Fixed issue in unconfirmed_retransmission behavior

Fixed issue on LoRaWANStack based on lorawan v1.0.2 specification page
24 line 25-27. The specification mentioned that that end-device shall
stop retransmission when receiving ANY downlink on RX1 or RX2 window.

- Removed conflicting behavior in
  LoRaWANStack::post_process_tx_with_reception()
- Updated comment section of nb_trials at lorawan_data_structures.h

Author: Zulkarnaen

connectivity/lorawan/source/LoRaWANStack.cpp

@@ -619,29 +619,12 @@ void LoRaWANStack::post_process_tx_with_reception()
             }
         }
     } else {
-        // handle UNCONFIRMED case here, RX slots were turned off due to
-        // valid packet reception.
-        uint8_t prev_QOS_level = _loramac.get_prev_QOS_level();
-        uint8_t QOS_level = _loramac.get_QOS_level();
-
-        // We will not apply QOS on the post-processing of the previous
-        // outgoing message as we would have received QOS instruction in response
-        // to that particular message
-        if (QOS_level > LORAWAN_DEFAULT_QOS && _qos_cnt < QOS_level
-                && (prev_QOS_level == QOS_level)) {
-            _ctrl_flags &= ~TX_DONE_FLAG;
-            const int ret = _queue->call(this, &LoRaWANStack::state_controller,
-                                         DEVICE_STATE_SCHEDULING);
-            MBED_ASSERT(ret != 0);
-            (void) ret;
-            _qos_cnt++;
-            tr_info("QOS: repeated transmission #%d queued", _qos_cnt);
-        } else {
-            _loramac.post_process_mcps_req();
-            _ctrl_flags |= TX_DONE_FLAG;
-            make_tx_metadata_available();
-            state_controller(DEVICE_STATE_STATUS_CHECK);
-        }
+        // On reception, end-device shall stop sending retransmission as stated in lorawan v1.0.2
+        // specification, page 24, line 25-27
+        _loramac.post_process_mcps_req();
+        _ctrl_flags |= TX_DONE_FLAG;
+        make_tx_metadata_available();
+        state_controller(DEVICE_STATE_STATUS_CHECK);
     }
 }
 

connectivity/lorawan/system/lorawan_data_structures.h

@@ -908,7 +908,7 @@ typedef struct {
      *
      * Provides a certain QOS level set by network server in LinkADRReq MAC
      * command. The device will transmit the given UNCONFIRMED message nb_trials
-     * time with same frame counter until a downlink is received. Standard defined
+     * time with the same frame counter OR until a downlink is received. Standard defined
      * range is 1:15. Data rates will NOT be adapted according to chapter 18.4.
      */
     uint8_t nb_trials;