Avoiding Aeroscout RFID Location Misdetection in Multi-Floor

[jackson.ku]

Hi,

I have a customer with multi-floor building. They deployed Cisco WLC 5508 and Access Point 1142, also deployed Location-Based Services ( MSE, Aeroscout mobile view ). We have readed "Wi-Fi Location-Based Services—Design and Deployment Considerations" guide and do our best to consider the placement of access point, but rfid tag misdetection in multi-floor still occured.

Please help to advise how to avoid rfid misdetction in multi-floor? Can I configure the WCS or Aeroscout Mobileview and limit the specific rfid tag only locate at one floor ( if we make sure the rfid tag never move to other floor )?

Best Regards,

Jackson

[Scott Fella]

I don't believe there is a configuration to do that. The hard part with location is bleed from adjacent floors. So are the APs stacked above and or below each other? Do you have a lot of RF bleed and did you tweak the RF? By this, I mean did you adjust the data rates and power for the APs. You might be able to tweak the RF enough, but it will not be 100% accurate for location. This is why it's had to implement e911 based on location due to the phone associated to an AP in an adjacent floor.

The other thing is... Did you perform the calibration on Aeroscout? That helps a lot. I have a customer that has license for 6000 tags and has 3.5 mil sq ft and after doing the calibration they can say its almost 100%. The calibration is a requirement for Aeroscout.

Sent from Cisco Technical Support iPad App

[dhurshowy]

Location is based on UL from the client to the APs so I would not think adjusting power or data rates on the APs would make any difference. (Hmm this is true for WiFi clients, is it still true for RFIDs? I would think so)

Basically just try to make sure that more (and at stronger signals) APs hear you from the floor you're on rather than the floor you're not on. If you have APs on multiple floors, I would think that stacking them so the second floor AP is directly above the first floor AP would make the first floor more accurate as you should never (I guess it depends how different the walls are between floors) see a 2nd floor AP stronger than it's first floor equivalent.

If you do not want to track anything on the second floor then remove the second floor map from the building in NCS. If this is applicable for only specific RFIDs then I do not know how you would do it.

[dhurshowy]

(Info from Cisco TAC. As noted, these should not be changed without TAC support)

Configuration Changes for Greater Location Accuracy

In some RF environments, where location accuracy is around 60 to 70% or where incorrect client or tag floor location map placements occur, you might need to modify the moment RSSI thresholds in the aes-config.xml file in the opt/locserver/conf/ directory of the mobility services engine (CSCsw17583).

The following RSSI parameters might require modification are:

•locp-individual-rssi-change-threshold

•locp-aggregated-rssi-change-threshold

•locp-many-new-rssi-threshold-in-percent

•locp-many-missing-rssi-threshold-in-percent

From the release notes for the MSE above, referencing the following bug:

CSCsw17583  Location wrongly reported on different floor occassionally

Symptom

The location of a device is wrongly reported on a different floor (upper, lower or same level floor but on a different building) or the location flip flops between different floors.

Conditions:

Depends on the RF environment of the deployment.

But have been seen in areas with:

1. Low inter floor separation

2. Presence of shafts or open areas which leak the RF to other floors or other buildings.

3. Presence of metal and other objects which may affect the signal strength.

4. Example classic case: AP was located close to an elevator and reported different RSSIs for a stationary client based on the movement of the elevator up and down.

Workaround:

If you are running the most recent software release on the code branch and still seeing wrong location tracking such as wrong floor or building then the problem is most probably linked to the Wireless deployment, the AP layout, or the Configuration of WCS.

There are few parameters that can be changed on the Location Appliance and MSE to enhance this, however, prior to proposing any software changes Cisco TAC needs to understand your deployment and what is causing the wrong location tracking. Please contact TAC through a service request.

So the default values should not be changed unless you are having problems with location accuracy as described above. We would have to do a detailed analysis of the location issues and run some debugging sessions to determine the issue before changing any values.