Study On Symbol Rate Estimation Algorithms Of Communication Signals

This paper is focusing on a study of the symbol rate estimation of digital communication signals. Symbol rate is one of the most important parameters in the digital communication systems. Especially in the non-cooperative communications, the accurate estimation of symbol rate is of great importance.In this paper, firstly, the basic concept, principles and classification as well as the development trend of symbol rate estimation are introduced. Then the currently most frequently used algorithms are analyzed and discussed, while emphasis is laid on several blind algorithms of Intermediate Frequency (IF) signals.Subsequently, a novel blind symbol rate estimation algorithm for CPFSK signals is proposed based on combination of Discrete Wavelet Transform (DWT) with Continuous Wavelet Transform (CWT). CWT is used for the extraction of detailed information of the signal obtained from the DWT, and greatly reduces the influence of the noise. Thus the proposed algorithm can achieve an improved accuracy at low SNR.A blind symbol rate estimator based on the wavelet multi-resolution analysis is proposed. The orthogonal multi-resolution wavelet decomposition is performed for the received signals and the symbol rate can be estimated via the spectrum of the correlation function of the detailed coefficients at different stages. The performance of the proposed algorithm is less influenced by the parameters of the received signals, such as modulation type and carrier frequency, thus is very suitable for the estimation before modulation identification.Detailed experimental results with regard to various simulated signals as well as practical signals are provided which have proved the feasibility and effectiveness of the above two algorithms.