Thank you for your considerable response,
Earlier i was unable to understand properly the topic being discussed.
I think the answer will be as:
possible
For examples if the global bit rate is 40Gbit/ and a QPSK modulation (2 bits per symbol), the symbol rate will
be 20Gsym/s. In both cases there are a total of 128 sub-carriers available such that:
OFDM symbol period = Symbol period * 128 = 128/(Symbol rate) = 2 * 128 /Global bit
rate.