Dear Support Team,
In the project, I'm working on thingy91:nrf9160 board. Our test case scenario is to connect to cellular network(NB-IoT) and acquire GPS fix for which we are following the steps as mentioned below:
1. Initialize the modem library
2. Register to network and connect to mobile network (NB-IoT)
3. Acquire GPS fixe using A-GPS services (i.e. from nrf-cloud) using external antenna
4. After GPS is acquired de-initialize the modem library and unregister from mobile network
5. Enter into sleep mode using k_sleep functionality for time being consider device stay in sleep state for 30min
6. Device wakes up from sleep after defined time interval and continues the cycle from step-1 onwards
We have successfully implemented the above test scenario on the Thingy:91 (nRF9160) board. Thus, resulting in achieving consistent network connectivity and GPS performance.
Below are the relevant configurations from our prj.conf file, used for the Thingy:91 with an external GNSS antenna and the onboard LTE antenna:
# LTE Link Control CONFIG_LTE_LINK_CONTROL=y # For using NbIoT network CONFIG_LTE_MODE_PREFERENCE_NBIOT=y #Disable this config to use the onboard antenna CONFIG_MODEM_ANTENNA_GNSS_EXTERNAL=y CONFIG_MODEM_ANTENNA_AT_MAGPIO="AT%XMAGPIO=1,1,1,7,1,746,803,2,698,748,2,1710,2200,3,824,894,4,880,960,5,791,849,7,1565,1586" CONFIG_MODEM_ANTENNA_AT_COEX0="AT%XCOEX0"
We are now porting the firmware to the nRF9151-DK board. However, when using the same configuration as prj.conf for external GNSS antenna and onboard LTE antenna, the DK board connects to NB-IoT network for first 3-4 times and then doesn't connect to cellular network even if we:
1. Turn off and then turn on the DK board.
2. Plug out/in the USB cable.
3. Flash the same firmware onto the board.
The nrf9151 DK board only connects back to NB-IoT network if same SIM which was inserted on thingy91:nrf9160 and which connects to NB-IoT mobile network is inserted on nrf9151 DK board.
We understand that the Thingy:91 uses a single antenna time-shared between GNSS and cellular network(NB-IoT), whereas the nRF9151-DK has separate antennas for GNSS and cellular network. So for thingy91 we were setting the MAGPIO for using GNSS and cellular network on time sharing basis.
thingy91-9160 GNSS and LTE antenna
nrf9151 DK GNSS and LTE antenna
Could you please advise on the necessary configuration changes required for the nRF9151-DK to ensure consistent NB-IoT connectivity?
Do let me know if you require any further information to guide me regarding the above query.
Best Regards,
Mahima
