how to set the CFO standard deviation in CFO models

I need some help with a simple thing. I am trying to simulate carrier frequency offset model for Bluetooth Low Energy standard in GNURadio (I am bit new to this). For this purpose, there is a CFO model already available in it details of which are available here https://wiki.gnuradio.org/index.php/CFO_Model . I need to correctly parameterize the model with some values according to some of the knowns about the standard   

 

 

Channel Bandwidth	2	MHz
Frequency (f)	2.4	GHz
Maximum crystal Oscilator inaccuracy  (ppm)	20.8	ppm	dictated by standard
Maximum CFO bound (f*ppm/10^6)	49920	Hz	over a packet
Sample rate ( R )	4	MHz	2*BW. I assume
Sample duration (1/R)	0.00000025	s
CFO standard deviation (Hz per sample)	?

 

Can you please check if parameter values are correct. How can I determine the CFO standard deviation (Hz per sample) as described in the above link in this case?

Regards,

Yuxuan