What you need is more APs running at lower poer levels to cover smaller areas, spread out around the room.

lots of other trix. some of which i have seen are o pull the asians off on to one or more channel 14 aps (but that's old 11b days). o set the aps low so the wetware attenuates but i am not an expert; i just try to work with folk who are and get the hell out of their way and see that they are well supplied with coffee, food, and beer. randy