On Hardware Implementation of Multiuser Multiplexing for SC-FDMA

A simple algorithmic scheme is proposed which calculates multiple variable-length FFTs/IFFTs at once by a single fixed-length one. The algorithm exploits the fact that the transform of a periodic signal is a line spectrum, the linearity property of FFT/IFFT and the shift theorem. The overall algorithm complexity is higher than calculating separate variable-length transforms, but the ease of implementation makes the scheme well-suited for FPGA based rapid prototyping systems. Because in SC-FDMA systems multiple variable-length transforms are needed for different users, the algorithm can be used to implement multiuser multiplexing. The scheme can be applied to DFT/IDFT as well as FFT/IFFT implementations.