So right off the bat... without seeing everything I asked for... it looks like your AP's having issues with noise. Are you seeing approx. the same uplink bandwidth on every client? What sort of speeds are you seeing on the downlink? ALSO... super silly question, but I have to ask... are you using QoS and if so have you tried turning OFF QoS (on both the AP and a sample client) and doing a speed test?
Here's something to try...
If you take one of the clients with the best modulations and SnR's... for instance, the client near the top of the list you posted that has an SnR of 34/34 and is negoting at MCS 15/11, and you clear the counters on the client's Monitor - Performance Tab, and then immediatly run a speed test to that client... what speed test results do you get, and secondly what are the majority of downlink and uplink packets percentige-wise ending up at?
Second... do the same for a client with really bad SnR and modulation... like the client, again, near the top that has an SnR of 27/26, and negotiating at MCS 12/3... do the same, on the client, clear the Monitor - Performance Tab, run a speed test... what speed test results do you get, and secondly what are the majority of downlink and uplink packets percentige-wise ending up at?
As far as a remedy... you could try the following:
- On the AP, increase your 'Subscriber Module Target Receive Level' to -50 or -55dBm
- Move to a different channel by using an SA or ACS to determine a cleaner channel
- If you're not using frequency reuse, change to flexible frames
- Reduce your channel width from 20MHz down to 10MHz
- On clients having the most uplink issues, try forcing the client to use the sector for uplink instead of the BSA, run some tests and see if it makes a difference