IR302 connection speed reduces over time

Cellular Modems
1
Hello,

We are using the IR302 LTE modem with the Peplink Mobility 22G antenna in a stationary setup and we are getting good connection speed (downlink and uplink) for a while, but over time (on the order of 30 minutes to 1 hour) the connection speed reduces. Eventually the modem will select a weaker tower and the speeds get even worse. If we reboot the modem it will start with good connection speeds, and then reduce over time again.

We noticed that this issue seems to be somewhat correlated to CPU usage. It slowly increases up to 1.00, which we are guessing is 100% CPU usage?

Here is some data we have collected over the last few days:

10-19-20248:31 AM10/19/2024 8:31:0022.8016.40This is the new router/antenna antenna setup
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-19-20248:34 AM10/19/2024 8:34:0024.7016.90

LTE B5 (824 – 849 UL / 869 – 894 DL)
10-19-20248:40 AM10/19/2024 8:40:0024.0011.20CPU Load (1 / 5 / 15 mins): 0.97 / 0.93 / 0.62
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-19-20248:49 AM10/19/2024 8:49:0024.800.08CPU Load (1 / 5 / 15 mins): 1.01 / 0.96 / 0.74
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-19-20248:50 AM10/19/2024 8:50:0024.800.08CPU Load (1 / 5 / 15 mins): 0.93 / 0.94 / 0.76
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-19-202410:03 AM10/19/2024 10:03:007.960.08CPU Load (1 / 5 / 15 mins): 0.84 / 0.95 / 0.95
LTE B2 (1850 – 1910 UL / 1930 – 1990 DL)
10-20-202410:02 AM10/20/2024 10:02:009.760.08CPU Load (1 / 5 / 15 mins): 1.04 / 1.02 / 0.97
LTE B2 (1850 – 1910 UL / 1930 – 1990 DL)
10-20-202410:35 AM10/20/2024 10:35:005.096.67CPU Load (1 / 5 / 15 mins): 1.04 / 0.88 / 0.73
LTE B2 (1850 – 1910 UL / 1930 – 1990 DL)
10-20-202410:38 AM10/20/2024 10:38:0011.006.68CPU Load (1 / 5 / 15 mins): 0.67 / 0.82 / 0.73
LTE B2 (1850 – 1910 UL / 1930 – 1990 DL)
10-21-202411:45 AM10/21/2024 11:45:000.970.08CPU Load (1 / 5 / 15 mins): 0.97 / 0.95 / 0.95
LTE B2 (1850 – 1910 UL / 1930 – 1990 DL)
10-21-202411:50 AM10/21/2024 11:50:0020.202.54rebooted modem CPU Load (1 / 5 / 15 mins): 0.80 / 0.44 / 0.17
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-202411:55 AM10/21/2024 11:55:0022.1011.30CPU Load (1 / 5 / 15 mins): 0.57 / 0.50 / 0.29
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-202411:58 AM10/21/2024 11:58:0019.200.08CPU Load (1 / 5 / 15 mins): 0.48 / 0.50 / 0.32
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-202412:00 PM10/21/2024 12:00:0019.400.08CPU Load (1 / 5 / 15 mins): 0.49 / 0.51 / 0.34
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-202412:05 PM10/21/2024 12:05:0024.700.08CPU Load (1 / 5 / 15 mins): 0.57 / 0.53 / 0.40
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-202412:16 PM10/21/2024 12:16:0026.60.08CPU Load (1 / 5 / 15 mins): 0.48 / 0.51 / 0.45
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-202412:21 PM10/21/2024 12:21:0025.503.05CPU Load (1 / 5 / 15 mins): 0.52 / 0.51 / 0.46
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-202412:29 PM10/21/2024 12:29:0022.800.08CPU Load (1 / 5 / 15 mins): 0.52 / 0.53 / 0.50
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-20242:02 PM10/21/2024 14:02:006.220.08CPU Load (1 / 5 / 15 mins): 0.56 / 0.52 / 0.51
LTE B2 (1850 – 1910 UL / 1930 – 1990 DL)
10-21-20242:27 PM10/21/2024 14:27:005.093.26CPU Load (1 / 5 / 15 mins): 0.47 / 0.52 / 0.50
LTE B2 (1850 – 1910 UL / 1930 – 1990 DL)
10-21-20242:35 PM10/21/2024 14:35:0025.800.08rebooted modem CPU Load (1 / 5 / 15 mins): 1.05 / 0.54 / 0.22
LTE B5 (824 – 849 UL / 869 – 894 DL)
10-21-20242:36 PM10/21/2024 14:36:0024.1013.60CPU Load (1 / 5 / 15 mins): 1.01 / 0.66 / 0.29
LTE B5 (824 – 849 UL / 869 – 894 DL)

Other notes:

We are using the measurement lab speed test

Any guidance on things to try would be helpful.

Thanks!
2
Thank you for contacting us. We would like to clarify a few points:

1.CPU Usage Irrelevant: We confirm that changes in CPU usage are unrelated to the frequency band switching, so there is no need for concern.

2.Reason for Switching: The device may automatically switch frequency bands due to signal strength, base station management strategies, network load, or other environmental factors. Specifically, when the signal quality of band 5 declines, the device attempts to connect to other bands.

3.Recommendation: To help you avoid automatic switching, we recommend that you lock to band 5. At the same time, please send the relevant logs to the following email: jixing@inhand.com.cn, including the Log File and System Diagnosing Data for both band 5 and band 2. Once we receive the logs, I will be able to provide you with further support.

Thank you for your understanding and cooperation. If you have any other questions, please feel free to contact us.

3
Dear Customer,

This is Victor from Inhand tech support team.

How many devices experienced this issue? Could you share us the Serial Number? 

It would be helpful if you could provide some logs with us.

Please log in the management page and go to Network=>Cellular, enable Debug:

Then go to Status=>Log, click Download Log File and Download System Diagnosing Data:

Best regards,
Victor
4
Thanks Victor and jixing for your help.

We only have 1x IR302 and it is currently at a remote site. I log in periodically to run the speed test and record results.

The S/N of the IR302 is RF302245388768

I
have enabled debugging in the cellular settings menu and will wait for a
while to capture the switch between towers. I will pull the log files
once that happens.

As I've gathered more
data I agree that the CPU usage does not seem to correlate to the poor
speeds, although if 1 is 100% CPU usage that seems like that may be a
concern, especially because  it seems to be staying at that level for a
long time?

I think I figured out the reported 0.08 upload speed issue:

It
appears that if I switch away from the tab in which the speed test is
running it will give erroneous results (low upload speed). Maybe this
has to do with how chrome handles tab resource allocation? My process
has been to start the speed test, switch to the IR302 web GUI tab and
copy the tower info and CPU usage info, record that, then switch back to
the speed test to see the finished results. It is possible that every
time I rebooted the modem I also kept the speed test tab as the active tab.

With all that said I think there is one main issue we would like to resolve:


The modem will select a weaker tower for some reason (maybe the
stronger tower dropped out for a bit), but it takes a long time before
it will switch back to the stronger tower, unless I reboot the modem
manually, then it will chose the strong tower right away as it boots up.


There are actually 2 strong bands: 5 and
14, so I really just want to exclude band 2 for now. I will try locking
to those two bands and see what happens.

Thanks again!
5
Hi there,

the serial number you provided, RF302245388768, is missing a digit. Could you please take a picture of the serial number on the device or capture a screenshot from the front-end interface?

For your reference, here’s an example of how the serial number should appear on the front-end interface:
content.png460×328 39.5 KB

Thank you for your assistance!
6
jixing,

Sorry about the incorrect serial number. It is RF3022425388769



7
Also, since band locking to LTE 5 and 14 the modem has stayed on band 5 and had great performance (25 down, 10-ish up)