DC subcarrier is the subcarrier whose frequency is equal to the RF centre frequency of the transmitting station.It corresponds to frequency zero (Direct Current) if the FFT signal is not modulated.DC subcarrier has no information sent on it, i.e DC subcarrier is not transmitted, but is counted in the number of subcarriers. It is used by the mobile device to locate the center of the OFDM frequency band.
In the frequency domain, the PSS and SSS occupy the central six RBs. The synchronization sequences use 62 subcarriers in total, with 31 subcarriers mapped on each side of the DC subcarrier. Five subcarriers at each extremity of the six central RBs are unused.
