New low-complexity and robust time synchronization technique for optical IMDD OFDM transmissions

Area of Science:

• Optical Communications
• Signal Processing

Background:

• Orthogonal Frequency Division Multiplexing (OFDM) is used in radio, but its application in optical IMDD systems requires robust time synchronization.
• Conventional preamble-based synchronization methods face challenges in optical OFDM due to signal characteristics like chromatic dispersion.

Purpose of the Study:

• To analyze the performance of existing time synchronization techniques for optical IMDD OFDM.
• To propose a novel preamble structure and a two-stage synchronization algorithm for improved performance.

Main Methods:

• A new preamble structure designed to avoid minor peaks in coarse synchronization.
• A two-stage synchronization algorithm enabling coarse and fine synchronization without prior preamble waveform knowledge.
• Numerical simulations to evaluate performance against conventional methods.

Main Results:

• The proposed method demonstrates superior performance in terms of timing offset variance compared to conventional techniques.
• Reduced receiver complexity is achieved with the novel approach.
• The technique ensures quasi-optimal transmission capacity in unamplified transmissions, even with short cyclic prefixes.

Conclusions:

• The novel preamble and synchronization algorithm significantly enhance time synchronization for optical IMDD OFDM.
• The proposed method offers a robust and efficient solution for optical communication systems.
• It provides a practical approach for achieving high transmission capacity and reliability.