WiFi Scan: Signal Strength jumps between two values with more than 10dB difference

[NM10]

Hi,

I observe quite strange behavior, when peforming wifi scan.  I trigger an active scan every 30 sec (with iw dev wlp0s20f3 scan), and log the results. For the same AP/SSID/BSSID I get either -47dBm or -62dBm, and the reported values actually alternate.  The whole setup is however static, nothing is moving, and the reported RSSI of the active connection (iw dev wlp0s20f3 link) actually remains constant. Only values reported from scan are changing.

Would be great to find an explanation and hopefully fix it!

Here are some details about the setup:

18.04.1-Ubuntu

5.4.0-131-generic

Network controller: Intel Corporation Device 9df0 (rev 30)
Subsystem: Intel Corporation Device 0034
Kernel driver in use: iwlwifi
Kernel modules: iwlwifi

description: Wireless interface
product: Intel Corporation
vendor: Intel Corporation
physical id: 14.3
bus info: pci@0000:00:14.3
logical name: wlp0s20f3
version: 30
serial: 94:e6:f7:e7:ef:e1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=iwlwifi driverversion=5.4.0-131-generic firmware=46.6bf1df06.0 ip=10.0.87.245 latency=0 link=yes multicast=yes wireless=IEEE 802.11
resources: iomemory:400-3ff irq:16 memory:404ac10000-404ac13fff

[Jocelyn_Intel]

Hello, @NM10. 

Thank you for posting on the Intel® communities. I will gladly assist you here. 

Please, answer these questions to have a better perspective of this issue: 

1. What is the issue this is causing specifically (low performance, connectivity issues, etc.)? 
2. What is the model of your Intel wi-fi card? 
3. Is it a desktop or a laptop? 
4. Is the Intel Wi-Fi card the pre-installed wi-fi card in your motherboard or is it an integration (upgrade/ not the original card in the laptop/motherboard)? 
5. Was it working fine before? 
6. Make sure that your wireless adapter is connected properly by running # lspci command in the terminal and verifying if the wireless adapter is recognized. This is an example of what should display. 
7. Make sure that the module is installed properly running # modinfo iwlwifi command. This is an example of the output.   
8. Type # lsmod | grep iwlwifi to make sure the driver is loaded, the output should be like this, If the result is empty, the driver hasn't been loaded. Most likely to be a distribution issue: 
9. Type # dmesg | grep iwlwifi. If the result is empty, the driver wasn’t initialized and this is a distribution issue: 
10. Type the # dmesg | grep “no suitable firmware found!” command, the result is not empty, that means that you don't have a suitable FW, you need to check here for supported FW or here for the latest versions. 

Best regards,  

Jocelyn M.   

Intel Customer Support Technician. 

[NM10]

Hi,

Thanks for the first reply. I observe the issue on multiple PCs with Intel WiFi Modules integrated via M2 interface.

One of them is Intel NUC8i7BEH. The iwlwifi driver is loaded. Wifi communication works, but the roaming is not optimal, and I assume scanning issues.  Would be great to understand the behaviour.

BR,

[NM10]

Hi,

Thanks for the first reply. I observe the issue on multiple PCs with Intel WiFi Modules integrated via M2 interface.

One of them is Intel NUC8i7BEH. The iwlwifi driver is loaded. Wifi communication works, but the roaming is not optimal, and I assume scanning issues.  Would be great to understand the behaviour.

BR,

[Jocelyn_Intel]

Hello, @NM10. 

Thank you for your information, however, I am still missing information. 

1. So, the problem is the roaming but, can you specify how it is not optimal? 
2. What is the model of your wi-fi card? 
3. Just to confirm, are those integrations (upgrades/ Wi-fi cards you installed)? 
4. Were they working fine before with the original/preinstalled wi-fi cards?  

Best regards,  

Jocelyn M.   

Intel Customer Support Technician. 

[Jocelyn_Intel]

Hello, @NM10.   

We are checking this thread and we would like to know if you were able to review our previous post. If you need further assistance, please do not hesitate to contact us back. 

Best regards,  

Jocelyn M.   

Intel Customer Support Technician. 

[Jocelyn_Intel]

Hello, @NM10.   

We have not heard back from you so we will proceed to close this thread now. If you need any additional information, please submit a new question as this thread will no longer be monitored.  

Best regards,  

Jocelyn M.   

Intel Customer Support Technician.