Hello,
for acceptable VoIP quality, according to ITU G.114 you should have:
- less than 150 ms one way delay
- less than 30 ms jitter
- less than 0.5% packet loss.
This can or can not work in a wireless environment.
In your case one way delay should not be an issue.
The issues are, that you might have packet loss problems because of bad link quality (caused by interference, bad antenna design, etc.) or too much traffic, etc.
A starting point in your hardware decision process can be "Cisco IOS Software Configuration Guide for Cisco Aironet Access Points" and the chapter "Configuring QoS" at
http://www.cisco.com/en/US/products/hw/wireless/ps4570/products_configuration_guide_chapter09186a0080184a9d.html
Hope this helps! Please rate all posts.
Regards, Martin