Implemented adaptive CSMA scheme

diff --git a/Config.h b/Config.h
index ccf19378527438b7c5b0d5566d76974b1b253a58..b1affe38c2812ae998149d13f849287b8a12c28d 100644 (file)
--- a/Config.h
+++ b/Config.h
@@ -290,7 +290,10 @@
        // MCU independent configuration parameters
        const long serial_baudrate  = 115200;
        const int lora_rx_turnaround_ms = 50;
-       const int csma_slot_ms = lora_rx_turnaround_ms;
+       uint8_t csma_p = 0;
+       float csma_p_min = 0.1;
+       float csma_p_max = 0.8;
+       int csma_slot_ms = lora_rx_turnaround_ms;
 
        // SX1276 RSSI offset to get dBm value from
        // packet RSSI register
@@ -311,11 +314,11 @@
        // Operational variables
        bool radio_locked  = true;
        bool radio_online  = false;
-    bool community_fw  = true;
+       bool community_fw  = true;
        bool hw_ready      = false;
-    bool radio_error   = false;
-    bool disp_ready    = false;
-    bool pmu_ready     = false;
+       bool radio_error   = false;
+       bool disp_ready    = false;
+       bool pmu_ready     = false;
        bool promisc       = false;
        bool implicit      = false;
        uint8_t implicit_l = 0;
@@ -370,11 +373,12 @@
        bool stat_signal_detected = false;
        bool stat_signal_synced   = false;
        bool stat_rx_ongoing      = false;
-       bool dcd                                  = false;
+       bool dcd                  = false;
        bool dcd_led              = false;
        bool dcd_waiting          = false;
+       long dcd_wait_until       = 0;
        uint16_t dcd_count        = 0;
-       uint16_t dcd_threshold    = 15;
+       uint16_t dcd_threshold    = 6;
 
        uint32_t status_interval_ms = STATUS_INTERVAL_MS;
        uint32_t last_status_update = 0;
@@ -396,7 +400,7 @@
     float battery_percent = 0.0;
     uint8_t battery_state = 0x00;
     uint8_t display_intensity = 0xFF;
-    bool display_diagnostics = true;
+    bool display_diagnostics = true;    
     bool device_init_done = false;
     bool eeprom_ok = false;
     bool firmware_update_mode = false;

diff --git a/Makefile b/Makefile
index 3108f4a5319284d3d70bbd99b687cc0ac2b057a6..fb7c5466719a4f4f1bab5303808725f50f191174 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -99,11 +99,11 @@ upload-mega2560:
        arduino-cli upload -p /dev/ttyACM0 --fqbn arduino:avr:mega
 
 upload-tbeam:
-       arduino-cli upload -p /dev/ttyUSB1 --fqbn esp32:esp32:t-beam
+       arduino-cli upload -p /dev/ttyACM0 --fqbn esp32:esp32:t-beam
        @sleep 1
-       rnodeconf /dev/ttyUSB1 --firmware-hash $$(./partition_hashes ./build/esp32.esp32.t-beam/RNode_Firmware.ino.bin)
+       rnodeconf /dev/ttyACM0 --firmware-hash $$(./partition_hashes ./build/esp32.esp32.t-beam/RNode_Firmware.ino.bin)
        @sleep 3
-       python ./Release/esptool/esptool.py --chip esp32 --port /dev/ttyUSB1 --baud 921600 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size 4MB 0x210000 ./Release/console_image.bin
+       python ./Release/esptool/esptool.py --chip esp32 --port /dev/ttyACM0 --baud 921600 --before default_reset --after hard_reset write_flash -z --flash_mode dio --flash_freq 80m --flash_size 4MB 0x210000 ./Release/console_image.bin
 
 upload-lora32_v10:
        arduino-cli upload -p /dev/ttyUSB0 --fqbn esp32:esp32:ttgo-lora32

diff --git a/RNode_Firmware.ino b/RNode_Firmware.ino
index ae34b725606a7d4ea733beeba44f2ebae917f169..0bf649a3f88df7e4cfd07b8653ad2a5a7167ba63 100644 (file)
--- a/RNode_Firmware.ino
+++ b/RNode_Firmware.ino
@@ -373,6 +373,7 @@ void flushQueue(void) {
   if (!queue_flushing) {
     queue_flushing = true;
 
+    led_tx_on();
     uint16_t processed = 0;
 
     #if MCU_VARIANT == MCU_ESP32
@@ -394,6 +395,9 @@ void flushQueue(void) {
         processed++;
       }
     }
+
+    lora_receive();
+    led_tx_off();
   }
 
   queue_height = 0;
@@ -439,6 +443,7 @@ void update_airtime() {
     }
     longterm_channel_util = (float)longterm_channel_util_sum/(float)AIRTIME_BINS;
 
+    update_csma_p();
     kiss_indicate_channel_stats();
   #endif
 }
@@ -446,7 +451,6 @@ void update_airtime() {
 void transmit(uint16_t size) {
   if (radio_online) {
     if (!promisc) {
-      led_tx_on();
       uint16_t  written = 0;
       uint8_t header  = random(256) & 0xF0;
 
@@ -471,9 +475,6 @@ void transmit(uint16_t size) {
       }
 
       LoRa.endPacket(); add_airtime(written);
-      led_tx_off();
-
-      lora_receive();
     } else {
       // In promiscuous mode, we only send out
       // plain raw LoRa packets with a maximum
@@ -500,9 +501,6 @@ void transmit(uint16_t size) {
         written++;
       }
       LoRa.endPacket(); add_airtime(written);
-      led_tx_off();
-
-      lora_receive();
     }
   } else {
     kiss_indicate_error(ERROR_TXFAILED);
@@ -934,7 +932,7 @@ void updateModemStatus() {
     }
   } else {
     if (dcd_count > 0) {
-      dcd_count--;
+      dcd_count = 0;
     } else {
       dcd_led = false;
     }
@@ -1099,6 +1097,13 @@ void validate_status() {
   }
 }
 
+#define _e 2.71828183
+#define _S 10.0
+float csma_slope(float u) { return (pow(_e,_S*u-_S/2.0))/(pow(_e,_S*u-_S/2.0)+1.0); }
+void update_csma_p() {
+  csma_p = (uint8_t)((1.0-(csma_p_min+(csma_p_max-csma_p_min)*csma_slope(airtime)))*255.0);
+}
+
 void loop() {
   if (radio_online) {
     checkModemStatus();
@@ -1121,21 +1126,41 @@ void loop() {
 
     if (!airtime_lock) {
       if (queue_height > 0) {
-        if (!dcd_waiting) updateModemStatus();
-
-        if (!dcd && !dcd_led) {
-          if (dcd_waiting) delay(lora_rx_turnaround_ms);
+        #if MCU_VARIANT == MCU_ESP32
 
-          updateModemStatus();
+          if (dcd_waiting && (millis() >= dcd_wait_until)) { dcd_waiting = false; }
+          if (!dcd_waiting) {
+            updateModemStatus();
+            long check_time = millis();
 
-          if (!dcd) {
-            dcd_waiting = false;
-            flushQueue();
+            if (!dcd) {
+              uint8_t csma_r = (uint8_t)random(256);
+              if (csma_p >= csma_r) {
+                flushQueue();
+              } else {
+                dcd_waiting = true;
+                dcd_wait_until = check_time+csma_slot_ms;
+              }
+            }
           }
+          
+        #else
+          if (!dcd_waiting) updateModemStatus();
 
-        } else {
-          dcd_waiting = true;
-        }
+          if (!dcd && !dcd_led) {
+            if (dcd_waiting) delay(lora_rx_turnaround_ms);
+
+            updateModemStatus();
+
+            if (!dcd) {
+              dcd_waiting = false;
+              flushQueue();
+            }
+
+          } else {
+            dcd_waiting = true;
+          }
+        #endif
       }
     }
   

diff --git a/Utilities.h b/Utilities.h
index db022580105a2b8d553c3907a605a31df47db6a3..3c7161897d0ececf27741db04c45604431b4dc8d 100644 (file)
--- a/Utilities.h
+++ b/Utilities.h
@@ -912,6 +912,7 @@ void updateBitrate() {
                        lora_symbol_time_ms = (1.0/lora_symbol_rate)*1000.0;
                        lora_bitrate = (uint32_t)(lora_sf * ( (4.0/(float)lora_cr) / ((float)(pow(2, lora_sf))/((float)lora_bw/1000.0)) ) * 1000.0);
                        lora_us_per_byte = 1000000.0/((float)lora_bitrate/8.0);
+                       csma_slot_ms = lora_symbol_time_ms*10;
                } else {
                        lora_bitrate = 0;
                }