In OFDM, the waveform can be generated by using an inverse fast Fourier transform (IFFT), e.g k is the subcarrier index and n the time index. bk is the complex symbols modulated onto subcarrier k....

In OFDM, the waveform can be generated by using an inverse fast Fourier transform (IFFT), e.g

k is the subcarrier index and n the time index. bk is the complex symbols modulated onto subcarrier k. Assume the symbol period to be NTs where Ts is the sample period. What is the subcarrier spacing? What is the frequency of the kth subcarrier?