Realization of single FFT scheme for STBC-OFDM system on FPGA

Space-time block codes are considered as one of the prominent technologies for spatial diversity which is widely used to improve wireless system performance. However, an OFDM system with space-time block codes needs multiple fast Fourier transforms (FFT) posing an adverse effect on system computational load as the number of antennas and sub-carriers grows. Therefore, in this paper we employ a single FFT scheme for the implementation of multiple transceivers on field programmable gate array (FPGA). The results showed that the hardware complexity is significantly reduced. In the case of two transmitters and two receivers, the number of logic elements and registers are reduced by about 47%, the memory is reduced by about 16%, and the number of multipliers is reduced by 50%.