How drive BLDC/Permanent magnet motor with sensor less driving with sinusoidal method?

hello everyone 

i want to understand and drive BLDC/Permanent magnet motor  with sensor less driving with sinusoidal method.I know bldc trapezoidal(six step ) method of driving but in my new project i have drive motor with 

sinusoidal method.

i go through some reference datasheet and some direct driver ic . but basically i didn't understand how it works? 

http://www.st.com/en/evaluation-tools/steval-ihm038v1.html

can BLDC motor drive with both (trapezoidal/sinusoidal) method ?

please help me 

Sorry for poor English

thank you