After upgrading three 5508's (which support 150 AP's) from WLC/WCS version 6.0.182.0 to version 7.0.98.0, our users complained about low signal strength. Our pre-upgrade RSSI benchmarks confirmed a decrease of -10dB to -20dB signal strength across all AP's, effectively causing wireless networking to be unusable in key areas.
After confirming our Global signal strength settings in WCS and WLC's were still at the same settings they were at prior to upgrading, we contacted our VAR for advice.
He suggested that perhaps the upgrade caused all AP's to run at a lower signal strength. He was right.
At his recommendation, we reconfigured the WCS to set two AP's to use Individual mode instead of Global mode. This is found in Radios/802.11b/g/n/Tx Power Level Assignment. Setting them to level 2 resulted in an average -15dB increase of RSSI, solving our problems in the test environment. In one case we saw an increase of -30 dB for one AP.
The signal strength loss due to the upgrade was not expected, based on the upgrade documentation. Now we must change the settings manually on the remaining 148 AP's.
I'd like to hear from anyone else who has experienced a decrease in signal strength after upgrading to Clean Air 7. If you have information from Cisco that documents this problem, I'd REALLY like to read it.
Hoping this may help you,
RS
