Beamflex causing roaming problems with warehouse devices

[jeff_roback]

We’re having a really tough time getting 25 R610’s working in a warehouse environment with Vocollect (Honeywell) T5 devices that are used by the warehouse personnel. After a lot of investigation, review of logs, and packet captures it appears that the issue is around the T5 devices misreading the signal strength of the AP’s and staying on ap’s with poor coverage. The T5 devices are deigned to be used by operators that are driving forklifts around a warehouse so they are extremely sensitive to changes in the RF environment, always looking for a better ap.
Unfortunately they are using the AP beacons to read signal strength, so even if they are connected to an AP with great coverage, when they see a beacon from that ap with a weak signal, so when they see a beacon from an AP that physically does have good coverage but shows as having a weak signal, they assume the operator has moved from that AP and they imediately scan and jump to another ap. This process seems to repeat over and over again, resulting in a terrible experience for the client devices. These T5 devices do use older 802.11 b/g radios, and the newer devices like ipads, iphones, androids and laptops work great. Unfortunately the T5 devices are mission critical so I need a way to get them working reliably. Before Ruckus was in place, the warehouse was using Ubiquity access points, which worked great for the t5’s, just not for anything else... So we’re kind of stuck now... overall it seems like both the Ruckus and the T5 devices are trying to independently solve the same problem but they’re conflicting with each other resulting in terrible device experience. We’ve tried just about every configuration change possible including adjusting signal strength up and down, changes to power management mode on the devices, forcing b, forcing g, bss minrate, smartroam, changing roam thresholds on the device, etc.... but nothing seems to get the devices to believe the rucks signal is as strong as it actually iis because the beacons show lower strength. Does anyone have any experience with client devices that are using beacons to identify signal strength, and have any strategies to prevent them from getting confused by beamflex? Vocollect/Honeywell has asked if we can turn off beamflex, but it seems like that’s built in to the hardware and not changable. I have opened a case with Ruckus tech support but haven’t been able to get past the “Just reboot It” stage... I don’t think they understand we have a fundamental problem with the interaction of the devices and beamflex. Thanks for any thoughts....

[andrew_somervil]

Are you 100% sure it is Beamflex? The maximum possible Beamflex gain on an R610 is only 6dB. I'm surprised that is sufficient to cause dramatic roaming issues. In any case since I assume all the APs are set to the same power level then the beacons from the 'correct' AP should still be stronger than the beacons from all other APs so why does the client device roam to a weaker signal AP?

[michael_brado]

That's a very good question, why the T5 roams to a weaker signal AP...?
Does the scanner manufacturer have an answer/patch to this fundamental
problem?

My suggestion is to reduce the tx power on AP 2.4g radios.  Do not reduce
bss-minrate on 2.4g, which would cause the AP to ignore a T5 that was still
trying to connect/roam from too far away, but lowering the AP 2.4g power
would prevent the T5s from seeing them from too far away.

Beamflex is an advantage, sending client power only in the direction of each
client, and thus less interference to other clients on the same AP.

[tom_pisacic]

Hello,

we have similar problem as mentioned above. we have a warehouse with metal high racking around 40ft high and Ruckus 7782 omni are installed at the ceiling.  Racking is full of frozen food on pallets.We have tried almost everything possible, from smart-roaming, min data rate, load/band balancing, manual channels, manually set a tx power but still are experiencing issues.
I've been using the Ekahau Site Survey with Side Kick and the signal does not look that bad, SNR does not go lower then 20.. In most areas, SNR is above 25. 
Clients are Citadel RF devices with rubber duck antenna 3dBi 2.4GHz but thinking to switch over to dual band antennas. The app what our operators use, is a web based app which does not refresh until been clicked within the app.

What else can you suggest me to try? Do we have proper APs installed in this kind of environment? Do we need to switch out our APs 7782 omni and go for newer type of AP with directional antennas? Is there anything what I can do to improve with the current setup?

thanks!

[michael_brado]

Hi Tom,
   
Warehouses can be challenging environements for mobile scanner devices, up and down the racks, and forklift drivers with wi-fi, etc. 
You might benefit from adding an AP or two at different ends of different aisles, to radiate down the rows in addition to the ceiling mounted APs.