|wanderer is correct. Your problem has nothing to do with what frequency your equipment is operating at.|
What is mainly causing you to lose connections is the number of people attempting to connect to any single wireless access point.
While our enterprise level wireless project is on hold (3'd year running now due to budgetary issues) we're using SOHO level equipment to provide an in-house "guest" type wireless access (internet only, no internal access).
I've found on more than one occasion when too many users are attempting to connect to a specific access point this starts an ongoing session of dropped clients.
Lets say the maximum number of clients a single access point can handle is 12. Along comes another user who attempts to connect to the same access point. Because the AP is all ready fully saturated, it has to drop one existing user in order to accept the new user. Now user 1 who just got bumped reconnects and bumps someone else and this goes on and on until the number of requests drops below the saturation threshold of the device. If you have 10, 15 or 20 extra users all attempting to connect at the same time to a saturated AP, well, I suspect you get the drift.
If you can't reduce the number of wireless users, you will have to increase the number of available access points. Even a WDS system has similar limitations. Adding AP's only works up to a point as well..
I think you really need to rethink your setup. 90+ wireless clients is an awful lot for one area. Don't you have any network cables pulled into the rooms? If you do, all possible clients should always be on a wired connection. This will reduce the total number of wireless clients and give them better network performance. On a head-to-head comparison, wireless can't even come close to wired for performance because aside from being inherently insecure, wireless is always very susceptible to lag and latency. Personally, you couldn't give me a wireless connection to use when I can possibly have a wired one.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.