Architecture and Performance Analysis of Lossless FFT in OFDM Systems
The design of fast Fourier transform (FFT) architecture is one of the bottlenecks in the implementation of OFDM systems. With the recent progress on the development of lossless transform, its possible applications in communication systems have received more and more attention. In this paper, a lossless integer FFT (IntFFT) architecture based on radix-22 FFT algorithm is analyzed and implemented. By exploring the symmetric property, the overall memory usage is reduced by 27.4% for a 64-point FFT design. The variance of quantization loss for both IntFFT and conventional fixed-point FFT (FxpFFT) is derived. The signal to quantization loss ratio (SQNR) and the bit error rate (BER) performance in system level is also simulated to test the accuracy of IntFFT. Based on the simulation results, IntFFT can yield comparative performance while using less memory usage than FxpFFT designs