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.
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.
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.
A novel orthogonal modulation scheme combining frequency shift keying (FSK) for label at 2.5 Gb/s and pulse position modulation (PPM) for payload at 40 Gb/s is proposed in this paper. The transmission performance and some influencing factors of the modulation scheme are demonstrated by simulation. The results show that this modulation scheme can increase the balanced extinction ratio (ER) and decrease the influence of the deviation of balanced ER on the transmission performance, comparing with the traditional FSK-amplitude shift keying (ASK) orthogonal modulation scheme. In addition, this modulation scheme can apply a LiNbO<sub>3</sub> Mach-Zehnder modulator to realize the FSK label erasure without additional optical sources.
We propose an orthogonal modulation scheme with 40 Gb/s Manchester-coded (MC) payload and 2.5 Gb/s frequency-shift keying (FSK) label. The high-speed FSK label is generated by an FSK modulator, which consists of two modulators, while MC payload is generated by an intensity modulator. Simulation results show that the available extinction ratio of FSK and amplitude-shift keying with MC payload can improve from 5.1 to 11.2 dB, compared with the traditional not-return-to-zero payload. The receiver sensitivities of both MC payload and FSK label show a remarkable improvement.