ofdm in simulink

Hi everyone

i have this ofdm generator that i created in SIMULINK.

parameters :

bernoulli binary generator : sample time : 1e-12 sec. samples per frame : 524288 [524288x1]

4 QAM Modulator : gives a matrix of : [262144x1]

Reshape : convert to 2-d matrix of [512x512]

my question is :

i want to know ( after the ifft block ) which kind of OFDM signal i got and how much sub carriers it has ?? (all i know is i got bandwidth of 450MHZ)

IMAGE OF THE GENERATOR IS ATTACHED :

http://imageshack.us/photo/my-images/402/questionw.jpg

any help will be appriciated ! thanks