Currently I'm working on a issue which is very stubborn.
One of our customers has very large open areas that are being made of aluminium walls , floors and ceiling and. Next to the room itself there is a lot of metal in the area / machinery , desks etc. These are confined area's.
Clients have connectivity issues. What we've done this far :
- when enabling lower data rates (12 - 18Mbps) so effectively enabling QPSK connection seems to be more stable.
- When using patch antenne's it seems to be meer stable. (AP's are typically mounted against the ceiling).
- Mounted AP 30CM below ALU ceiling --> no difference.
- (long) Guard interval does not change anything.
- Started using 20Mhz channels to have less CCI.
- Disabling some AP's to not have to many AP's.
- Test with AP with integrated antenna in the area, some issues. You'll see a connection drop in MCS rate when you move away (only a few meters) from the test AP
- Multiple site surveys have been conducted (using Ekahau by multiple parties) to check for interferers , Rogue's , Coverage etc, all fine.
- issue occurs in both bands but most clients typically connect to 5Ghz.
Typically when a client is moving away from an AP you'll see that the connection drops to MCS 1 - 4. Also the clients are very sticky in this highly reflective area's. Effectively this leads to situations that a client does not roam to a neighboring AP whilst it has a very crappy connection (MCS1).
When we had not enabled 12 - 18 Mbps in many cases clients could not connect.
WLC reports in many cases a very good RSSI / SNR eventhough the client device thinks otherwise.
In similar smaller areas it works as a charm. In warehouse / office all works fine except these environments. We tried with 8.5 and 8.10 code / 3800 series AP's.
As mentioned using patch antenne's it seems to be more stable, we get less complaints but the throughput is still very low because of the MCS shifting.
Has anyone some other suggestions ?