From b4076ca23493f3b1a3a81c95e6cf21affa3850b3 Mon Sep 17 00:00:00 2001 From: Wessel Nieboer Date: Wed, 18 Feb 2026 01:16:52 +0100 Subject: [PATCH 1/4] Use hardware channel activity detection for checking interference --- examples/companion_radio/MyMesh.cpp | 2 +- examples/simple_repeater/MyMesh.cpp | 2 +- examples/simple_room_server/MyMesh.cpp | 2 +- examples/simple_sensor/SensorMesh.cpp | 2 +- src/helpers/radiolib/RadioLibWrappers.cpp | 13 ++++++++++--- src/helpers/radiolib/RadioLibWrappers.h | 3 ++- 6 files changed, 16 insertions(+), 8 deletions(-) diff --git a/examples/companion_radio/MyMesh.cpp b/examples/companion_radio/MyMesh.cpp index e8c1914bad..7d621d53b4 100644 --- a/examples/companion_radio/MyMesh.cpp +++ b/examples/companion_radio/MyMesh.cpp @@ -258,7 +258,7 @@ float MyMesh::getAirtimeBudgetFactor() const { } int MyMesh::getInterferenceThreshold() const { - return 0; // disabled for now, until currentRSSI() problem is resolved + return 1; // non-zero enables hardware CAD (Channel Activity Detection) before TX } int MyMesh::calcRxDelay(float score, uint32_t air_time) const { diff --git a/examples/simple_repeater/MyMesh.cpp b/examples/simple_repeater/MyMesh.cpp index 666f79fc5c..13dd916892 100644 --- a/examples/simple_repeater/MyMesh.cpp +++ b/examples/simple_repeater/MyMesh.cpp @@ -886,7 +886,7 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc _prefs.advert_interval = 1; // default to 2 minutes for NEW installs _prefs.flood_advert_interval = 12; // 12 hours _prefs.flood_max = 64; - _prefs.interference_threshold = 0; // disabled + _prefs.interference_threshold = 1; // non-zero enables hardware CAD before TX // bridge defaults _prefs.bridge_enabled = 1; // enabled diff --git a/examples/simple_room_server/MyMesh.cpp b/examples/simple_room_server/MyMesh.cpp index 145fb0fd9f..78488bf569 100644 --- a/examples/simple_room_server/MyMesh.cpp +++ b/examples/simple_room_server/MyMesh.cpp @@ -643,7 +643,7 @@ MyMesh::MyMesh(mesh::MainBoard &board, mesh::Radio &radio, mesh::MillisecondCloc _prefs.advert_interval = 1; // default to 2 minutes for NEW installs _prefs.flood_advert_interval = 12; // 12 hours _prefs.flood_max = 64; - _prefs.interference_threshold = 0; // disabled + _prefs.interference_threshold = 1; // non-zero enables hardware CAD before TX #ifdef ROOM_PASSWORD StrHelper::strncpy(_prefs.guest_password, ROOM_PASSWORD, sizeof(_prefs.guest_password)); #endif diff --git a/examples/simple_sensor/SensorMesh.cpp b/examples/simple_sensor/SensorMesh.cpp index b8fe1e579c..05b2952657 100644 --- a/examples/simple_sensor/SensorMesh.cpp +++ b/examples/simple_sensor/SensorMesh.cpp @@ -725,7 +725,7 @@ SensorMesh::SensorMesh(mesh::MainBoard& board, mesh::Radio& radio, mesh::Millise _prefs.flood_advert_interval = 0; // disabled _prefs.disable_fwd = true; _prefs.flood_max = 64; - _prefs.interference_threshold = 0; // disabled + _prefs.interference_threshold = 1; // non-zero enables hardware CAD before TX // GPS defaults _prefs.gps_enabled = 0; diff --git a/src/helpers/radiolib/RadioLibWrappers.cpp b/src/helpers/radiolib/RadioLibWrappers.cpp index 85f3a935db..62856cb53e 100644 --- a/src/helpers/radiolib/RadioLibWrappers.cpp +++ b/src/helpers/radiolib/RadioLibWrappers.cpp @@ -170,10 +170,17 @@ 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; + if (_threshold == 0) return false; // interference check is disabled + + int16_t result = performChannelScan(); + // scanChannel() leaves radio in standby — restart RX regardless of result + startRecv(); + return (result == RADIOLIB_LORA_DETECTED); } float RadioLibWrapper::getLastRSSI() const { diff --git a/src/helpers/radiolib/RadioLibWrappers.h b/src/helpers/radiolib/RadioLibWrappers.h index ff951aaa47..89c403927c 100644 --- a/src/helpers/radiolib/RadioLibWrappers.h +++ b/src/helpers/radiolib/RadioLibWrappers.h @@ -32,7 +32,7 @@ class RadioLibWrapper : public mesh::Radio { bool isInRecvMode() const override; bool isChannelActive(); - bool isReceiving() override { + bool isReceiving() override { if (isReceivingPacket()) return true; return isChannelActive(); @@ -42,6 +42,7 @@ class RadioLibWrapper : public mesh::Radio { 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; From 8f3b409dbe06b140e0a19557ad56d2b4fe2a0be1 Mon Sep 17 00:00:00 2001 From: Wessel Nieboer Date: Sun, 22 Feb 2026 16:05:18 +0100 Subject: [PATCH 2/4] Also return busy if preamble detected --- src/helpers/radiolib/RadioLibWrappers.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/helpers/radiolib/RadioLibWrappers.cpp b/src/helpers/radiolib/RadioLibWrappers.cpp index 62856cb53e..d13c1fadab 100644 --- a/src/helpers/radiolib/RadioLibWrappers.cpp +++ b/src/helpers/radiolib/RadioLibWrappers.cpp @@ -180,7 +180,7 @@ bool RadioLibWrapper::isChannelActive() { int16_t result = performChannelScan(); // scanChannel() leaves radio in standby — restart RX regardless of result startRecv(); - return (result == RADIOLIB_LORA_DETECTED); + return (result == RADIOLIB_LORA_DETECTED || result == RADIOLIB_PREAMBLE_DETECTED); } float RadioLibWrapper::getLastRSSI() const { From 78c29a0900a1b36e2a057eab0a4491b3a7e0b440 Mon Sep 17 00:00:00 2001 From: Wessel Nieboer Date: Sun, 22 Feb 2026 16:08:04 +0100 Subject: [PATCH 3/4] Just check for not channel free --- src/helpers/radiolib/RadioLibWrappers.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/helpers/radiolib/RadioLibWrappers.cpp b/src/helpers/radiolib/RadioLibWrappers.cpp index d13c1fadab..ce9bab06a3 100644 --- a/src/helpers/radiolib/RadioLibWrappers.cpp +++ b/src/helpers/radiolib/RadioLibWrappers.cpp @@ -180,7 +180,7 @@ bool RadioLibWrapper::isChannelActive() { int16_t result = performChannelScan(); // scanChannel() leaves radio in standby — restart RX regardless of result startRecv(); - return (result == RADIOLIB_LORA_DETECTED || result == RADIOLIB_PREAMBLE_DETECTED); + return result != RADIOLIB_CHANNEL_FREE; } float RadioLibWrapper::getLastRSSI() const { From 2db6d4ef5ded657742a436624c9fb59aaa4f5d67 Mon Sep 17 00:00:00 2001 From: Wessel Nieboer Date: Fri, 6 Mar 2026 04:09:05 +0100 Subject: [PATCH 4/4] Prevent packet errors from growing --- src/helpers/radiolib/RadioLibWrappers.cpp | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/helpers/radiolib/RadioLibWrappers.cpp b/src/helpers/radiolib/RadioLibWrappers.cpp index ce9bab06a3..df5033d80c 100644 --- a/src/helpers/radiolib/RadioLibWrappers.cpp +++ b/src/helpers/radiolib/RadioLibWrappers.cpp @@ -178,7 +178,10 @@ bool RadioLibWrapper::isChannelActive() { if (_threshold == 0) return false; // interference check is disabled int16_t result = performChannelScan(); - // scanChannel() leaves radio in standby — restart RX regardless of result + // 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(); return result != RADIOLIB_CHANNEL_FREE; }