Real-time reception of NHS-OFDM signal with SPA-enhanced channel estimation for intensity-modulated direct-detection systems
Gang Chen, Ming Chen, Wen Chen, Lede Yin, Aitao Deng, Yuxin Cai, Dengqiao Wang · Chinese Optics Letters · 2022
In this Letter, we have experimentally verified a low-complexity subcarrier pairwise-averaging (SPA)-enhanced channel estimation (CE) method for small-size fast Fourier transform (FFT) non-Hermitian symmetric orthogonal frequency-division multiplexing (NHS-OFDM) transceivers.Compared with intra-symbol frequency averaging (ISFA), more than 20% look-up tables and 10% logic power consumption can be saved.The least-square (LS), ISFA, and SPA CE methods are compared by offline and real-time digital signal processing approaches.The results show that the receiver sensitivity of the SPA NHS-OFDM transmission system with 64/128-point FFT can be improved by more than 1 dB at the bit error rate of 3.8 × 10 -3 compared to the LS.