Evaluation of Symbol Timing Recovery Algorithms in a High-Speed Fiber-Optic Communication System

Abstract

In high speed fiber optical communication system, symbol synchronization plays a key role. The received signal with timing offset will degrade the performance of symbol synchronization. It is, therefore, important to estimate this timing offset and perform synchronization based on the estimation. Symbol synchronization can be performed by feedforward and feedback algorithms. In this thesis Maximum likelihood, Oerder and Meyr, Gardner symbol timing recovery(STR)algorithms are evaluated for fiber optic communiciation system. Three master thesis students are involved in this project. Ai Yun developed STR algorithms, Evaluation of STR were performed by Pavithra Muralidharan and Hardware implementation by Tauseef Ahmad. This thesis report describes the evaluation of STR algorithm in detail. A test bench set up was developed in MATLAB to model optical communication system, and this set up was used for evaluation. Modeled channel impairments were used to analyze their effect on symbol timing recovery. Alongside an estimate of chromatic dispersion filters are also provided. Though performance differences of the three algorithms were marginal, when they are modified for hardware, it was found that Gardner will be an area efficient algorithm and Oerder and Meyr algorithm will be efficient in terms of power. As a result of this evaluation and hardware implementation Oerder and Meyr algorithm is a better choice in terms of area, power and performance.