We apply the intra-symbol frequency domain averaging (ISFA) channel estimation algorithm to the intensity modulation and direct detection (IM/DD) 16QAM orthogonal frequency division multiplexing (OFDM) system and improve the performance of the system. In the paper, the weighting coefficients in the algorithm are changed to obtain the best system performance. In order to study the applicability of the algorithm, the number of different subcarriers is simulated and better system performance is obtained. In the case of changing the transmission distance, we compare the performance of traditional algorithms and ISFA.
This paper focuses on the quarter-wave plate design based on subwavelength high-index-contrast grating (HCG). The relationship among the equivalent refractive index of the HCG, the duty cycle of grating and the incident wavelength was obtained with the theory of effective medium and rigorous coupled wave analysis. By selecting the parameters and using the iterative algorithm proposed in this paper, quarter-wave plates with excellent performance can be obtained.
We proposed a new RF-pilot based carrier frequency offset and phase noise estimation (RB-CFOPNE) scheme in offset-QAM-based filterbank multicarrier (FBMC-OQAM) systems. The performance of the proposed RB-CFOPNE with rectangular QAM modulations is evaluated by Monte Carlo simulation. The results of numerical analysis show that this method could tolerant huge frequency offset and phase noise with high speed communication system. The better performance makes it become possible for real application.
KEYWORDS: Orthogonal frequency division multiplexing, Interference (communication), Phase shift keying, Radio optics, Detection and tracking algorithms, Modulation, Receivers, Optical engineering, Digital signal processing, Error analysis
A low-complexity optical phase noise mitigation scheme, based on a radio frequency pilot (RFP) and partition phase correction (PPC), is proposed. For diverse channel configurations, an optimized RFP with fixed parameters is first employed in coarse phase tracking for generality purposes. Based on the reliable predecision results, we propose a noniterative PPC algorithm to further suppress the residual noise. Numerical simulations demonstrate that compared with other phase noise compensation algorithms, the proposed scheme has better robustness and lower computational complexity. In addition, the performance degradation caused by decision errors is also discussed, and a moderate partition length with small floating range can guarantee satisfactory correction quality.