For the case of MC-DS-CDMA where OFDM is used as the modulation scheme, the data symbols on the individual subcarriers are spread in time by multiplying the chips on a PN code by the data symbol on the subcarrier. For example, assume the PN code chips consist of {1, −1} and the data symbol on the subcarrier is −"j". The symbol being modulated onto that carrier, for symbols 0 and 1, will be −"j" for symbol 0 and +"j" for symbol 1.