Optimization of Hopping DFT for FS-FBMC Receivers

Abstract

Filter Bank Multi-Carrier (FBMC) modulation is a promising modulation technique that is expected to play an important role in future 5G systems alongside Orthogonal Frequency Division Multiplexing (OFDM). In spite of its attractive properties, mainly the signal is well localized in frequency and time, a major drawback to FBMC is the high signal processing load compared with OFDM. Although FBMC using PolyPhase Network (PPN) requires lower computational complexity compared with Frequency Spreading (FS) implementations, FS-FBMC receivers have shown better performance compared with PPN-FBMC, especially when equalization is also considered. In this paper, we focus on reducing the complexity of FS-FBMC receivers by applying Hopping Discrete Fourier Transform (HDFT) instead of Fast Fourier Transform (FFT). Furthermore, we derive an improved HDFT based on the split radix method and analyze the resulting structure in terms of computational complexity. We show that the proposed HDFT based FS-FBMC receiver has a lower complexity and introduces a smaller delay in processing time compared to the conventional FFT based FS-FBMC receiver.