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Fastmile 5G 5G-24WA Rev02 BAD52 Firmware Bug - WiFi Channel Selection

Hello Optus,

I've returned from holidays and turned my Fastmile 5G back on only to discover that my wifi devices can't maintain a stable connection to the Nokia. Doesn't matter whether it's my laptop, iPhone, Android Phone, Google Home etc. The WiFi radio on the device seems to switch off for a few seconds several times an hour disconnecting all my devices.

This lead me to survey my environment with inSSIDER to examine congestion and then to try and select the radio channel's used by your Nokia modem.  I was previously using the Auto Algorithms provided in the GUI but it seems to seek to the most congested radio channels which doesn't make any sense. So I sought to change this to a fix channel. This is when I discovered that I can change the channel and bandwidth settings in the GUI but the radio on the device does not honour the settings in the GUI. Sometimes the radio stays on the same channel, sometimes it changes to a completely different channel, sometimes it changes to the channel I select.  Why? 

See these screen captures.

I would appreciate a firmware fix so I can have Home WiFi. In the meantime, can you please advise the combinations of channel numbers and bandwidth on the 2.4 and 5 GHz bands that can be sucessfully set via the modem GUI.

Examples

My network is called Balmoral. Nokia modem auto channel setting chooses the most congested channels. Why?

Why does the auto channel algorithm choose a channel swamped by Telstra Air and my neighbour when other channels are largely clear?Why does the auto channel algorithm choose a channel swamped by Telstra Air and my neighbour when other channels are largely clear?

I set the 5GHz channel to 52 and saved. Wifi channel switched from 150 to 36...

WifiChannelBug.JPG

 

Thank you 

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Contributor
Contributor

Re: Fastmile 5G 5G-24WA Rev02 BAD52 Firmware Bug - MuMimo

Hello Optus,

Can you advise whether the device has MuMimo capability? When attempting to set it on or off in the GUI the log file records an error.

2021-01-12 22:05:13 err - [wlan_config_web_app.cgi] MuMimoEnable=0

2021-01-12 22:06:18 err - [wlan_config_web_app.cgi] MuMimoEnable=1

 

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Moderator
Moderator

Re: Fastmile 5G 5G-24WA Rev02 BAD52 Firmware Bug - MuMimo

Hey @sysdmin. In regards to getting the best information and advice on this matter, I recommend getting in touch with our dedicated 5G Technical Support Team via 1300 101 693, as they will be able to assist further from there (Mon - Fri: 8am - 8pm and Sat: 9am - 5pm) 

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Super Contributor
Super Contributor

Re: Fastmile 5G 5G-24WA Rev02 BAD52 Firmware Bug - MuMimo

Hi - Your modem may be OK. If you are concerned about the error, maybe a power restart will remove it. The Nokia Fastmile Datasheet states it has MU-MIMO which applies to the 802.11ac 5Ghz band only, so 2.4Ghz is SU-MIMO.

You have 10 other 2.4Ghz SSIDs visible near to your home, with 3 of these with signal power readings of -55 dBm to -60 dBm which can potentially compete with your modem's 2.4Ghz radio  for airtime causing interference or slow performance in that band. Interesting that you can see 8 Telstra Air SSIDs broadcasting but apart from one FON SSID which is using Channel 11, same as yours, they do not appear on the list of routers - they may be too far away to cause any issues - readings of 90 dBm are at the very edge of potential marginal coverage.

I take it you have programmed as many devices that are capable to connect to the 5Ghz band. I have found on Apple devices, it is the device that chooses the band, even after you set it for 5GHz and the 2.4Ghz SSID is also pre-registered in the phone or iPad , if you move to another location in home, if it thinks the signal is going to be better on the 2.4Ghz, it switch over to it. I leave my modem's channel selection to Auto and let the modem decide.

If you can't avoid using 2.4Ghz, setting the channel bandwidth to 20 Mhz rather than 20/40 you may achieve more stability as you will only use one Channel per connection in SU-MIMO queuing. In the 2.4 Ghz band, there are only 13 x 5Mhz wide channels available, but only three of these are non-overlapping channels - Ch 1, 6 and 11 - meaning they are the best ones for usage. Most routers choose these as preferred in default and then will use whatever grouping of 4x5 Mhz bandwidth (for 20 Mhz) are available to them. If you allow 40 Mhz, the modem can use use 8x5 Mhz bandwidth or 2 channels leaving only one for other devices - in your photo ABB, BigPond and Brie Modems are using 2 Channels - note they are separated by 4x5Mhz bandwidth.

In 5 Ghz there are many more non-overlapping channels available with wider bandwidth accommodation, so leaving settings on Auto 20/40/80 is OK as the modem will allocate as it sees fit - if you set it for 80 Mhz only , you will occupy three of the available channels. In 5Ghz, there are three groups of frequencies - low (Ch 36-48), medium (52-64 and 100-140) and high (149-165). The medium ones are called DFS - these are reserved for Defence and Civil Airlines but can be used by routers if the router does not sense any radar detections. If it does, it must remove itself from that band and move the device to a non DFS channel - DFS means a lot of monitoring load is placed on the modem's CPU, so routers may prefer to use those frequencies as a last resort.

That may be why the Nokia preferred you didn't set Channel 52 permanently and vectored you to the high and then low frequency area. In the photo Balmoral was using two DFS channels 106 and 112 which may OK for some time and the Nokia may have a preference to moving devices from those frequencies when others become available to lessen its monitoring responsibilities. Its a very dynamic environment , so that is why I like to leave modems decide what is best for them to use. 

Backgrounder on DFS Channels and 802.11ac Channel allocation principles. 

https://www.smallnetbuilder.com/basics/wireless-basics/33082-smallnetbuilder-s-wi-fi-dynamic-frequen...

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