Burst Transmission Symbol Synchronization in the Presence of Cycle Slip Arising from Different Clock Frequencies

TL;DR

This paper presents a novel two-step algorithm employing the Gardner Detector to detect and correct cycle slips caused by clock frequency mismatches, improving symbol synchronization and reducing bit error rates in burst communication systems.

Contribution

It introduces a new feed-forward synchronization method that estimates and corrects cycle slips and timing drifts, avoiding stability issues of feedback schemes.

Findings

Effective cycle slip detection and correction demonstrated

Significant BER improvements shown in simulations

Algorithm compensates large symbol rate offsets

Abstract

In digital communication systems different clock frequencies of transmitter and receiver usually is translated into cycle slips. Receivers might experience different sampling frequencies from transmitter due to manufacturing imperfection, Doppler Effect introduced by channel or wrong estimation of symbol rate. Timing synchronization in presence of cycle slip for a burst sequence of received information, leads to severe degradation in system performance that represents as shortening or prolonging of bit stream. Therefor the necessity of prior detection and elimination of cycle slip is unavoidable. Accordingly, the main idea introduced in this paper is to employ the Gardner Detector (GAD) not only to recover a fixed timing offset, its output is also processed in a way such that timing drifts can be estimated and corrected. Deriving a two steps algorithm, eliminates the cycle slips arising from wrong estimation of symbol rate firstly, and then iteratively synchronize symbol timing of a burst received signal by applying GAD to a feed forward structure with the additional benefits that convergence and stability problems are avoided, as they are typical for feedback schemes normally used by GAD. The proposed algorithm is able to compensate considerable symbol rate offsets at the receiver side. Considerable results in terms of BER confirm the algorithm proficiency.