Application example using LoRaWAN-lib MAC layer implementation

Dependencies:   mbed LoRaWAN-lib SX1276Lib

Dependents:   LoRaWAN-mbed-client-ttn0

LoRaWAN-demo is a ClassA device example project using LoRaWAN-lib and SX1276Lib libraries.

This demo application sends a frame every 4 to 6 seconds (randomly) and displays its current status using a serial port as display(VT100).

The serial port settings are as shown in below image. To access the serial port settings please click on "Setup" menu and then "Serial port..."

/media/uploads/mluis/serial_port_settings.png

The terminal window should be setup as shown in below image. To access the terminal window settings please click on "Setup" menu and then "Terminal..."

/media/uploads/mluis/terminal_window_settings.png

The image below shows the VT100 application status.

Application main screen

The application gives the possibility to either activate the device using

  • Over The Air Activation (OTAA)
  • Personalization activation (PA)

The activation mode can be adjusted in Comissioning.h by changing the following parameter:

/*!
 * When set to 1 the application uses the Over-the-Air activation procedure
 * When set to 0 the application uses the Personalization activation procedure
 */
#define OVER_THE_AIR_ACTIVATION                     1


The application gives the possibility to select which kind of network we are connecting to.

  • Public Network (true)
  • Private Network (false)

The netork type can be changed as follows:

/*!
 * Indicates if the end-device is to be connected to a private or public network
 */
#define LORAWAN_PUBLIC_NETWORK                      true


OTAA
When OTAA is selected the user must porvide a device EUI, an application EUI and an application key.
These can be adjusted by changing the following parameters:

/*!
 * Mote device IEEE EUI (big endian)
 */
#define LORAWAN_DEVICE_EUI                          { 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88 }

/*!
 * Application IEEE EUI (big endian)
 */
#define LORAWAN_APPLICATION_EUI                     { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }

/*!
 * AES encryption/decryption cipher application key
 */
#define LORAWAN_APPLICATION_KEY                     { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C }


PA
When PA is selected the user must porvide a network ID, a device address, a network session key and an application session key.
These can be adjusted by changing the following parameters:

/*!
 * Current network ID
 */
#define LORAWAN_NETWORK_ID                          ( uint32_t )0

/*!
 * Device address on the network (big endian)
 */
#define LORAWAN_DEVICE_ADDRESS                      ( uint32_t )0x12345678

/*!
 * AES encryption/decryption cipher network session key
 */
#define LORAWAN_NWKSKEY                             { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C }

/*!
 * AES encryption/decryption cipher application session key
 */
#define LORAWAN_APPSKEY                             { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C }


On top of main.c the user has the possibility to tweak some application settings such as:

  • Join requests transmission frequency
  • Frames transmission frequency
  • Application default datarate
  • Confirmed or Unconfirmed frames transmission
  • ADR (Adaptive Datarate) ON/OFF
  • Application port to be used by the transmitted frames

The join requests transmission frequency can be adjusted by changing the follwoing parameter:

/*!
 * Join requests trials duty cycle.
 */
#define OVER_THE_AIR_ACTIVATION_DUTYCYCLE           10000000  // 10 [s] value in us


The frame transmission frequency can be adjusted by changing the follwoing parameters:

/*!
 * Defines the application data transmission duty cycle. 5s, value in [us].
 */
#define APP_TX_DUTYCYCLE                            5000000

/*!
 * Defines a random delay for application data transmission duty cycle. 1s,
 * value in [us].
 */
#define APP_TX_DUTYCYCLE_RND                        1000000


The frame transmission scheduling is then executed as follows:

        if( ScheduleNextTx == true )
        {
            ScheduleNextTx = false;
            // Schedule next packet transmission
            TxDutyCycleTime = APP_TX_DUTYCYCLE + randr( -APP_TX_DUTYCYCLE_RND, APP_TX_DUTYCYCLE_RND );
            TimerSetValue( &TxNextPacketTimer, TxDutyCycleTime );
            TimerStart( &TxNextPacketTimer );
        }


The application default datarate can be adjusted by changing the following parameter:

Quote:

When ADR is off this setting is the fixed datarate that will be used by the application.
When ADR is on this setting is the initial datarate used by the application.

/*!
 * Default mote datarate
 */
#define LORAWAN_DEFAULT_DATARATE                    DR_0


The transmitted frame contents will depend on LORAWAN_CONFIRMED_MSG_ON value.

/*!
 * LoRaWAN confirmed messages
 */
#define LORAWAN_CONFIRMED_MSG_ON                    true
  • If LORAWAN_CONFIRMED_MSG_ON equals false then the application payload is one byte corresponding to the AppLed state.
  • If LORAWAN_CONFIRMED_MSG_ON equals true then the application payload is six bytes corresponding to the AppLed state, Downlink counter (unsigned 16 bits), received RSSI (signed 16 bits) and received SNR (signed 8 bits).

/*!
 * \brief   Prepares the payload of the frame
 */
static void PrepareTxFrame( uint8_t port )
{

    switch( port )
    {
    case 15:
        {
            AppData[0] = AppLedStateOn;
            if( IsTxConfirmed == true )
            {
                AppData[1] = LoRaMacDownlinkStatus.DownlinkCounter >> 8;
                AppData[2] = LoRaMacDownlinkStatus.DownlinkCounter;
                AppData[3] = LoRaMacDownlinkStatus.Rssi >> 8;
                AppData[4] = LoRaMacDownlinkStatus.Rssi;
                AppData[5] = LoRaMacDownlinkStatus.Snr;
            }
        }
        break;
    case 224:
...
}


The ADR enabling/disabling can be adjusted by changing the following parameter:

/*!
 * LoRaWAN Adaptive Data Rate
 *
 * \remark Please note that when ADR is enabled the end-device should be static
 */
#define LORAWAN_ADR_ON                              1


The application port can be adjusted by changing the following parameter:

/*!
 * LoRaWAN application port
 */
#define LORAWAN_APP_PORT                            15
Revision:
0:92bca02df485
Child:
1:352f608c3337
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/main.cpp	Tue Oct 20 13:23:35 2015 +0000
@@ -0,0 +1,551 @@
+/*
+ / _____)             _              | |
+( (____  _____ ____ _| |_ _____  ____| |__
+ \____ \| ___ |    (_   _) ___ |/ ___)  _ \
+ _____) ) ____| | | || |_| ____( (___| | | |
+(______/|_____)_|_|_| \__)_____)\____)_| |_|
+    (C)2015 Semtech
+
+Description: LoRaMac classA device implementation
+
+License: Revised BSD License, see LICENSE.TXT file include in the project
+
+Maintainer: Miguel Luis and Gregory Cristian
+*/
+#include "mbed.h"
+#include "board.h"
+#include "radio.h"
+
+#include "LoRaMac.h"
+
+#include "SerialDisplay.h"
+
+/*!
+ * When set to 1 the application uses the Over-the-Air activation procedure
+ * When set to 0 the application uses the Personalization activation procedure
+ */
+#define OVER_THE_AIR_ACTIVATION                     1
+
+/*!
+ * Indicates if the end-device is to be connected to a private or public network
+ */
+#define LORAWAN_PUBLIC_NETWORK                      true
+
+#if( OVER_THE_AIR_ACTIVATION != 0 )
+
+/*!
+ * Join requests trials duty cycle.
+ */
+#define OVER_THE_AIR_ACTIVATION_DUTYCYCLE           10000000  // 10 [s] value in us
+
+/*!
+ * Mote device IEEE EUI
+ *
+ * \remark must be written as a little endian value (reverse order of normal reading)
+ */
+#define LORAWAN_DEVICE_EUI                          { 0x88, 0x77, 0x66, 0x55, 0x44, 0x33, 0x22, 0x11 }
+
+/*!
+ * Application IEEE EUI
+ *
+ * \remark must be written as a little endian value (reverse order of normal reading)
+ */
+#define LORAWAN_APPLICATION_EUI                     { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 }
+
+/*!
+ * AES encryption/decryption cipher application key
+ */
+#define LORAWAN_APPLICATION_KEY                     { 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF, 0x00 }
+
+#else
+
+/*!
+ * Current network ID
+ */
+#define LORAWAN_NETWORK_ID                          ( uint32_t )0
+
+/*!
+ * Device address on the network
+ *
+ * \remark must be written as a big endian value (normal reading order)
+ */
+#define LORAWAN_DEVICE_ADDRESS                      ( uint32_t )0x12345678
+
+/*!
+ * AES encryption/decryption cipher network session key
+ */
+#define LORAWAN_NWKSKEY                             { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C }
+
+/*!
+ * AES encryption/decryption cipher application session key
+ */
+#define LORAWAN_APPSKEY                             { 0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C }
+
+#endif
+
+/*!
+ * Defines the application data transmission duty cycle
+ */
+#define APP_TX_DUTYCYCLE                            5000000  // 5 [s] value in us
+#define APP_TX_DUTYCYCLE_RND                        1000000  // 1 [s] value in us
+
+/*!
+ * LoRaWAN confirmed messages
+ */
+#define LORAWAN_CONFIRMED_MSG_ON                    true
+
+/*!
+ * LoRaWAN Adaptative Data Rate
+ *
+ * \remark Please note that when ADR is enabled the end-device should be static
+ */
+#define LORAWAN_ADR_ON                              1
+
+/*!
+ * LoRaWAN ETSI duty cycle control enable/disable
+ *
+ * \remark Please note that ETSI mandates duty cycled transmissions. Use only for test purposes
+ */
+#define LORAWAN_DUTYCYCLE_ON                        false
+
+/*!
+ * LoRaWAN application port
+ */
+#define LORAWAN_APP_PORT                            15
+
+/*!
+ * User application data buffer size
+ */
+#if ( LORAWAN_CONFIRMED_MSG_ON == 1 )
+#define LORAWAN_APP_DATA_SIZE                       6
+
+#else
+#define LORAWAN_APP_DATA_SIZE                       1
+
+#endif
+
+#if( OVER_THE_AIR_ACTIVATION != 0 )
+
+static uint8_t DevEui[] = LORAWAN_DEVICE_EUI;
+static uint8_t AppEui[] = LORAWAN_APPLICATION_EUI;
+static uint8_t AppKey[] = LORAWAN_APPLICATION_KEY;
+
+#else
+
+static uint8_t NwkSKey[] = LORAWAN_NWKSKEY;
+static uint8_t AppSKey[] = LORAWAN_APPSKEY;
+
+#endif
+
+/*!
+ * Indicates if the MAC layer has already joined a network.
+ */
+static bool IsNetworkJoined = false;
+static bool IsNetworkJoinedStatusUpdate = false;
+
+/*!
+ * User application data
+ */
+static uint8_t AppData[LORAWAN_APP_DATA_SIZE];
+
+/*!
+ * Defines the application data transmission duty cycle
+ */
+static uint32_t TxDutyCycleTime;
+
+TimerEvent_t TxNextPacketTimer;
+
+#if( OVER_THE_AIR_ACTIVATION != 0 )
+
+/*!
+ * Defines the join request timer
+ */
+TimerEvent_t JoinReqTimer;
+
+#endif
+
+/*!
+ * Indicates if a new packet can be sent
+ */
+static bool TxNextPacket = true;
+static bool ScheduleNextTx = false;
+
+static bool AppLedStateOn = false;
+
+static LoRaMacEvent_t LoRaMacEvents;
+
+TimerEvent_t Led1Timer;
+volatile bool Led1StateChanged = false;
+
+TimerEvent_t Led2Timer;
+volatile bool Led2StateChanged = false;
+
+volatile bool Led3StateChanged = false;
+
+volatile bool LinkStatusUpdated = false;
+
+struct sLoRaMacUplinkStatus
+{
+    uint8_t Acked;
+    int8_t Datarate;
+    uint16_t UplinkCounter;
+    uint8_t Port;
+    uint8_t *Buffer;
+    uint8_t BufferSize;
+}LoRaMacUplinkStatus;
+
+struct sLoRaMacDownlinkStatus
+{
+    int16_t Rssi;
+    int8_t Snr;
+    uint16_t DownlinkCounter;
+    bool RxData;
+    uint8_t Port;
+    uint8_t *Buffer;
+    uint8_t BufferSize;
+}LoRaMacDownlinkStatus;
+
+void SerialDisplayRefresh( void )
+{
+    SerialDisplayInit( );
+    SerialDisplayUpdateActivationMode( OVER_THE_AIR_ACTIVATION );
+
+#if( OVER_THE_AIR_ACTIVATION == 0 )
+    SerialDisplayUpdateNwkId( LORAWAN_NETWORK_ID );
+    SerialDisplayUpdateDevAddr( LORAWAN_DEVICE_ADDRESS );
+    SerialDisplayUpdateKey( 12, NwkSKey );
+    SerialDisplayUpdateKey( 13, AppSKey );
+#else
+    SerialDisplayUpdateEui( 5, DevEui );
+    SerialDisplayUpdateEui( 6, AppEui );
+    SerialDisplayUpdateKey( 7, AppKey );
+#endif
+    SerialDisplayUpdateNetworkIsJoined( IsNetworkJoined );
+
+    SerialDisplayUpdateAdr( LORAWAN_ADR_ON );
+    SerialDisplayUpdateDutyCycle( LORAWAN_DUTYCYCLE_ON );
+    SerialDisplayUpdatePublicNetwork( LORAWAN_PUBLIC_NETWORK );
+    
+    SerialDisplayUpdateLedState( 3, AppLedStateOn );
+}
+
+void SerialRxProcess( void )
+{
+    if( SerialDisplayReadable( ) == true )
+    {
+        switch( SerialDisplayGetChar( ) )
+        {
+            case 'R':
+            case 'r':
+                // Refresh Serial screen
+                SerialDisplayRefresh( );
+                break;
+            default:
+                break;
+        }
+    }
+}
+
+/*!
+ * Prepares the frame buffer to be sent
+ */
+static void PrepareTxFrame( uint8_t port )
+{
+    AppData[0] = AppLedStateOn;
+#if ( LORAWAN_CONFIRMED_MSG_ON == true )
+    AppData[1] = LoRaMacDownlinkStatus.DownlinkCounter >> 8;
+    AppData[2] = LoRaMacDownlinkStatus.DownlinkCounter;
+    AppData[3] = LoRaMacDownlinkStatus.Rssi >> 8;
+    AppData[4] = LoRaMacDownlinkStatus.Rssi;
+    AppData[5] = LoRaMacDownlinkStatus.Snr;
+#endif
+}
+
+static void ProcessRxFrame( LoRaMacEventFlags_t *flags, LoRaMacEventInfo_t *info )
+{
+    switch( info->RxPort ) // Check Rx port number
+    {
+        case 1: // The application LED can be controlled on port 1 or 2
+        case 2:
+            if( info->RxBufferSize == 1 )
+            {
+                AppLedStateOn = info->RxBuffer[0] & 0x01;
+                Led3StateChanged = true;
+            }
+            break;
+        default:
+            break;
+    }
+}
+
+static bool SendFrame( void )
+{
+    uint8_t sendFrameStatus = 0;
+
+    LoRaMacUplinkStatus.Acked = false;
+    LoRaMacUplinkStatus.Port = LORAWAN_APP_PORT;
+    LoRaMacUplinkStatus.Buffer = AppData;
+    LoRaMacUplinkStatus.BufferSize = LORAWAN_APP_DATA_SIZE;
+    
+    SerialDisplayUpdateFrameType( LORAWAN_CONFIRMED_MSG_ON );
+#if( LORAWAN_CONFIRMED_MSG_ON == false )
+    sendFrameStatus = LoRaMacSendFrame( LORAWAN_APP_PORT, AppData, LORAWAN_APP_DATA_SIZE );
+#else
+    sendFrameStatus = LoRaMacSendConfirmedFrame( LORAWAN_APP_PORT, AppData, LORAWAN_APP_DATA_SIZE, 8 );
+#endif
+    switch( sendFrameStatus )
+    {
+    case 5: // NO_FREE_CHANNEL
+        // Try again later
+        return true;
+    default:
+        return false;
+    }
+}
+
+#if( OVER_THE_AIR_ACTIVATION != 0 )
+
+/*!
+ * \brief Function executed on JoinReq Timeout event
+ */
+static void OnJoinReqTimerEvent( void )
+{
+    TimerStop( &JoinReqTimer );
+    TxNextPacket = true;
+}
+
+#endif
+
+/*!
+ * \brief Function executed on TxNextPacket Timeout event
+ */
+static void OnTxNextPacketTimerEvent( void )
+{
+    TimerStop( &TxNextPacketTimer );
+    TxNextPacket = true;
+}
+
+/*!
+ * \brief Function executed on Led 1 Timeout event
+ */
+static void OnLed1TimerEvent( void )
+{
+    TimerStop( &Led1Timer );
+    Led1StateChanged = true;
+}
+
+/*!
+ * \brief Function executed on Led 2 Timeout event
+ */
+static void OnLed2TimerEvent( void )
+{
+    TimerStop( &Led2Timer );
+    Led2StateChanged = true;
+}
+
+/*!
+ * \brief Function to be executed on MAC layer event
+ */
+static void OnMacEvent( LoRaMacEventFlags_t *flags, LoRaMacEventInfo_t *info )
+{
+    if( flags->Bits.JoinAccept == 1 )
+    {
+#if( OVER_THE_AIR_ACTIVATION != 0 )
+        TimerStop( &JoinReqTimer );
+#endif
+        IsNetworkJoined = true;
+        IsNetworkJoinedStatusUpdate = true;
+    }
+    else
+    {
+        if( flags->Bits.Tx == 1 )
+        {
+        }
+
+        if( flags->Bits.Rx == 1 )
+        {
+            if( flags->Bits.RxData == true )
+            {
+                ProcessRxFrame( flags, info );
+            }
+            
+            LoRaMacDownlinkStatus.Rssi = info->RxRssi;
+            if( info->RxSnr & 0x80 ) // The SNR sign bit is 1
+            {
+                // Invert and divide by 4
+                LoRaMacDownlinkStatus.Snr = ( ( ~info->RxSnr + 1 ) & 0xFF ) >> 2;
+                LoRaMacDownlinkStatus.Snr = -LoRaMacDownlinkStatus.Snr;
+            }
+            else
+            {
+                // Divide by 4
+                LoRaMacDownlinkStatus.Snr = ( info->RxSnr & 0xFF ) >> 2;
+            }
+            LoRaMacDownlinkStatus.DownlinkCounter++;
+            LoRaMacDownlinkStatus.RxData = flags->Bits.RxData;
+            LoRaMacDownlinkStatus.Port = info->RxPort;
+            LoRaMacDownlinkStatus.Buffer = info->RxBuffer;
+            LoRaMacDownlinkStatus.BufferSize = info->RxBufferSize;
+            
+            LoRaMacUplinkStatus.Acked = info->TxAckReceived;
+            LoRaMacUplinkStatus.Datarate = info->TxDatarate;
+            LoRaMacUplinkStatus.UplinkCounter = LoRaMacGetUpLinkCounter( ) - 1;
+            
+            LinkStatusUpdated = true;
+            TimerStart( &Led2Timer );
+        }
+    }
+    // Schedule a new transmission
+    ScheduleNextTx = true;
+}
+
+/**
+ * Main application entry point.
+ */
+int main( void )
+{
+    SerialDisplayInit( );
+    
+#if( OVER_THE_AIR_ACTIVATION != 0 )
+    uint8_t sendFrameStatus = 0;
+#endif
+    bool trySendingFrameAgain = false;
+
+    BoardInit( );
+
+    LoRaMacEvents.MacEvent = OnMacEvent;
+    LoRaMacInit( &LoRaMacEvents, &BoardGetBatterieLevel );
+
+    IsNetworkJoined = false;
+
+    SerialDisplayUpdateActivationMode( OVER_THE_AIR_ACTIVATION );
+    
+#if( OVER_THE_AIR_ACTIVATION == 0 )
+    LoRaMacInitNwkIds( LORAWAN_NETWORK_ID, LORAWAN_DEVICE_ADDRESS, NwkSKey, AppSKey );
+    IsNetworkJoined = true;
+    
+    SerialDisplayUpdateNwkId( LORAWAN_NETWORK_ID );
+    SerialDisplayUpdateDevAddr( LORAWAN_DEVICE_ADDRESS );
+    SerialDisplayUpdateKey( 12, NwkSKey );
+    SerialDisplayUpdateKey( 13, AppSKey );
+#else
+    // Sends a JoinReq Command every 5 seconds until the network is joined
+    TimerInit( &JoinReqTimer, OnJoinReqTimerEvent ); 
+    TimerSetValue( &JoinReqTimer, OVER_THE_AIR_ACTIVATION_DUTYCYCLE );
+    
+    SerialDisplayUpdateEui( 5, DevEui );
+    SerialDisplayUpdateEui( 6, AppEui );
+    SerialDisplayUpdateKey( 7, AppKey );
+
+#endif
+
+    SerialDisplayUpdateNetworkIsJoined( IsNetworkJoined );
+
+    TxNextPacket = true;
+    TimerInit( &TxNextPacketTimer, OnTxNextPacketTimerEvent );
+    
+    TimerInit( &Led1Timer, OnLed1TimerEvent );
+    TimerSetValue( &Led1Timer, 500000 );
+
+    TimerInit( &Led2Timer, OnLed2TimerEvent );
+    TimerSetValue( &Led2Timer, 500000 );
+
+    LoRaMacSetAdrOn( LORAWAN_ADR_ON );
+    LoRaMacTestSetDutyCycleOn( LORAWAN_DUTYCYCLE_ON );
+    LoRaMacSetPublicNetwork( LORAWAN_PUBLIC_NETWORK );
+
+    SerialDisplayUpdateAdr( LORAWAN_ADR_ON );
+    SerialDisplayUpdateDutyCycle( LORAWAN_DUTYCYCLE_ON );
+    SerialDisplayUpdatePublicNetwork( LORAWAN_PUBLIC_NETWORK );
+    
+    LoRaMacDownlinkStatus.DownlinkCounter = 0;
+
+    while( 1 )
+    {
+        while( IsNetworkJoined == false )
+        {
+#if( OVER_THE_AIR_ACTIVATION != 0 )
+            if( TxNextPacket == true )
+            {
+                TxNextPacket = false;
+                
+                sendFrameStatus = LoRaMacJoinReq( DevEui, AppEui, AppKey );
+                switch( sendFrameStatus )
+                {
+                case 1: // BUSY
+                    break;
+                case 0: // OK
+                case 2: // NO_NETWORK_JOINED
+                case 3: // LENGTH_PORT_ERROR
+                case 4: // MAC_CMD_ERROR
+                case 6: // DEVICE_OFF
+                default:
+                    // Relaunch timer for next trial
+                    TimerStart( &JoinReqTimer );
+                    break;
+                }
+            }
+            SerialRxProcess( );
+#endif
+        }
+
+        SerialRxProcess( );
+        
+        if( IsNetworkJoinedStatusUpdate == true )
+        {
+            IsNetworkJoinedStatusUpdate = false;
+            SerialDisplayUpdateNetworkIsJoined( IsNetworkJoined );
+        }
+        if( Led1StateChanged == true )
+        {
+            Led1StateChanged = false;
+            SerialDisplayUpdateLedState( 1, 0 );
+        }
+        if( Led2StateChanged == true )
+        {
+            Led2StateChanged = false;
+            SerialDisplayUpdateLedState( 2, 0 );
+        }
+        if( Led3StateChanged == true )
+        {
+            Led3StateChanged = false;
+            SerialDisplayUpdateLedState( 3, AppLedStateOn );
+        }
+        if( LinkStatusUpdated == true )
+        {
+            LinkStatusUpdated = false;
+            SerialDisplayUpdateLedState( 2, 1 );
+            SerialDisplayUpdateUplink( LoRaMacUplinkStatus.Acked, LoRaMacUplinkStatus.Datarate, LoRaMacUplinkStatus.UplinkCounter, LoRaMacUplinkStatus.Port, LoRaMacUplinkStatus.Buffer, LoRaMacUplinkStatus.BufferSize );
+            SerialDisplayUpdateDownlink( LoRaMacDownlinkStatus.RxData, LoRaMacDownlinkStatus.Rssi, LoRaMacDownlinkStatus.Snr, LoRaMacDownlinkStatus.DownlinkCounter, LoRaMacDownlinkStatus.Port, LoRaMacDownlinkStatus.Buffer, LoRaMacDownlinkStatus.BufferSize );
+        }
+
+        if( ScheduleNextTx == true )
+        {
+            ScheduleNextTx = false;
+            // Schedule next packet transmission
+            TxDutyCycleTime = APP_TX_DUTYCYCLE + randr( -APP_TX_DUTYCYCLE_RND, APP_TX_DUTYCYCLE_RND );
+            TimerSetValue( &TxNextPacketTimer, TxDutyCycleTime );
+            TimerStart( &TxNextPacketTimer );
+        }
+
+        if( trySendingFrameAgain == true )
+        {
+            trySendingFrameAgain = SendFrame( );
+        }
+        if( TxNextPacket == true )
+        {
+            TxNextPacket = false;
+        
+            SerialDisplayUpdateDonwlinkRxData( false );
+            
+            PrepareTxFrame( LORAWAN_APP_PORT );
+            
+            SerialDisplayUpdateLedState( 1, 1 );
+            TimerStart( &Led1Timer );
+
+            trySendingFrameAgain = SendFrame( );
+            
+            SerialDisplayUpdateUplink( LoRaMacUplinkStatus.Acked, LoRaMacUplinkStatus.Datarate, LoRaMacUplinkStatus.UplinkCounter, LoRaMacUplinkStatus.Port, LoRaMacUplinkStatus.Buffer, LoRaMacUplinkStatus.BufferSize );
+        }
+    }
+}