Define how to connect to NB-IoT on Three network in Hong Kong

[Saketaram]

Hi,

I am now in Hong Kong, and trying to connect to NB-IoT network here. There are 2 providers of NB-IoT in Hong Kong: "CMHK" and "Three". They provide NB-IoT since 2017 in the region.

I have a 4.5G sim card on Three for my smartphone: so I plugged it into the nRF9160-DK (with at_client firmware, after a nrfjprog -e, and a clean build and flash), and run LTE Link Monitor.

4.5G is supposed to offer NB-IoT as well as regular LTE, and functionalities of 5G.

I get the following AT+CFUN?

Do you see what I need to modify?

AT+CFUN?
+CFUN: 0
OK
AT+CFUN=1
OK
AT+CFUN?
+CFUN: 1
OK
AT+CGSN=1
+CGSN: "352656100221848"
OK
AT+CGMI
Nordic Semiconductor ASA
OK
AT+CGMM
nRF9160-SICA
OK
AT+CGMR
mfw_nrf9160_1.1.1
OK
AT+CEMODE?
+CEMODE: 2
OK
AT%XCBAND=?
%XCBAND: (1,2,3,4,5,8,12,13,14,17,18,19,20,25,26,28,66)
OK
AT+CMEE?
+CMEE: 0
OK
AT+CMEE=1
OK
AT+CNEC?
+CNEC: 0
OK
AT+CNEC=24
OK
AT+CGEREP?
+CGEREP: 0,0
OK
AT+CGDCONT?
OK
AT+CGACT?
OK
AT+CGEREP=1
OK
AT+CIND=1,1,1
OK
AT+CEREG=2
OK
AT+CEREG?
+CEREG: 2,4,"FFFE","FFFFFFFF",7
OK
AT%CESQ=1
OK
AT+CESQ
+CESQ: 99,99,255,255,255,255
OK
AT%XSIM=1
OK
AT%XSIM?
%XSIM: 1
OK
AT+CPIN?
+CPIN: READY
OK
AT+CPINR="SIM PIN"
+CPINR: "SIM PIN",3
OK
AT+CIMI
454030010286363
OK

When I modify AT+CGDCONT as follows, PDN becomes Green, when LTE still blinks Yellow/Red 

AT+CGDCONT=0, "IP", "mobile.three.com.hk"
OK
AT+CGDCONT?
+CGDCONT: 0,"IP","mobile.three.com.hk","",0,0
OK

Is there another setup I am missing, with the AT instructions, to enable the LTE-M or NB-IoT?

Best regards,

[Hakon]

Hello,

you need to put the modem in NB-IoT mode to be able to connect to an NB-IoT network. Are you doing that? You can set the mode by using the xsystemmode command.

[Saketaram]

Hi Hakon,

I just received the sim cards from Three in Hong Kong, one of the 2 providers of NB-IoT service in Hong Kong. The cards were activated and I followed your advice, by switching to LTE-CatNB1. I could  go further:

*** Booting Zephyr OS build v2.1.0-ncs1-snapshot1  ***
The AT host sample started
AT%XSYSTEMMODE?
%XSYSTEMMODE: 1,0,0,0
OK
AT+CFUN=4
OK
AT%XSYSTEMMODE=0,1,1,0
OK
AT%XSYSTEMMODE?
%XSYSTEMMODE: 0,1,1,0
OK
AT+CFUN=1
OK
AT+CFUN?
+CFUN: 1
OK
AT+CGSN=1
+CGSN: "352656100221848"
OK
AT+CGMI
Nordic Semiconductor ASA
OK
AT+CGMM
nRF9160-SICA
OK
AT+CGMR
mfw_nrf9160_1.1.1
OK
AT+CEMODE?
+CEMODE: 0
OK
AT%XCBAND=?
%XCBAND: (1,2,3,4,5,8,12,13,17,19,20,25,26,28,66)
OK
AT+CMEE?
+CMEE: 0
OK
AT+CMEE=1
OK
AT+CNEC?
+CNEC: 0
OK
AT+CNEC=24
OK
AT+CGEREP?
+CGEREP: 0,0
OK
AT+CGDCONT?
OK
AT+CGACT?
OK
AT+CGEREP=1
OK
AT+CIND=1,1,1
OK
AT+CEREG=2
OK
AT+CEREG?
+CEREG: 2,4,"FFFE","FFFFFFFF",9
OK
AT%CESQ=1
OK
AT+CESQ
+CESQ: 99,99,255,255,255,255
OK
AT%XSIM=1
OK
AT%XSIM?
%XSIM: 1
OK
AT+CPIN?
+CPIN: READY
OK
AT+CPINR="SIM PIN"
+CPINR: "SIM PIN",3
OK
AT+CIMI
454035000002631
OK
%CESQ: 72,3,25,3
+CEREG: 2,"0BF4","099E5765",9
+CGEV: ME PDN ACT 0,0
AT+CGDCONT?
+CNEC_ESM: 50,0
+CEREG: 1,"0BF4","099E5765",9
+CIND: "service",1
+CGDCONT: 0,"IP","3HK.IOT","10.224.3.28",0,0
OK
AT+CGACT?
+CGACT: 0,1
OK
%CESQ: 72,3,17,2
%CESQ: 72,3,24,3
%CESQ: 72,3,17,2
%CESQ: 72,3,24,3
%CESQ: 67,3,24,3
%CESQ: 67,3,29,4

The screen shows:

But still, the "LTE" indicator on the top right of the screen is blinking Yellow/Red continuously, even after 10 minutes.

Anything missing in this configuration?

Thanks in advance.

[Hakon]

The "LTE" indicator is unrealiable and doesn't really show whether you're connected or not. The device seems to be properly connected.

[Saketaram]

Hi Hakon,

After rebooting and setting up again AT%XSYSTEMMODE=0,1,1,2
it worked:

Thanks for the setup information!