Tuning "roaming"

[Ed W]

Hi, am I missing, or are there any plans to add some variables to tune 
the roaming sensitivity? (ie the wpa_supplicant roaming, card is a 
RT2870 usb)

We have some customers in mobile configuration and whilst all is ok in 
the lab, out in the field we seem to find that it's fairly easy to see 
reasonable sized swings in signal strength which in turn causes regular 
roaming jumps and interruption in service.  In fact several customers 
say they are literally bouncing between access points every 30/120 
seconds when using a config such as:
     bgscan="learn:30:-64:120"

The mobile customers are actually on yachts and I think because of the 
very subtle movement of the boat tilting, plus sometimes shadows due to 
small physical obstructions that will be drifting in/out of the way, the 
effect is fairly large implied changes in signal level

What might be helpful would be to have a frequent scan interval, but 
only roam if we have recorded an average signal strength over multiple 
periods which is greater than some trigger threshold. Probably someone 
smarter than me knows why this won't work, so just kicking around an idea?

Thanks

Ed W