Blind Frequency Offset Estimation Method Based on Maximum Likelihood Two-Dimensional Search

Abstract

The invention discloses a blind frequency offset estimation method based on maximum likelihood two-dimension search. The method comprises the steps that a received signal matrix is obtained according to signal information received by a communication receiver; a frequency offset search list and a code parameter search list are initialized; frequency offset compensation signal matrixes are obtained according to a frequency offset search list compensation received signal matrix; according to the code parameter search list, the frequency offset-code parameter maximum likelihood function value of each frequency offset compensation signal matrix is calculated; the frequency offset corresponding to the maximum value in the frequency offset-code parameter maximum likelihood function values is judged. According to the blind frequency offset estimation method based on maximum likelihood two-dimension search, due to the fact that group merging processing is conducted on received signals, the result of the frequency offset-code parameter maximum likelihood function is independent of the data starting position, good estimation performance is provided for non-integrality data, and therefore the frequency offset estimation method has certain tolerance for synchronous errors.

Description

technical field [0001] The invention belongs to the technical field of communication, relates to MIMO-STBC technology of multiple-input multiple-output space-time block coding, and further relates to a blind frequency offset estimation method based on maximum likelihood two-dimensional search. The present invention can be used for blind frequency offset estimation of MIMO-STBC signals in the scene of blind identification of communication signals. Background technique [0002] The next-generation wireless communication system will provide higher transmission rate and service quality. In the context of tight spectrum resources, MIMO-STBC technology can provide technical support for the realization of this goal. In the scenario of blind recognition of communication signals, it is necessary to perform blind estimation and recognition of non-cooperative communication signals, and blind frequency offset estimation is one of the key technologies for blind signal recognition. [00...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the overhead of the training sequence leads to a reduction in spectrum utilization, and it cannot be applied to the blind recognition of communication signals.

[0005] Document 2[Shahbazpanahi S, Gershman A B, Giannakis G B. Joint blind channelland carrier frequency offset estimation in orthogonally space-time blockcoded MIMOsystems[C] / / Signal Processing Advances in Wireless Communications, 2005 IEEE 6th Workshop on.IEEE, 2005: -367] and literature [3 Shahbazpanahi S, GershmanA B, Giannakis G B. Blind and semiblind channel and carrier frequency-offset estimation in orthogonally space-time block coded MIMO systems [J]. Signal Processing, IEEE Transactions on, 2008, 56 (2 ):702-711.] The proposed blind frequency offset estimation algorithm based on OSTBC coding uses the orthogonality of OSTBC coding matrix to construct the likelihood function to complete the frequency offset estimation. This algorithm does not need training sequences or pilots, but uses OSTBC The frequency offset estimation is performed on the coded data part, the spectrum utilization rate is high, and the estimation accuracy is higher than that of the general blind frequency offset estimation algorithm, but it cannot be effectively used for quasi-orthogonal and non-orthogonal space-time block coded MIMO systems. Partial estimate, limited range of application

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