Assistance Needed for LoRa 2.4GHz Configuration and Join Request Issues

[sluissantos]

Hello,

I am working on a project using LoRa 2.4GHz and need some assistance with configuration and performance.

Here are the details of my setup:

• Development Environment: SES 8.18, nRF5 SDK Version 17.1, nRF52832.
• Transceiver: E28-2G4M12S (SX1280).
• Gateway: MikroTik wAP LR2 kit.

I am adapting the example from application_example/2_porting_nrf_52840 to work with the nRF52832. For testing, I am using the file main_periodical_uplink.c and here is the output I get:

<info> app: INFO: Modem Initialization
<info> app: INFO: Use soft secure element for cryptographic functionalities
<info> app: stack_id 0
<info> app: DevNonce = 0
<info> app: JoinNonce = 0xff ff ff, NetID = 0xff ff ff
<info> app: Region = WW2G4
<info> app: LoRaWAN Certification is disabled on stack 0
<info> app: Modem event callback
<info> app: INFO: Event received: RESET
<info> app: INFO: smtc_modem_join_network
<info> app: Start a new join sequence in 3 seconds on stack 0
<info> app: INFO: Periodical uplink example is starting 
<info> app: STMC_MODEM_STATUS = 0
<info> app: INFO: No network joined yet or unknown status
<info> app: STMC_MODEM_STATUS = 0
<info> app: INFO: No network joined yet or unknown status
<info> app: DevEUI - (8 bytes): 00 00 00 00 00 00 00 00
<info> app: JoinEUI - (8 bytes): 00 00 00 00 00 00 00 00
<info> app: DevNonce 0x1, stack_id 0
<info> app: INFO: SMTC_MODEM_STATUS_JOINING
<info> app: *************************************
<info> app: Send Payload  for stack_id = 0
<info> app: *************************************
<info> app: Tx LoRa at 9014 ms: freq:2479000000, SF10, BW800, len 23 bytes 8 dBm, fcnt_up 0, toa = 75
<info> app: INFO: SMTC_MODEM_STATUS_JOINING
<info> app: INFO: SMTC_MODEM_STATUS_JOINING

While monitoring the traffic on my gateway, I rarely receive the join request message. When I do receive it, the RSSI is usually below -100 dBm, which indicates poor signal strength.

Here are my gateway configurations:

• General settings:
  

• Channels (all configured to SF12):
  

• Join messsage (very rarely) receiveed:
  

I am trying to ensure that I can successfully send messages.

My questions:

1. How can I configure the radio to always use Spreading Factor 12 (SF12) (along with all other radio parameters), even for the join request message?
2. The RSSI is consistently low. What could be the possible cause for this poor signal quality?

Thank you for your help!

[opeyrard]

Hi,
Could you please compile using flag LBM_BUILD_OPTIONS +=WW2G4_SINGLE_DATARATE ? In this case, DR0 will be taken into consideration for all uplinks.
Please check and let us know.
Many thanks,

[sluissantos]

The issue is that my tasks were not running.

Now, I can send uplinks, but I get the following error in the ChirpStack Gateway Bridge logs:

nov 21 10:32:51 santos chirpstack-gateway-bridge[35649]: {"addr":{"IP":"192.168.88.1","Port":57128,"Zone":""},"data_base64":"AgGpAJNX70hTWDU5eyJyeHBrIjpbeyJjaGFuIjoxLCJjb2RyIjoiT0ZGIiwiZGF0YSI6IiIsImRhdHIiOiJTRjEyQlc4MTIiLCJmb2ZmIjotMTkwNTQ2LCJmcmVxIjoyNDc5LjAwMDAwMCwibHNuciI6LTI0LjAwMDAwMCwibW9kdSI6IkxPUkEiLCJyc3NpIjotMTA0LCJzaXplIjowLCJzdGF0IjoxLCJ0bXN0Ijo0NDUwNjc1NDR9XX0=","error":"get uplink frames error: backend/semtechudp/packets: get uplink frame error: backend/semtechudp:packets: invalid CodR: OFF","level":"error","msg":"backend/semtechudp: could not handle packet","time":"2024-11-21T10:32:51-03:00"}

I’ve tried different Coding Rates, but the error persists.

On the log application, i got the log:

`info> app: �[0m
app: User LoRaWAN tx on FPort 101

app:

---

app: Send Payload for stack_id = 0
app:

---

app: Tx LoRa at 14303 ms: freq:2403000000, SF12, BW800, len 17 bytes 8 dBm, fcnt_up 0, toa = 244, CR=3

app:
app: RP: Task #1 enqueue with #7 priority

app:
app: RP: Arbiter has been called by rp_task_enqueue and app:
app: RP: High priority task is in the future

app:
app: RP: Arbiter has been called by rp_timer_irq and priority-task #1, timer hook #1, delay 10, now 14293

app:
app: RP: Launch task #1 and start radio state 2, type 2

app:
app:
RP- INFO - Radio task #1 running - Timer task #1 running - Hook ID #1 -
app:
app: TASK_TX_LORA
app:
app: - start time @14303 - priority #7

app:
app: RP: INFO - Radio IRQ received for hook #1

app: RP_STATUS_RX_CRC_ERROR

app:
app: RP: No more active tasks

app:

---

app: TX DONE
app:

---

app: rx_start_target -> datarate:0, rx_window_symb:6, rx_offset_ms:4, board_delay_ms:1

app:

---

app: RX1 Timeout for stack_id = 0
app:

---

offset_ms:4, board_delay_ms:1

app:

---

app: RX2 Timeout for stack_id = 0
app:

---

app: �[0;34mModem event callback
�[0m
app: �[0;32mINFO: Event received: TXDONE
`

[opeyrard]

Hi,
The Coding Rate (CR3) used seems wrong. This should be Coding Rate 4/8, which corresponds to CR7 in the RAL.
For more details, please refer to https://github.com/Lora-net/SWL2001/blob/master/lbm_lib/smtc_modem_core/lr1mac/src/smtc_real/src/region_ww2g4_defs.h

Could you please try and let us know ?
Many thanks,