Novel Blind Recognition Algorithm of Frame Synchronization Words Based on Soft-Decision in Digital Communication Systems

Jiangyi Qin,Chunwu Liu,Jing Zhou,Zhiping Huang,Shaojing Su,Zhaohong Deng

doi:10.1371/journal.pone.0132114

Abstract

A novel blind recognition algorithm of frame synchronization words is proposed to recognize the frame synchronization words parameters in digital communication systems. In this paper, a blind recognition method of frame synchronization words based on the hard-decision is deduced in detail. And the standards of parameter recognition are given. Comparing with the blind recognition based on the hard-decision, utilizing the soft-decision can improve the accuracy of blind recognition. Therefore, combining with the characteristics of Quadrature Phase Shift Keying (QPSK) signal, an improved blind recognition algorithm based on the soft-decision is proposed. Meanwhile, the improved algorithm can be extended to other signal modulation forms. Then, the complete blind recognition steps of the hard-decision algorithm and the soft-decision algorithm are given in detail. Finally, the simulation results show that both the hard-decision algorithm and the soft-decision algorithm can recognize the parameters of frame synchronization words blindly. What’s more, the improved algorithm can enhance the accuracy of blind recognition obviously.

Highlights

In the digital communication system, frame synchronization is the foundation for the followup signal processing, such as forward error correction (FEC) and information access
The Quadrature Phase Shift Keying (QPSK) signal is used to verify the blind recognition algorithm and the simulations results show that soft-decision is better than the hard-decision
Simulations are used to verify the validity of the frame synchronization words blind recognition algorithms proposed in section 2 and section 3

Summary

Introduction

In the digital communication system, frame synchronization is the foundation for the followup signal processing, such as forward error correction (FEC) and information access. Frame synchronization words can mark the place for mapping receiving binary stream and eliminating redundant information. The frame synchronization words parameters are different across the various communication systems. In background of the non-cooperation communication system, the blind recognition of frame synchronization words is necessary for obtaining the information contained in the unknown binary signal [1,2,3,4]. Comparing with conventional hard-decision, soft-decision utilizes the confidence level of each receiving data to recognize parameters [5,6,7,8,9]. The QPSK signal is used to verify the blind recognition algorithm and the simulations results show that soft-decision is better than the hard-decision

Methods

Results

Conclusion