Design is critical to avoid sticky clients. There are protocols for roaming, but in the end the client normally controls how it will roam. Some vendors allow you to disassociate a client below a certain RSSI threshold, but I haven’t had much success with that strategy.

I disable lower data rates and adjust power levels to maintain correct overlap between APs cells (approximately 20% overlap between cells at your lowest data rate). The lower data rates have longer effective transmission distances and can result in sticky clients. In residential I normally make 24 Mbps mandatory and disable everything below. I leave all higher data rates as supported. Then I start tuning power levels and can re-enable data rates, if necessary (I would re-enable a data rate if the coverage is poor at full power). I move in reverse, trying to maintain the highest data rate possible. If you don’t have good coverage unless using 1.5 Mbps and full power, you need to re-evaluate your design.

Also make sure you do not have overlapping adjacent channels. This more difficult on 2.4 than 5 as there are only 3 non-overlapping channels (1, 6, and 11). 5 GHz does not carry as well as 2.4 GHz through walls and will likely have different power requirements. There are products that will measure the RF environment and dynamically set channel and power levels (Cisco CleanAir, for example).

This link is for 2.4 GHz channel planning, but the principles are applicable to 5 GHz, as well.

[Link: blog.aerohive.com]