) { next_idx = start; }
   bool hasNext(const BaseChatMesh* mesh, ContactInfo& dest);
 };
 
@@ -79,8 +80,9 @@ class BaseChatMesh : public mesh::Mesh {
 protected:
   BaseChatMesh(mesh::Radio& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc, mesh::PacketManager& mgr, mesh::MeshTables& tables)
       : mesh::Mesh(radio, ms, rng, rtc, mgr, tables)
-  { 
-    num_contacts = 0;
+  {
+    resetContacts();
+
   #ifdef MAX_GROUP_CHANNELS
     memset(channels, 0, sizeof(channels));
     num_channels = 0;
@@ -91,7 +93,11 @@ protected:
   }
 
   void bootstrapRTCfromContacts();
-  void resetContacts() { num_contacts = 0; }
+
+  void resetContacts() {
+    memset(contacts, 0, sizeof(contacts[0])*MAX_ANON_CONTACTS);   // set all to have type = ADV_TYPE_NONE(0)
+    num_contacts = MAX_ANON_CONTACTS;  // seed the first contacts for anon requests
+  }
   void populateContactFromAdvert(ContactInfo& ci, const mesh::Identity& id, const AdvertDataParser& parser, uint32_t timestamp);
   ContactInfo* allocateContactSlot(bool transient_only=false); // helper to find slot for new contact
 
@@ -166,7 +172,8 @@ public:
   ContactInfo* lookupContactByPubKey(const uint8_t* pub_key, int prefix_len);
   bool  removeContact(ContactInfo& contact);
   bool  addContact(const ContactInfo& contact);
-  int getNumContacts() const { return num_contacts; }
+  int getTotalContactSlots() const { return num_contacts; }
+  int getNumContacts() const { return num_contacts - MAX_ANON_CONTACTS; }  // don't include the reserved slots at start
   bool getContactByIdx(uint32_t idx, ContactInfo& contact);
   ContactsIterator startContactsIterator();
   ChannelDetails* addChannel(const char* name, const char* psk_base64);

src/helpers/CommonCLI.cpp

@@ -88,10 +88,12 @@ void CommonCLI::loadPrefsInt(FILESYSTEM* fs, const char* filename) {
     file.read((uint8_t *)&_prefs->discovery_mod_timestamp, sizeof(_prefs->discovery_mod_timestamp)); // 162
     file.read((uint8_t *)&_prefs->adc_multiplier, sizeof(_prefs->adc_multiplier));                 // 166
     file.read((uint8_t *)_prefs->owner_info, sizeof(_prefs->owner_info));                          // 170
-    file.read((uint8_t *)&_prefs->rx_boosted_gain, sizeof(_prefs->rx_boosted_gain));              // 290
-    file.read((uint8_t *)&_prefs->flood_max_unscoped, sizeof(_prefs->flood_max_unscoped));   // 291
-    file.read((uint8_t *)&_prefs->flood_max_advert, sizeof(_prefs->flood_max_advert));       // 292
-    // next: 293
+    file.read((uint8_t *)&_prefs->rx_boosted_gain, sizeof(_prefs->rx_boosted_gain));               // 290
+    file.read((uint8_t *)&_prefs->flood_max_unscoped, sizeof(_prefs->flood_max_unscoped));         // 291
+    file.read((uint8_t *)&_prefs->flood_max_advert, sizeof(_prefs->flood_max_advert));             // 292
+    file.read((uint8_t *)&_prefs->radio_fem_rxgain, sizeof(_prefs->radio_fem_rxgain));             // 293
+    file.read((uint8_t *)&_prefs->cad_enabled, sizeof(_prefs->cad_enabled));                       // 294
+    // next: 295
 
     // sanitise bad pref values
     _prefs->rx_delay_base = constrain(_prefs->rx_delay_base, 0, 20.0f);
@@ -121,6 +123,8 @@ void CommonCLI::loadPrefsInt(FILESYSTEM* fs, const char* filename) {
 
     // sanitise settings
     _prefs->rx_boosted_gain = constrain(_prefs->rx_boosted_gain, 0, 1); // boolean
+    _prefs->radio_fem_rxgain = constrain(_prefs->radio_fem_rxgain, 0, 1); // boolean
+    _prefs->cad_enabled = constrain(_prefs->cad_enabled, 0, 1); // boolean
 
     file.close();
   }
@@ -181,10 +185,12 @@ void CommonCLI::savePrefs(FILESYSTEM* fs) {
     file.write((uint8_t *)&_prefs->discovery_mod_timestamp, sizeof(_prefs->discovery_mod_timestamp)); // 162
     file.write((uint8_t *)&_prefs->adc_multiplier, sizeof(_prefs->adc_multiplier));                 // 166
     file.write((uint8_t *)_prefs->owner_info, sizeof(_prefs->owner_info));                          // 170
-    file.write((uint8_t *)&_prefs->rx_boosted_gain, sizeof(_prefs->rx_boosted_gain));              // 290
-    file.write((uint8_t *)&_prefs->flood_max_unscoped, sizeof(_prefs->flood_max_unscoped));   // 291
-    file.write((uint8_t *)&_prefs->flood_max_advert, sizeof(_prefs->flood_max_advert));       // 292
-    // next: 293
+    file.write((uint8_t *)&_prefs->rx_boosted_gain, sizeof(_prefs->rx_boosted_gain));               // 290
+    file.write((uint8_t *)&_prefs->flood_max_unscoped, sizeof(_prefs->flood_max_unscoped));         // 291
+    file.write((uint8_t *)&_prefs->flood_max_advert, sizeof(_prefs->flood_max_advert));             // 292
+    file.write((uint8_t *)&_prefs->radio_fem_rxgain, sizeof(_prefs->radio_fem_rxgain));             // 293
+    file.write((uint8_t *)&_prefs->cad_enabled, sizeof(_prefs->cad_enabled));                       // 294
+    // next: 295
 
     file.close();
   }
@@ -500,6 +506,10 @@ void CommonCLI::handleSetCmd(uint32_t sender_timestamp, char* command, char* rep
     _prefs->interference_threshold = atoi(&config[11]);
     savePrefs();
     strcpy(reply, "OK");
+  } else if (memcmp(config, "cad ", 4) == 0) {
+    _prefs->cad_enabled = memcmp(&config[4], "on", 2) == 0;
+    savePrefs();
+    strcpy(reply, "OK");
   } else if (memcmp(config, "agc.reset.interval ", 19) == 0) {
     _prefs->agc_reset_interval = atoi(&config[19]) / 4;
     savePrefs();
@@ -568,6 +578,28 @@ void CommonCLI::handleSetCmd(uint32_t sender_timestamp, char* command, char* rep
     savePrefs();
     _callbacks->setRxBoostedGain(_prefs->rx_boosted_gain);
 #endif
+  } else if (memcmp(config, "radio.fem.rxgain ", 17) == 0) {
+    if (!_board->canControlLoRaFemLna()) {
+      strcpy(reply, "Error: unsupported");
+    } else if (memcmp(&config[17], "on", 2) == 0) {
+      if (_board->setLoRaFemLnaEnabled(true)) {
+        _prefs->radio_fem_rxgain = 1;
+        savePrefs();
+        strcpy(reply, "OK - LoRa FEM RX gain on");
+      } else {
+        strcpy(reply, "Error: failed to apply LoRa FEM RX gain");
+      }
+    } else if (memcmp(&config[17], "off", 3) == 0) {
+      if (_board->setLoRaFemLnaEnabled(false)) {
+        _prefs->radio_fem_rxgain = 0;
+        savePrefs();
+        strcpy(reply, "OK - LoRa FEM RX gain off");
+      } else {
+        strcpy(reply, "Error: failed to apply LoRa FEM RX gain");
+      }
+    } else {
+      strcpy(reply, "Error: state must be on or off");
+    }
   } else if (memcmp(config, "radio ", 6) == 0) {
     strcpy(tmp, &config[6]);
     const char *parts[4];
@@ -757,7 +789,7 @@ void CommonCLI::handleSetCmd(uint32_t sender_timestamp, char* command, char* rep
       }
     } else {
       _prefs->adc_multiplier = 0.0f;
-      strcpy(reply, "Error: unsupported by this board");
+      strcpy(reply, "Error: unsupported");
     };
   } else {
     strcpy(reply, "unknown config: ");
@@ -776,6 +808,8 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
     sprintf(reply, "> %s", StrHelper::ftoa(_prefs->airtime_factor));
   } 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");
   } 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) {
@@ -805,6 +839,12 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
   } else if (memcmp(config, "radio.rxgain", 12) == 0) {
     sprintf(reply, "> %s", _prefs->rx_boosted_gain ? "on" : "off");
 #endif
+  } else if (memcmp(config, "radio.fem.rxgain", 16) == 0) {
+    if (!_board->canControlLoRaFemLna()) {
+      strcpy(reply, "Error: unsupported");
+    } else {
+      sprintf(reply, "> %s", _board->isLoRaFemLnaEnabled() ? "on" : "off");
+    }
   } else if (memcmp(config, "radio", 5) == 0) {
     char freq[16], bw[16];
     strcpy(freq, StrHelper::ftoa(_prefs->freq));
@@ -890,12 +930,12 @@ void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* rep
           strcpy(reply, "> unknown");
       }
   #else
-      strcpy(reply, "ERROR: unsupported");
+      strcpy(reply, "Error: unsupported");
   #endif
   } else if (memcmp(config, "adc.multiplier", 14) == 0) {
     float adc_mult = _board->getAdcMultiplier();
     if (adc_mult == 0.0f) {
-      strcpy(reply, "Error: unsupported by this board");
+      strcpy(reply, "Error: unsupported");
     } else {
       sprintf(reply, "> %.3f", adc_mult);
     }

src/helpers/CommonCLI.h

@@ -61,8 +61,10 @@ struct NodePrefs { // persisted to file
   float adc_multiplier;
   char owner_info[120];
   uint8_t rx_boosted_gain; // power settings
+  uint8_t radio_fem_rxgain; // LoRa FEM RX gain setting
   uint8_t path_hash_mode;   // which path mode to use when sending
   uint8_t loop_detect;
+  uint8_t cad_enabled;      // hardware Channel Activity Detection before TX (boolean)
 };
 
 class CommonCLICallbacks {

src/helpers/radiolib/RadioLibWrappers.cpp

@@ -36,6 +36,7 @@ void RadioLibWrapper::begin() {
 
   _noise_floor = 0;
   _threshold = 0;
+  _cad_enabled = false;
 
   // start average out some samples
   _num_floor_samples = 0;
@@ -178,10 +179,26 @@ void RadioLibWrapper::onSendFinished() {
   state = STATE_IDLE;
 }
 
+int16_t RadioLibWrapper::performChannelScan() {
+  return _radio->scanChannel();
+}
+
 bool RadioLibWrapper::isChannelActive() {
-  return _threshold == 0 
-          ? false    // interference check is disabled
-          : getCurrentRSSI() > _noise_floor + _threshold;
+  // int.thresh: RSSI-based interference detection (relative to noise floor)
+  if (_threshold != 0 && getCurrentRSSI() > _noise_floor + _threshold) return true;
+
+  // cad: hardware channel activity detection
+  if (_cad_enabled) {
+    int16_t result = performChannelScan();
+    // scanChannel() triggers DIO interrupt (CAD done) which sets STATE_INT_READY
+    // via setFlag() ISR. Clear it before restarting RX so recvRaw() doesn't
+    // try to read a non-existent packet and count a spurious recv error.
+    state = STATE_IDLE;
+    startRecv();
+    if (result != RADIOLIB_CHANNEL_FREE) return true;
+  }
+
+  return false;
 }
 
 float RadioLibWrapper::getLastRSSI() const {

src/helpers/radiolib/RadioLibWrappers.h

@@ -9,6 +9,7 @@ protected:
   mesh::MainBoard* _board;
   uint32_t n_recv, n_sent, n_recv_errors;
   int16_t _noise_floor, _threshold;
+  bool _cad_enabled;
   uint16_t _num_floor_samples;
   int32_t _floor_sample_sum;
   uint8_t _preamble_sf;
@@ -32,7 +33,7 @@ public:
   bool isInRecvMode() const override;
   bool isChannelActive();
 
-  bool isReceiving() override { 
+  bool isReceiving() override {
     if (isReceivingPacket()) return true;
 
     return isChannelActive();
@@ -46,9 +47,11 @@ public:
   virtual uint8_t getSpreadingFactor() const { return LORA_SF; }
   static uint16_t preambleLengthForSF(uint8_t sf) { return sf <= 8 ? 32 : 16; }
   void updatePreamble(uint8_t sf) { _preamble_sf = sf; _radio->setPreambleLength(preambleLengthForSF(sf)); }
+  virtual int16_t performChannelScan();
 
   int getNoiseFloor() const override { return _noise_floor; }
   void triggerNoiseFloorCalibrate(int threshold) override;
+  void setCADEnabled(bool enable) override { _cad_enabled = enable; }
   void resetAGC() override;
 
   void loop() override;

variants/heltec_t096/LoRaFEMControl.h

@@ -12,8 +12,9 @@ class LoRaFEMControl
     void setRxModeEnable(void);
     void setRxModeEnableWhenMCUSleep(void);
     void setLNAEnable(bool enabled);
-    bool isLnaCanControl(void) { return lna_can_control; }
+    bool isLnaCanControl(void) const { return lna_can_control; }
     void setLnaCanControl(bool can_control) { lna_can_control = can_control; }
+    bool isLNAEnabled(void) const { return lna_enabled; }
 
   private:
     bool lna_enabled = false;

variants/heltec_t096/T096Board.cpp

@@ -123,4 +123,22 @@ void T096Board::powerOff() {
 
 const char* T096Board::getManufacturerName() const {
   return "Heltec T096";
-}
+}
+
+bool T096Board::setLoRaFemLnaEnabled(bool enable) {
+  if (!loRaFEMControl.isLnaCanControl()) {
+    return false;
+  }
+
+  loRaFEMControl.setLNAEnable(enable);
+  loRaFEMControl.setRxModeEnable();
+  return true;
+}
+
+bool T096Board::canControlLoRaFemLna() const {
+  return loRaFEMControl.isLnaCanControl();
+}
+
+bool T096Board::isLoRaFemLnaEnabled() const {
+  return loRaFEMControl.isLNAEnabled();
+}

variants/heltec_t096/T096Board.h

@@ -25,4 +25,7 @@ public:
   uint16_t getBattMilliVolts() override;
   const char* getManufacturerName() const override ;
   void powerOff() override;
+  bool setLoRaFemLnaEnabled(bool enable) override;
+  bool canControlLoRaFemLna() const override;
+  bool isLoRaFemLnaEnabled() const override;
 };

variants/heltec_tracker_v2/HeltecTrackerV2Board.cpp

@@ -82,3 +82,21 @@ void HeltecTrackerV2Board::begin() {
   const char* HeltecTrackerV2Board::getManufacturerName() const {
     return "Heltec Tracker V2";
   }
+
+  bool HeltecTrackerV2Board::setLoRaFemLnaEnabled(bool enable) {
+    if (!loRaFEMControl.isLnaCanControl()) {
+      return false;
+    }
+
+    loRaFEMControl.setLNAEnable(enable);
+    loRaFEMControl.setRxModeEnable();
+    return true;
+  }
+
+  bool HeltecTrackerV2Board::canControlLoRaFemLna() const {
+    return loRaFEMControl.isLnaCanControl();
+  }
+
+  bool HeltecTrackerV2Board::isLoRaFemLnaEnabled() const {
+    return loRaFEMControl.isLNAEnabled();
+  }

variants/heltec_tracker_v2/HeltecTrackerV2Board.h

@@ -21,5 +21,8 @@ public:
   void powerOff() override;
   uint16_t getBattMilliVolts() override;
   const char* getManufacturerName() const override ;
+  bool setLoRaFemLnaEnabled(bool enable) override;
+  bool canControlLoRaFemLna() const override;
+  bool isLoRaFemLnaEnabled() const override;
 
 };

variants/heltec_tracker_v2/LoRaFEMControl.h

@@ -12,8 +12,9 @@ class LoRaFEMControl
     void setRxModeEnable(void);
     void setRxModeEnableWhenMCUSleep(void);
     void setLNAEnable(bool enabled);
-    bool isLnaCanControl(void) { return lna_can_control; }
+    bool isLnaCanControl(void) const { return lna_can_control; }
     void setLnaCanControl(bool can_control) { lna_can_control = can_control; }
+    bool isLNAEnabled(void) const { return lna_enabled; }
 
   private:
     bool lna_enabled = false;

variants/heltec_v4/HeltecV4Board.cpp

@@ -83,3 +83,21 @@ void HeltecV4Board::begin() {
     return loRaFEMControl.getFEMType() == KCT8103L_PA ? "Heltec V4.3 OLED" : "Heltec V4 OLED";
 #endif
   }
+
+  bool HeltecV4Board::setLoRaFemLnaEnabled(bool enable) {
+    if (!loRaFEMControl.isLnaCanControl()) {
+      return false;
+    }
+
+    loRaFEMControl.setLNAEnable(enable);
+    loRaFEMControl.setRxModeEnable();
+    return true;
+  }
+
+  bool HeltecV4Board::canControlLoRaFemLna() const {
+    return loRaFEMControl.isLnaCanControl();
+  }
+
+  bool HeltecV4Board::isLoRaFemLnaEnabled() const {
+    return loRaFEMControl.isLNAEnabled();
+  }

variants/heltec_v4/HeltecV4Board.h

@@ -25,6 +25,9 @@ public:
   void onAfterTransmit(void) override;
   void enterDeepSleep(uint32_t secs, int pin_wake_btn = -1);
   void powerOff() override;
+  bool setLoRaFemLnaEnabled(bool enable) override;
+  bool canControlLoRaFemLna() const override;
+  bool isLoRaFemLnaEnabled() const override;
   uint16_t getBattMilliVolts() override;
   bool setAdcMultiplier(float multiplier) override {
     if (multiplier == 0.0f) {

variants/heltec_v4/LoRaFEMControl.h

@@ -18,8 +18,9 @@ class LoRaFEMControl
     void setRxModeEnable(void);
     void setRxModeEnableWhenMCUSleep(void);
     void setLNAEnable(bool enabled);
-    bool isLnaCanControl(void) { return lna_can_control; }
+    bool isLnaCanControl(void) const { return lna_can_control; }
     void setLnaCanControl(bool can_control) { lna_can_control = can_control; }
+    bool isLNAEnabled(void) const { return lna_enabled; }
     LoRaFEMType getFEMType(void) const { return fem_type; }
   private:
     LoRaFEMType fem_type=OTHER_FEM_TYPES;