Simple full-range carrier frequency offset estimation for high speed CO-OFDM

Abstract

We propose a simple, full-range carrier frequency offset (CFO) algorithm for coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. By applying the Chinese remainder theorem (CRT) to training symbol of single frequency, the proposed CFO algorithm has wide range with shorter training symbol. We numerically and experimentally demonstrate the performance of CRT-based algorithms in a 16-ary quadrature amplitude modulation (QAM) CO-OFDM system. The results show that the estimation range of the CRT-based algorithm is full-range corresponding to the sampling frequency. Also, the bit error ratio (BER) degradation of the proposed algorithm with one training symbol is negligible. These results indicate that the proposed algorithm can be used as a wide range CFO estimator with an increased data rate in high speed CO-OFDM systems.

Adaptive time synchronization and frequency offset estimation for CO-OFDM

“…6, for all considered methods the MSEE increases with the transmission distance. Schmidl's method is more accurate than Minn's method in FO estimation because of the longer sample interval [11]. However, in comparison to the traditional Schmidl's and Minn's methods, the proposed method with pre-EDC offers the lowest value of FO estimation error.…”

Novel Phase and CFO Estimation DSP for Photonics-Based Sub-Thz Communication

“…Figure 6 shows the frame format and the structures of the transmitter and the receiver DSP. A frame started with a preamble, which was inserted to provide a wide and accurate CFO estimation [13] and the length of preambles was 576 with a sample interval of 288. After a preamble was attached, 3,840 training symbols were attached to train a channel equalizer in the receiver DSP and followed by a data sequence with a length of 34,560 symbols.…”

“…However, it is difficult for a blind phase estimator in an M-QAM system to recover a wide range of CFO. Thus, CFO estimation using a predefined preamble can be adopted to estimate CFO accurately for a wide range [13].…”

Frequency Synchronization Based on a Cascading Cross‐Correlation Function for CO‐FBMC‐OQAM

“…Despite being attractive, FBMC-OQAM is heavily subject to Carrier frequency offset (CFO), due to the orthogonality loss among the subcarriers [11,12] . Moreover, the orthogonality condition in FBMC-OQAM is imposed only in the real field.…”