LoRaWAN: Reduced priority for automatic uplinks & higher data rate usage for connection establishment

features/lorawan/LoRaWANStack.cpp

@@ -603,17 +603,14 @@ void LoRaWANStack::process_transmission(void)
             _ctrl_flags &= ~TX_DONE_FLAG;
             tr_debug("Awaiting ACK");
             _device_current_state = DEVICE_STATE_AWAITING_ACK;
-            return;
-        }
-
-        // Class A unconfirmed message sent, TX_DONE event will be sent to
-        // application when RX2 windows is elapsed, i.e., in process_reception_timeout()
-        _ctrl_flags &= ~TX_ONGOING_FLAG;
-        _ctrl_flags |= TX_DONE_FLAG;
-
-        // In Class C, reception timeout never happens, so we handle the state
-        // progression for TX_DONE in UNCONFIRMED case here
-        if (_loramac.get_device_class() == CLASS_C) {
+        } else if (_loramac.get_device_class() == CLASS_A) {
+            // Class A unconfirmed message sent, TX_DONE event will be sent to
+            // application when RX2 windows is elapsed, i.e., in process_reception_timeout()
+            _ctrl_flags &= ~TX_ONGOING_FLAG;
+            _ctrl_flags |= TX_DONE_FLAG;
+        } else if (_loramac.get_device_class() == CLASS_C) {
+            // In Class C, reception timeout never happens, so we handle the state
+             // progression for TX_DONE in UNCONFIRMED case here
             _loramac.post_process_mcps_req();
             state_controller(DEVICE_STATE_STATUS_CHECK);
             state_machine_run_to_completion();
@@ -669,9 +666,10 @@ void LoRaWANStack::process_reception(const uint8_t *const payload, uint16_t size
                 state_controller(DEVICE_STATE_STATUS_CHECK);
             }
         }
-    } else {
+    } else if (_loramac.get_device_class() == CLASS_A) {
         // handle UNCONFIRMED case here, RX slots were turned off due to
-        // valid packet reception
+        // valid packet reception. For Class C, an outgoing UNCONFIRMED message
+        // gets its handling in process_transmission.
         _loramac.post_process_mcps_req();
         _ctrl_flags |= TX_DONE_FLAG;
         state_controller(DEVICE_STATE_STATUS_CHECK);
@@ -805,8 +803,12 @@ void LoRaWANStack::send_event_to_application(const lorawan_event_t event) const
 
 void LoRaWANStack::send_automatic_uplink_message(const uint8_t port)
 {
+    // we will silently ignore the automatic uplink event if the user is already
+    // sending something
     const int16_t ret = handle_tx(port, NULL, 0, MSG_CONFIRMED_FLAG, true, true);
-    if (ret < 0) {
+    if (ret == LORAWAN_STATUS_WOULD_BLOCK) {
+        _automatic_uplink_ongoing = false;
+    } else if (ret < 0) {
         tr_debug("Failed to generate AUTOMATIC UPLINK, error code = %d", ret);
         send_event_to_application(AUTOMATIC_UPLINK_ERROR);
     }

features/lorawan/lorastack/mac/LoRaMac.cpp

@@ -170,6 +170,8 @@ void LoRaMac::post_process_mcps_req()
             if (_params.is_ul_frame_counter_fixed == false) {
                 _params.ul_frame_counter++;
             }
+        } else {
+            _mcps_confirmation.status = LORAMAC_EVENT_INFO_STATUS_ERROR;
         }
     } else {
         //UNCONFIRMED or PROPRIETARY
@@ -671,7 +673,7 @@ void LoRaMac::on_radio_rx_done(const uint8_t *const payload, uint16_t size,
 {
     if (_device_class == CLASS_C && !_continuous_rx2_window_open) {
         open_rx2_window();
-    } else {
+    } else if (_device_class != CLASS_C){
         _lora_time.stop(_params.timers.rx_window1_timer);
         _lora_phy->put_radio_to_sleep();
     }
@@ -1078,13 +1080,13 @@ lorawan_status_t LoRaMac::schedule_tx()
     uint8_t dr_offset = _lora_phy->apply_DR_offset(_params.sys_params.channel_data_rate,
                                                   _params.sys_params.rx1_dr_offset);
 
-    _lora_phy->compute_rx_win_params(dr_offset, _params.sys_params.min_rx_symb,
-                                    _params.sys_params.max_sys_rx_error,
+    _lora_phy->compute_rx_win_params(dr_offset, MBED_CONF_LORA_DOWNLINK_PREAMBLE_LENGTH,
+                                    MBED_CONF_LORA_MAX_SYS_RX_ERROR,
                                     &_params.rx_window1_config);
 
     _lora_phy->compute_rx_win_params(_params.sys_params.rx2_channel.datarate,
-                                    _params.sys_params.min_rx_symb,
-                                    _params.sys_params.max_sys_rx_error,
+                                    MBED_CONF_LORA_DOWNLINK_PREAMBLE_LENGTH,
+                                    MBED_CONF_LORA_MAX_SYS_RX_ERROR,
                                     &_params.rx_window2_config);
 
     if (!_is_nwk_joined) {
@@ -1353,8 +1355,8 @@ void LoRaMac::set_device_class(const device_class_t &device_class,
         _params.is_node_ack_requested = false;
         _lora_phy->put_radio_to_sleep();
         _lora_phy->compute_rx_win_params(_params.sys_params.rx2_channel.datarate,
-                                        _params.sys_params.min_rx_symb,
-                                        _params.sys_params.max_sys_rx_error,
+                                        MBED_CONF_LORA_DOWNLINK_PREAMBLE_LENGTH,
+                                        MBED_CONF_LORA_MAX_SYS_RX_ERROR,
                                         &_params.rx_window2_config);
     }
 
@@ -1730,9 +1732,6 @@ lorawan_status_t LoRaMac::initialize(EventQueue *queue)
     _params.timers.aggregated_timeoff = 0;
 
     _lora_phy->reset_to_default_values(&_params, true);
-
-    _params.sys_params.max_sys_rx_error = 10;
-    _params.sys_params.min_rx_symb = 6;
     _params.sys_params.retry_num = 1;
 
     reset_mac_parameters();
@@ -1755,9 +1754,7 @@ lorawan_status_t LoRaMac::initialize(EventQueue *queue)
     _params.timers.mac_init_time = _lora_time.get_current_time();
 
     _params.sys_params.adr_on = MBED_CONF_LORA_ADR_ON;
-
-    _params.is_nwk_public = MBED_CONF_LORA_PUBLIC_NETWORK;
-    _lora_phy->setup_public_network_mode(MBED_CONF_LORA_PUBLIC_NETWORK);
+    _params.sys_params.channel_data_rate = _lora_phy->get_default_max_tx_datarate();
 
     return LORAWAN_STATUS_OK;
 }

features/lorawan/lorastack/phy/LoRaPHY.cpp

@@ -514,13 +514,16 @@ void LoRaPHY::reset_to_default_values(loramac_protocol_params *params, bool init
 
     params->sys_params.channel_tx_power = get_default_tx_power();
 
-    params->sys_params.channel_data_rate = get_default_tx_datarate();
+    // We shall always start with highest achievable data rate.
+    // Subsequent decrease in data rate will mean increase in range henceforth.
+    params->sys_params.channel_data_rate = get_default_max_tx_datarate();
 
     params->sys_params.rx1_dr_offset = phy_params.default_rx1_dr_offset;
 
     params->sys_params.rx2_channel.frequency = get_default_rx2_frequency();
 
-    params->sys_params.rx2_channel.datarate = get_default_rx2_datarate();
+    // RX2 data rate should also start from the maximum
+    params->sys_params.rx2_channel.datarate = get_default_max_tx_datarate();
 
     params->sys_params.uplink_dwell_time = phy_params.ul_dwell_time_setting;
 
@@ -560,6 +563,11 @@ uint8_t LoRaPHY::get_default_tx_datarate()
     return phy_params.default_datarate;
 }
 
+uint8_t  LoRaPHY::get_default_max_tx_datarate()
+{
+    return phy_params.default_max_datarate;
+}
+
 uint8_t LoRaPHY::get_default_tx_power()
 {
     return phy_params.default_tx_power;
@@ -845,7 +853,8 @@ bool LoRaPHY::rx_config(rx_config_params_t *rx_conf)
                               false, rx_conf->is_rx_continuous);
     } else {
         modem = MODEM_LORA;
-        _radio->set_rx_config(modem, rx_conf->bandwidth, phy_dr, 1, 0, 8,
+        _radio->set_rx_config(modem, rx_conf->bandwidth, phy_dr, 1, 0,
+                              MBED_CONF_LORA_DOWNLINK_PREAMBLE_LENGTH,
                               rx_conf->window_timeout, false, 0, false, 0, 0,
                               true, rx_conf->is_rx_continuous);
     }
@@ -895,7 +904,8 @@ bool LoRaPHY::tx_config(tx_config_params_t *tx_conf, int8_t *tx_power,
                               3000);
     } else {
         modem = MODEM_LORA;
-        _radio->set_tx_config(modem, phy_tx_power, 0, bandwidth, phy_dr, 1, 8,
+        _radio->set_tx_config(modem, phy_tx_power, 0, bandwidth, phy_dr, 1,
+                              MBED_CONF_LORA_UPLINK_PREAMBLE_LENGTH,
                               false, true, 0, 0, false, 3000);
     }
 

features/lorawan/lorastack/phy/LoRaPHY.h

@@ -423,6 +423,14 @@ class LoRaPHY : private mbed::NonCopyable<LoRaPHY> {
      */
     uint8_t get_default_tx_datarate();
 
+    /**
+     * @brief get_default_max_tx_datarate Gets the maximum achievable data rate for
+     *        LoRa modulation. This will always be the highest data rate achievable with
+     *        LoRa as defined in the regional specifications.
+     * @return Maximum achievable data rate with LoRa modulation.
+     */
+    uint8_t get_default_max_tx_datarate();
+
     /**
      * @brief get_default_tx_power Gets the default TX power
      * @return Default TX power

features/lorawan/lorastack/phy/LoRaPHYAS923.cpp

@@ -67,7 +67,7 @@
  */
 #define AS923_DEFAULT_DATARATE                      DR_2
 
-#define AS923_DEFAULT_MAX_DATARATE                  DR_7
+#define AS923_DEFAULT_MAX_DATARATE                  DR_5
 
 /*!
  * The minimum datarate which is used when the

features/lorawan/mbed_lib.json

@@ -64,6 +64,18 @@
         "automatic-uplink-message": {
             "help": "Stack will automatically send an uplink message when lora server requires immediate response",
             "value": true
+        },
+        "max-sys-rx-error": {
+        	"help": "Maximum timing error of the receiver in ms. The receiver will turn on in [-RxError : + RxError]",
+        	"value": 10
+        },
+        "downlink-preamble-length": {
+        	"help": "Number of preamble symbols need to be captured (out of 8) for successful demodulation",
+        	"value": 5
+        },
+        "uplink-preamble-length": {
+        	"help": "Number of preamble symbols to transmit. Must be <= 8",
+        	"value": 8
         }
     }
 }

features/lorawan/system/lorawan_data_structures.h

@@ -166,17 +166,6 @@ typedef struct {
      * The data rate in channels.
      */
     int8_t channel_data_rate;
-    /*!
-     * The system overall timing error in milliseconds.
-     * [-SystemMaxRxError : +SystemMaxRxError]
-     * Default: +/-10 ms
-     */
-    uint32_t max_sys_rx_error;
-    /*!
-     * The minimum number of symbols required to detect an RX frame.
-     * Default: 6 symbols
-     */
-    uint8_t min_rx_symb;
     /*!
      * LoRaMac maximum time a reception window stays open.
      */