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Commit 5ec063c9394e23bae96fe2133d3121326d3d226d
Parents : 08651f9
Author : Mark Qvist <mark@unsigned.io>
Date : 2025-01-07T20:15:26+01:00
Reworked CSMA algorithm
Changes
3 files changed, 146 insertions(+), 59 deletions(-)
Diff
diff --git a/Boards.h b/Boards.h
index aa1a4f1..6fb846d 100644
--- a/Boards.h
+++ b/Boards.h
@@ -19,6 +19,15 @@
#define PIN_DCD 5
#define PIN_TXSIG 4
+// #define PIN_DIFS 7
+// #define PIN_CW 6
+// #define PIN_FLUSH 5
+
+#define PIN_DIFS 3
+#define PIN_CW 3
+#define PIN_FLUSH 3
+///////////////////////////
+
#include "Modem.h"
#ifndef BOARDS_H
diff --git a/Config.h b/Config.h
index f6569b4..4993ccf 100644
--- a/Config.h
+++ b/Config.h
@@ -67,31 +67,41 @@
const int rssi_offset = 157;
// Default LoRa settings
- const int lora_rx_turnaround_ms = 66;
- const int lora_post_tx_yield_slots = 6;
- uint32_t post_tx_yield_timeout = 0;
#define PHY_HEADER_LORA_SYMBOLS 20
#define PHY_CRC_LORA_BITS 16
#define LORA_PREAMBLE_SYMBOLS_MIN 18
#define LORA_PREAMBLE_TARGET_MS 15
#define LORA_CAD_SYMBOLS 3
- #define CSMA_SLOT_SYMBOLS 12
+ long lora_preamble_symbols = 12;
+ long lora_preamble_time_ms = 0;
+ long lora_header_time_ms = 0;
+ float lora_symbol_time_ms = 0.0;
+ float lora_symbol_rate = 0.0;
+ float lora_us_per_byte = 0.0;
+ bool lora_low_datarate = false;
+
+ // CSMA Parameters
+ #define CSMA_POST_TX_YIELD_SLOTS 3
#define CSMA_SLOT_MAX_MS 100
#define CSMA_SLOT_MIN_MS 24
-
- long lora_preamble_symbols = 12;
- long lora_preamble_time_ms = 0;
- long lora_header_time_ms = 0;
- float lora_symbol_time_ms = 0.0;
- float lora_symbol_rate = 0.0;
- float lora_us_per_byte = 0.0;
- bool lora_low_datarate = false;
-
- int csma_slot_ms = 50;
+ #define CSMA_SLOT_SYMBOLS 12
+ #define CSMA_CW_MIN 0
+ #define CSMA_CW_MAX 15
+ #define CSMA_SIFS_MS 0
+ int csma_slot_ms = CSMA_SLOT_MIN_MS;
+ long difs_ms = CSMA_SIFS_MS + 2*csma_slot_ms; // Distributed interframe space
+ long difs_wait_start = -1;
+ long cw_wait_start = -1;
+ long cw_wait_target = -1;
+ long cw_wait_passed = 0;
+ int csma_cw = -1;
+
+ ////////////////////////////////////////
float csma_p_min = 0.15;
float csma_p_max = 0.333;
float csma_b_speed = 0.15;
uint8_t csma_p = 85;
+ ////////////////////////////////////////
int lora_sf = 0;
int lora_cr = 5;
diff --git a/RNode_Firmware.ino b/RNode_Firmware.ino
index f38162b..e6a85e8 100644
--- a/RNode_Firmware.ino
+++ b/RNode_Firmware.ino
@@ -64,6 +64,9 @@ void setup() {
pinMode(PIN_HEADER, OUTPUT);
pinMode(PIN_DCD, OUTPUT);
pinMode(PIN_TXSIG, OUTPUT);
+ pinMode(PIN_DIFS, OUTPUT);
+ pinMode(PIN_CW, OUTPUT);
+ pinMode(PIN_FLUSH, OUTPUT);
///////////////////////////
#if MCU_VARIANT == MCU_ESP32
@@ -521,7 +524,7 @@ bool queueFull() {
}
volatile bool queue_flushing = false;
-void flushQueue(void) {
+void flush_queue(void) {
if (!queue_flushing) {
// TODO: Remove debug
@@ -554,7 +557,6 @@ void flushQueue(void) {
lora_receive();
led_tx_off();
- post_tx_yield_timeout = millis()+(lora_post_tx_yield_slots*csma_slot_ms);
}
queue_height = 0;
@@ -628,7 +630,7 @@ void update_airtime() {
longterm_channel_util = (float)longterm_channel_util_sum/(float)AIRTIME_BINS;
#if MCU_VARIANT == MCU_ESP32 || MCU_VARIANT == MCU_NRF52
- update_csma_p();
+ update_csma_parameters();
#endif
kiss_indicate_channel_stats();
#endif
@@ -1199,7 +1201,9 @@ void serialCallback(uint8_t sbyte) {
portMUX_TYPE update_lock = portMUX_INITIALIZER_UNLOCKED;
#endif
-void updateModemStatus() {
+bool medium_free() { update_modem_status(); return !dcd; }
+
+void update_modem_status() {
#if MCU_VARIANT == MCU_ESP32
portENTER_CRITICAL(&update_lock);
#elif MCU_VARIANT == MCU_NRF52
@@ -1225,9 +1229,9 @@ void updateModemStatus() {
else { led_rx_off(); } }
}
-void checkModemStatus() {
+void check_modem_status() {
if (millis()-last_status_update >= status_interval_ms) {
- updateModemStatus();
+ update_modem_status();
#if MCU_VARIANT == MCU_ESP32 || MCU_VARIANT == MCU_NRF52
util_samples[dcd_sample] = dcd;
@@ -1385,13 +1389,56 @@ void validate_status() {
#define _e 2.71828183
#define _S 12.5
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() {
+ void update_csma_parameters() {
csma_p = (uint8_t)((1.0-(csma_p_min+(csma_p_max-csma_p_min)*csma_slope(airtime+csma_b_speed)))*255.0);
}
#endif
+void tx_queue_handler() {
+ if (!airtime_lock && queue_height > 0) {
+ if (csma_cw == -1) {
+ csma_cw = random(CSMA_CW_MIN, CSMA_CW_MAX);
+ cw_wait_target = csma_cw * csma_slot_ms;
+ }
+
+ // TODO: Remove metering signallers
+ if (difs_wait_start == -1) { digitalWrite(PIN_DIFS, LOW); }
+ if (cw_wait_start == -1) { digitalWrite(PIN_CW, LOW); } else { digitalWrite(PIN_CW, HIGH); }
+ ////////////////////////////////
+
+ if (difs_wait_start == -1) { // DIFS wait not yet started
+ if (medium_free()) { difs_wait_start = millis(); digitalWrite(PIN_DIFS, HIGH); return; } // Set DIFS wait start time
+ else { return; } } // Medium not yet free, continue waiting
+
+ else { // We are waiting for DIFS or CW to pass
+ if (!medium_free()) { difs_wait_start = -1; cw_wait_start = -1; return; } // Medium became occupied while in DIFS wait, restart waiting when free again
+ else { // Medium is free, so continue waiting
+ if (millis() < difs_wait_start+difs_ms) { return; } // DIFS has not yet passed, continue waiting
+ else { // DIFS has passed, and we are now in CW wait
+ digitalWrite(PIN_DIFS, LOW);
+ if (cw_wait_start == -1) { cw_wait_start = millis(); digitalWrite(PIN_CW, HIGH); return; } // If we haven't started counting CW wait time, do it from now
+ else { // If we are already counting CW wait time, add it to the counter
+ cw_wait_passed += millis()-cw_wait_start; cw_wait_start = millis();
+ if (cw_wait_passed < cw_wait_target) { return; } // Contention window wait time has not yet passed, continue waiting
+ else { // Wait time has passed, flush the queue
+ digitalWrite(PIN_FLUSH, HIGH);
+ digitalWrite(PIN_CW, LOW);
+ flush_queue();
+ digitalWrite(PIN_FLUSH, LOW);
+ digitalWrite(PIN_DIFS, LOW);
+ cw_wait_passed = 0; csma_cw = -1; difs_wait_start = -1; }
+
+ }
+ }
+ }
+ }
+ }
+}
+
void loop() {
if (radio_online) {
+ update_modem_status(); // TODO: Remove debug
+
#if MCU_VARIANT == MCU_ESP32
modem_packet_t *modem_packet = NULL;
if(modem_packet_queue && xQueueReceive(modem_packet_queue, &modem_packet, 0) == pdTRUE && modem_packet) {
@@ -1434,50 +1481,57 @@ void loop() {
#endif
- checkModemStatus();
- if (!airtime_lock) {
- if (queue_height > 0) {
- #if MCU_VARIANT == MCU_ESP32 || MCU_VARIANT == MCU_NRF52
-
- long check_time = millis();
- if (check_time > post_tx_yield_timeout) {
- if (dcd_waiting && (check_time >= dcd_wait_until)) { dcd_waiting = false; }
- if (!dcd_waiting) {
- for (uint8_t dcd_i = 0; dcd_i < dcd_threshold*2; dcd_i++) {
- delay(STATUS_INTERVAL_MS); updateModemStatus();
- }
+ update_modem_status(); // TODO: Remove debug
- if (!dcd) {
- uint8_t csma_r = (uint8_t)random(256);
- if (csma_p >= csma_r) {
- flushQueue();
- } else {
- dcd_waiting = true;
- dcd_wait_until = millis()+csma_slot_ms;
- }
- }
- }
- }
+ tx_queue_handler();
+
+ update_modem_status(); // TODO: Remove debug
+
+ check_modem_status();
+
+ update_modem_status(); // TODO: Remove debug
+
+ // if (queue_height > 0) {
+ // #if MCU_VARIANT == MCU_ESP32 || MCU_VARIANT == MCU_NRF52
+
+ // long check_time = millis();
+ // if (check_time > post_tx_yield_timeout) {
+ // if (dcd_waiting && (check_time >= dcd_wait_until)) { dcd_waiting = false; }
+ // if (!dcd_waiting) {
+ // for (uint8_t dcd_i = 0; dcd_i < dcd_threshold*2; dcd_i++) {
+ // delay(STATUS_INTERVAL_MS); updateModemStatus();
+ // }
+
+ // if (!dcd) {
+ // uint8_t csma_r = (uint8_t)random(256);
+ // if (csma_p >= csma_r) {
+ // flushQueue();
+ // } else {
+ // dcd_waiting = true;
+ // dcd_wait_until = millis()+csma_slot_ms;
+ // }
+ // }
+ // }
+ // }
- #else
- if (!dcd_waiting) updateModemStatus();
+ // #else
+ // if (!dcd_waiting) updateModemStatus();
- if (!dcd) {
- if (dcd_waiting) delay(lora_rx_turnaround_ms);
+ // if (!dcd) {
+ // if (dcd_waiting) delay(lora_rx_turnaround_ms);
- updateModemStatus();
+ // updateModemStatus();
- if (!dcd) {
- dcd_waiting = false;
- flushQueue();
- }
+ // if (!dcd) {
+ // dcd_waiting = false;
+ // flushQueue();
+ // }
- } else {
- dcd_waiting = true;
- }
- #endif
- }
- }
+ // } else {
+ // dcd_waiting = true;
+ // }
+ // #endif
+ // }
} else {
if (hw_ready) {
@@ -1497,27 +1551,41 @@ void loop() {
#if MCU_VARIANT == MCU_ESP32 || MCU_VARIANT == MCU_NRF52
buffer_serial();
+ update_modem_status(); // TODO: Remove debug
+
if (!fifo_isempty(&serialFIFO)) serial_poll();
+
+ update_modem_status(); // TODO: Remove debug
#else
if (!fifo_isempty_locked(&serialFIFO)) serial_poll();
#endif
+ update_modem_status(); // TODO: Remove debug
+
#if HAS_DISPLAY
if (disp_ready) update_display();
#endif
+ update_modem_status(); // TODO: Remove debug
+
#if HAS_PMU
if (pmu_ready) update_pmu();
#endif
+ update_modem_status(); // TODO: Remove debug
+
#if HAS_BLUETOOTH || HAS_BLE == true
if (!console_active && bt_ready) update_bt();
#endif
+ update_modem_status(); // TODO: Remove debug
+
#if HAS_INPUT
input_read();
#endif
+ update_modem_status(); // TODO: Remove debug
+
if (memory_low) {
#if PLATFORM == PLATFORM_ESP32
if (esp_get_free_heap_size() < 8192) {
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