my client was having a legacy wireless network in a warehouse environment with ceiling height about 10m high , the legacy AP was 1242 with external antenna where the signal coverage was good and never reported coverage problems, however after replacing it with the new 2802E with Omnidirectional antenna AIR-ANT2544V4M , the customer starts to report some coverage holes and poor coverage issues
the RSSI in some locations are -75 or even worse while AP power level is 3, so I am wondering why the coverage issues were never notified with the legacy APs, the second point why the WLC is not setting much higher power levels to the AP if some poor coverages might be detected , shall I configured power level manually or not recommended ?
When you mention 1242 with external antenna, are you referring to Omni? I assume we just swap out the 1242 with the 2802? Was a wireless site survey and design completed before the replacement of the AP's? if not it should have been performed and a design completed to determine suitable locations for the 2802 AP models given they will have a different antenna radiation patterns for both bands compared to EOL 1242 AP's.
Issues can arise if AP's are using Omni Antennas at high mounting locations (10m ) as the distance between each AP may be closer together than the distance to the clients on the floor, (not taking into account any affect from signal attenuation from shelves etc) so RRM( TPC) may adjust power to account for this, leading to issue with client connectivity.
I would suggest perform a wireless site survey based on the least capable device used in the location to determine, current coverage issues and remediate if at all possible.
95% of the time I use directional antennas with warehouse to ensure the signal is where I want it.
The problem with rrm is that it has no way of knowing that the APs are 10m above client level. So with Omni directional antenna the APs will be hearing their neighbours way above client level and making their decisions based on that.
You can change the minimum tx level allowed by adjusting the figure in 802.11a / 802.11bg -> TPC
Or if you are using RF profiles do it per profile.
I have never done a single warehouse deploent regardless of antenna where you can get away with leaving RRM in its default state.