Make sure you are using antenna diversity (dual antennas on the AP, mobile client, or both). This will counteract a condition known as multipath (reflected signals reaching the AP or mobile client at the same time but out of phase). If you only have one antenna on the AP and on the mobile client, then this is most likely the cause for your poor signal quality.
When you say the site survey has poor quality of signal, I'm assuming that you are referring to the signal quality reading in the site survey utility. With the Cisco utility, the signal quality meter is a depiction of the signal to noise ratio. If you are getting a low signal quality, it usually means that some type of interference exists.
You may need to have a spectrum analysis performed to see if there is some level of interference in the 2.4GHz band.
Multipath can be part of the problem. However, if you are seeing this low signal quality throughout the facility, it is unlikely that multipath is the cause. The effect of multipath is variable depending on the three dimensional positioning of the sending and receiving antenna. In this case, the AP antenna is likely stationery but the client device is not. Since the client device is moving, the multipath effect would not be consistent.
It is still not a bad idea to utilize antenna diversity, though. You will see some benefit even if you are not experiencing any adverse effects of multipath. The Cisco APs evaluate the quality of the signal for each client uniquely. Based on the quality, the AP chooses which antenna to use to transmit to each client. This is somewhat different from what some of the other vendors do with antenna diversity. Most others always transmit on the primary antenna, but will receive on both.
All of the suggestions by the responders are excellent please be sure to do them. If after all you still have problems then you should consider that at some point minor electrical damage may have happened to the RF Mod. in the AP that would affect the receiver sensitivity; in that case you would see poor signal quality with good signal strength...it does happen. But I would certainly try all of the other suggestions before determining this to be the problem.
IntroductionHow to use the Wireless LAN Controller Configuration Analyzer (WLCCA)
Javier Contreras is a Senior Tech Lead for the Wireless Business Unit in Cisco, with over 2 decades of experi...
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(#)For this reason being that : - application that doesn't use multicast, sends one copy of each packet ( data unit of traffic at layer 3 ) to each client (" who seeks the traffic ).- application that does use multicast, sends ...
Transferring Crash file from standby:
Login to the Active WLC in HA.
(Cisco Controller) >transfer upload datatype crash
(Cisco Controller) >transfer upload filename <Desired filename>
(Cisco Controller) >transfer up...