Hello,
I am using LoraWan as part of a study project. I am constantly facing problems with unstable connection. I don’t have my own Gateway, but the university has several available. Being close to the gateway I am getting “no JoinAccept”. There is constant confirmation in the console of ttn that the join-request is received and redirected. Sometimes (very rarely) the connection is established. Uplink works mostly fine, but downlink has systematic problems. Out of ~100 cases downlink was received only twice. Can you please tell me where the problem may lie?
My device: arduino Uno with Dragino Lora Bee v1.1 module. As code I use the standard example from the LMIC library with some modifications to decode the downlink.
/*******************************************************************************
#include <lmic.h>
#include <hal/hal.h>
#include <SPI.h>
//
// For normal use, we require that you edit the sketch to replace FILLMEIN
// with values assigned by the TTN console. However, for regression tests,
// we want to be able to compile these scripts. The regression tests define
// COMPILE_REGRESSION_TEST, and in that case we define FILLMEIN to a non-
// working but innocuous value.
//
#ifdef COMPILE_REGRESSION_TEST
# define FILLMEIN 0
#else
# warning "You must replace the values marked FILLMEIN with real values from the TTN control panel!"
# define FILLMEIN (#dont edit this, edit the lines that use FILLMEIN)
#endif
// This EUI must be in little-endian format, so least-significant-byte
// first. When copying an EUI from ttnctl output, this means to reverse
// the bytes. For TTN issued EUIs the last bytes should be 0xD5, 0xB3,
// 0x70.
static const u1_t PROGMEM APPEUI[8]={ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
void os_getArtEui (u1_t* buf) { memcpy_P(buf, APPEUI, 8);}
// This should also be in little endian format, see above.
static const u1_t PROGMEM DEVEUI[8]={ 0x24, 0xB8, 0x06, 0xD0, 0x7E, 0xD5, 0xB3, 0x70 };
void os_getDevEui (u1_t* buf) { memcpy_P(buf, DEVEUI, 8);}
// This key should be in big endian format (or, since it is not really a
// number but a block of memory, endianness does not really apply). In
// practice, a key taken from ttnctl can be copied as-is.
static const u1_t PROGMEM APPKEY[16] = { 0x76, 0x06, 0x85, 0x09, 0x14, 0x41, 0x47, 0xAF, 0x60, 0xF0, 0x3A, 0x3A, 0xFE, 0x18, 0x9F, 0x33 };
void os_getDevKey (u1_t* buf) { memcpy_P(buf, APPKEY, 16);}
static uint8_t mydata[] = "Hello, world!";
static osjob_t sendjob;
// Schedule TX every this many seconds (might become longer due to duty
// cycle limitations).
const unsigned TX_INTERVAL = 60;
// Pin mapping
const lmic_pinmap lmic_pins = {
.nss = 10,
.rxtx = LMIC_UNUSED_PIN,
.rst = 9,
.dio = {2, 6, 7}, // Specify pin numbers for DIO0, 1, 2
};
void printHex2(unsigned v) {
v &= 0xff;
if (v < 16)
Serial.print('0');
Serial.print(v, HEX);
}
void onEvent (ev_t ev) {
Serial.print(os_getTime());
Serial.print(": ");
switch(ev) {
case EV_SCAN_TIMEOUT:
Serial.println(F("EV_SCAN_TIMEOUT"));
break;
case EV_BEACON_FOUND:
Serial.println(F("EV_BEACON_FOUND"));
break;
case EV_BEACON_MISSED:
Serial.println(F("EV_BEACON_MISSED"));
break;
case EV_BEACON_TRACKED:
Serial.println(F("EV_BEACON_TRACKED"));
break;
case EV_JOINING:
Serial.println(F("EV_JOINING"));
break;
case EV_JOINED:
Serial.println(F("EV_JOINED"));
{
u4_t netid = 0;
devaddr_t devaddr = 0;
u1_t nwkKey[16];
u1_t artKey[16];
LMIC_getSessionKeys(&netid, &devaddr, nwkKey, artKey);
Serial.print("netid: ");
Serial.println(netid, DEC);
Serial.print("devaddr: ");
Serial.println(devaddr, HEX);
Serial.print("AppSKey: ");
for (size_t i=0; i<sizeof(artKey); ++i) {
if (i != 0)
Serial.print("-");
printHex2(artKey[i]);
}
Serial.println("");
Serial.print("NwkSKey: ");
for (size_t i=0; i<sizeof(nwkKey); ++i) {
if (i != 0)
Serial.print("-");
printHex2(nwkKey[i]);
}
Serial.println();
}
// Disable link check validation (automatically enabled
// during join, but because slow data rates change max TX
// size, we don't use it in this example.
LMIC_setLinkCheckMode(0);
break;
/*
|| This event is defined but not used in the code. No
|| point in wasting codespace on it.
||
|| case EV_RFU1:
|| Serial.println(F("EV_RFU1"));
|| break;
*/
case EV_JOIN_FAILED:
Serial.println(F("EV_JOIN_FAILED"));
break;
case EV_REJOIN_FAILED:
Serial.println(F("EV_REJOIN_FAILED"));
break;
case EV_TXCOMPLETE:
Serial.println(F("EV_TXCOMPLETE (includes waiting for RX windows)"));
if (LMIC.txrxFlags & TXRX_ACK)
Serial.println(F("Received ack"));
if (LMIC.dataLen) {
Serial.print(F("Received "));
Serial.print(LMIC.dataLen);
Serial.println(F(" bytes of payload"));
// Convert received bytes to a string
char receivedMessage[LMIC.dataLen + 1]; // +1 for null terminator
for (int i = 0; i < LMIC.dataLen; i++) {
receivedMessage[i] = (char)LMIC.frame[LMIC.dataBeg + i];
}
receivedMessage[LMIC.dataLen] = '\0'; // Null-terminate the string
// Print the received message as a string
Serial.print(F("Message: "));
Serial.println(receivedMessage);
// Schedule next transmission
os_setTimedCallback(&sendjob, os_getTime()+sec2osticks(TX_INTERVAL), do_send);
}
break;
case EV_LOST_TSYNC:
Serial.println(F("EV_LOST_TSYNC"));
break;
case EV_RESET:
Serial.println(F("EV_RESET"));
break;
case EV_RXCOMPLETE:
// data received in ping slot
Serial.println(F("EV_RXCOMPLETE"));
break;
case EV_LINK_DEAD:
Serial.println(F("EV_LINK_DEAD"));
break;
case EV_LINK_ALIVE:
Serial.println(F("EV_LINK_ALIVE"));
break;
/*
|| This event is defined but not used in the code. No
|| point in wasting codespace on it.
||
|| case EV_SCAN_FOUND:
|| Serial.println(F("EV_SCAN_FOUND"));
|| break;
*/
case EV_TXSTART:
Serial.println(F("EV_TXSTART"));
break;
case EV_TXCANCELED:
Serial.println(F("EV_TXCANCELED"));
break;
case EV_RXSTART:
/* do not print anything -- it wrecks timing */
break;
case EV_JOIN_TXCOMPLETE:
Serial.println(F("EV_JOIN_TXCOMPLETE: no JoinAccept"));
break;
default:
Serial.print(F("Unknown event: "));
Serial.println((unsigned) ev);
break;
}
}
void do_send(osjob_t* j){
// Check if there is not a current TX/RX job running
if (LMIC.opmode & OP_TXRXPEND) {
Serial.println(F("OP_TXRXPEND, not sending"));
} else {
// Prepare upstream data transmission at the next possible time.
LMIC_setTxData2(1, mydata, sizeof(mydata)-1, 0);
Serial.println(F("Packet queued"));
}
// Next TX is scheduled after TX_COMPLETE event.
}
void setup() {
Serial.begin(9600);
Serial.println(F("Starting"));
#ifdef VCC_ENABLE
// For Pinoccio Scout boards
pinMode(VCC_ENABLE, OUTPUT);
digitalWrite(VCC_ENABLE, HIGH);
delay(1000);
#endif
// LMIC init
os_init();
// Reset the MAC state. Session and pending data transfers will be discarded.
LMIC_reset();
// Start job (sending automatically starts OTAA too)
do_send(&sendjob);
}
void loop() {
os_runloop_once();
}
) - please review the FUP in the Learn section (linked above) and reassure us that you are on top of this aspect, particularly the number of downlinks you can do a day.