FBMC/OQAM Modulators with Half Complexity
The Filter Bank MultiCarrier (FMBC) concept can be seen as an extension of the Orthogonal Frequency Division Multiplex (OFDM) principle. Indeed, in the case where each sub-carrier uses an Offset Quadrature Amplitude Modulation (OQAM), the authors get with the FBMC/OQAM system a multicarrier modulation scheme with relaxed orthogonality constraints so that, differently from OFDM, a Cyclic Prefix (CP) is no longer required. However, the OQAM principle, that permits to separately handle the real and imaginary parts of the complex QAM symbols, presents an implementation drawback. Indeed, compared to OFDM at the same bit rate, the Inverse Fast Fourier Transform (IFFT) has to run twice faster.