Test Results and Inquiries Regarding Connection Issues with HL7800 Module to Private LTE Network

IoT Modules HL78
1

Hi,
We used your HL7800 module to connect our IoT device to a self-owned LTE network within a plant, rather than a commercial service-providing telecom. Over the past two weeks, we conducted tests using two HL7800EV-V1.2.1 units supplied by your company.

The self-owned LTE network of our customer operates on Band 28 with an uplink frequency of 718-728MHz and a downlink frequency of 773-783MHz. We received USIM chips and APNs from our customer. While other terminals from different companies are successfully connected to this LTE network, our testing HL7800EV boards are experiencing connectivity issues.

Operation on a commercial LTE network other than a private LTE network is without any issues.

Is the HL7800 compatible with LTE BAND28 for commercial use? If not, please recommend another module. Our device under development operates with a single AAA battery, so it cannot accommodate modules with large physical dimensions. Are there any additional settings required for connecting the HL7800 to a private LTE network besides the frequency band?

The network administrator did not request the IMEI value or any other registration information for the HL7800EV board.

Here are the test results available for reference.

ATI
HL7800
OK

AT+CPIN?
+CPIN: READY
OK

AT+CGDCONT?
+CGDCONT: 1,“IPV4V6”,“lte.hxxxxit.com”,0,0,0,
+CGDCONT: 2,“IPV4V6”,0,0,0,0,0,0,
OK

AT+KSIMSEL?
+KSIMSEL: 0,1
OK

AT+KSRAT?
+KSRAT: 0
OK

AT+KCARRIERCFG?
+KCARRIERCFG: 0
OK

AT+KBND?
+KBND: 0,00000000000000000004
OK

AT+KBNDCFG?
+KBNDCFG: 0,00000000000008000000
+KBNDCFG: 1,00000000000008000000
+KBNDCFG: 2,0
OK

AT+CIMI
450300010204955
OK

AT+CFUN?
+CFUN: 1
OK

…

AT+CFUN=1,1
OK

+CEREG: 0
+CREG: 0
+CEREG: 2
+CEREG: 0
+CEREG: 2
+CEREG: 0
+CEREG: 2
+CEREG: 0
+CEREG: 2
+CEREG: 0
+CEREG: 2

///1minute after
AT+KBND?
+KBND: 0,00000000000000000000
OK

+CEREG: 0

AT+KBNDCFG?
+KBNDCFG: 0,00000000000008000000
+KBNDCFG: 1,00000000000008000000
+KBNDCFG: 2,0

OK

ATI9
HL7800.4.7.1
HL78xx.4.7.1.0.RK_02_01_02_00_153.20230620
2023/06/20 06:48:03
IMEI-SV: 3546160911877919
Legato RTOS: 18.09.6.ALT1250.rc12 2023/06/20 02:53:04
atSwi: 18.09
UBOOT: 01.03
Apps: RKAPP_02_01_02_00_129__96afe6c8fdf77327e86cfbe69d5cd6cdd4af3a89
MAC: ALT1250_02_01_02_00_138_FW
PHY: 12.50.315454
PMP: 315913
SBUB: 1
SBFW: 1
RPuK: 53F7A48A
FPuK: 139A8E70
RBUB: 0
RBFW: 0
OK

2

Hi @helloearth7,

Could you please take a look at the below question/concern and share your answers?

  • Please make sure the antenna are properly connected to the module and the signal strength is good.

  • Also, make sure the APN is set correctly.

  • You mentioned that other devices have successfully connected to the LTE network with Uplink frequency: 718-728 MHz and Downlink frequency: 773-783 MHz. So, what RAT (Radio Access Technology) is the device you mentioned using?

  • Does your self-owned LTE network support RAT Cat-M? Because I noticed that you configured the HL7800 to use RAT Cat-M

Thanks,

3

Hi jerdung,

  • Please make sure the antenna are properly connected to the module and the signal strength is good.
  • Also, make sure the APN is set correctly.

We were able to confirm that there are no issues with the antenna and APN settings. The Samsung device currently being used at the plant connects and operates without any problems. We conducted tests by inserting the USIM used in the Samsung device into the HL7800EV board we are testing. Although the APN settings were accurate, we were unable to establish a connection.

  • You mentioned that other devices have successfully connected to the LTE network with Uplink frequency: 718-728 MHz and Downlink frequency: 773-783 MHz. So, what RAT (Radio Access Technology) is the device you mentioned using?
  • Does your self-owned LTE network support RAT Cat-M? Because I noticed that you configured the HL7800 to use RAT Cat-M

We have tested the HL7800EV board in LTE Cat.M1 mode. However, the Samsung Galaxy device being used at the plant is utilizing a different RAT.
Although we were informed by the network administrator that their Network Unit and Radio Unit support 3GPP Release 13 and also LTE Cat.M1, we are unsure if their LTE network is configured to enable Cat.M1 usage.

Thanks.

4

Hi @helloearth7,

Please double check carefully that your self-owned LTE network supports Cat-M before testing the HL7800 in Cat-M mode.

Thanks,

5

Thanks,
I will check today.