Thread Subject: 802.11a RF receiver

I am using Matlab 7.0 and trying to change the 802.11a simulink model
provided by adding a RF receiver as demonstrated on Mathworks
Webinar. However, I am having a great difficulty with the RF input
port. I can't figure out what the sample time should be. I thought it
is just 1/Bandwidth or 1/20M. Can anyone help me on this issue? Any
help will be appreciated.

Thanks