Consultation on Roaming Optimization for WIFI6

[xiaorenwu]

Hello everyone.

I am currently using WLC5520-8.10.196 and AP9115AXI in the office. I have noticed that some clients occasionally roam to farther APs. These clients are all Intel's WIFI6 network cards. The frequency band of AP is 80MHz.The AP3800 series used in another office area did not experience such extreme situations。

[jmanzanera]

Thanks for clarification
I was confused
According with your comments the CAT9115 is vertically hung were the 3800 is suspended ceiling. It will be important to know how they are placed , if you have a diagram it will be super helpful. As example is your CAT9115 mounted vertically with cisco logo facing opossite the 3800 or facing 3800? 

On the other hand, can you please share the nearest AP the Ap radio power level for 802.11a  band for the affected SSID? Also if you have an android phone, I recommend to install WIFI-MAN application (free option) and to the following (if you have a MAC it can be done with the wifi performance option):

- Connect the Android phone to the 3800.
- Move to CAT9115 and see how the client is seeing the enviornment and when the client decides to move. The Android device is small device with small antenna so, your laptop should be better.

As a note if you reduce the channel band to 40MH you will have more power on the AP , that means more signal with the same TPC.
I think we need to see your issue under RF perspective 

Finally I had the same issue with the Intel-based AX2xx cards and my solution was to disable the 802.11AX from the card itself (in case your issue is urgent).

[xiaorenwu]

Thank you for your reply. Here is the layout diagram. APs are all attached to the wall facing the office, and most computers are equipped with WIFI6 network cards. For example, some people's computers may be located under AP3, but they may roam to AP5. Because my computer has been upgraded, I have also simultaneously upgraded to WIFI6 and increased it to 80MHz. I am using a WIFI5 network card myself, which is also near AP3, so the probability of this kind of roaming occurring is very low.

[Leo Laohoo]

How big is this room? 

What is the the wireless NIC driver?

[xiaorenwu]

Thank you for your answer. Approximately 630 square meters, using Intel (R) Wi Fi 6E AX211 160MHz network card

[Leo Laohoo]

---

@xiaorenwu wrote:
using Intel (R) Wi Fi 6E AX211 160MHz network card

---

I've asked this question before and have not received a definitive answer other than "I'll check again, thank you".  So what is the wireless NIC driver(s) version used? 

---

@xiaorenwu wrote:
Approximately 630 square meters

---

Provide the dimension of the room.

[xiaorenwu]

Thank you for your response,

1.Updated to the latest driver version 23.80.1, but occasional issues still occur

2.

[Leo Laohoo]

Way too many APs.  

For a 30 x 20, I can get away with two APs.  Max.

[jmanzanera]

Hello 
Thanks for the information.
According with the diagram it seems you are in an openspace probably we will have some cell overlap and high interference between the APs as you are using 80MHz channel with (not sure your location and your regulatory domains).

I'm guessing your cell diagram will looks as follows

As you are experience this issue with WIFI6 and only certain clients and after seeing your TPC configuration , I recommend to reduce the cells a little bit as follows (I personally don't like to use TPC max at 30 - maybe you need to create a different RF profile):

- Reduce 30Max to 17 dBm
- Confirm with the client affected client how the client is seeing the environment - probably will be good to use netspot tool or something like this (if you have ekahaw it will be great).

- Are you using Loadbalancing between the APs? If yes, please remove it.
- Are you using dual band? If yes, please try to remove 2.4 if not needed.
I think the problem is located more on the client side that on the wireless configuration. If you want to influence the client to remain on a certain AP , try to reduce the cells 

[xiaorenwu]

Yes, as circled in your picture, the WLAN is not configured with load balancing. Basically, 2.4 is turned off. Regarding the modification of the maximum TPC value, we will also try to create a new RF for experimentation. Thank you!

[JPavonM]

As previously adviced, I would recommend you to lower the maximum TX Power to match half that on the client side. (https://fccid.io/PD9AX211D2L)

From your picture, it seems to me that the optimal coverage is provided from AP6 as its radiation pattern extend to the center of the room.

By the way, have you ever heard about polarization and the need to match that in both ends? As a wireless expert, you need to avod installing APs in such way that their polarization is vertical to the clients. Why you are not using L-shaped wall mounts?

[xiaorenwu]

We are currently trying to reduce the transmission power of individual APs. Due to the fact that the network cable layout in the room existed several years ago, the placement of APs was not well considered. This experience has been a good accumulation. thank you!