Front-back synchronous code joint frequency estimation method
A preamble and frequency estimation technology, which is applied in the field of satellite communication, can solve the problems of complex implementation, poor algorithm frequency estimation performance, and complicated calculation process, etc., and achieve the effect of simple implementation, accurate estimation of frequency deviation, and high frequency deviation accuracy
Active Publication Date: 2020-11-24
成都链讯信息技术有限公司
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[0005] The M&M algorithm has a large deviation correction range and a relatively low threshold of about 0dB. The implementation process is relatively complicated and is suitable for rough estimation of frequency offset. To work under SNR, if you need to work under medium and low SNR, you need to accumulate the signal first and then perform Kay algorithm, which requires a large number of known symbols and high requirements for burst structure; Fitz algorithm and L&R algorithm The range of deviation correction is small, the performance of the algorithm is not much different and there is no obvious limit, it is only suitable for fine frequency estimation, but as the signal-to-noise ratio decreases, the root mean square error performance of the algorithm deviates more and more from the Cramereau boundary, And it is necessary to perform correlation calculations, which is more complicated to realize
[0006] To sum up, the existing algorithms need a large number of continuous known symbols when doing frequency fine estimation. The more known symbols, the better the frequency estimation performance and the more complicated the calculation process; for continuous known For a burst with a small number of symbols, the performance of the existing algorithm for fine frequency estimation is poor, and the calculation is more complicated
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[0018] The present invention will be further described below in conjunction with accompanying drawing:
[0019] as attached figure 1 A typical schematic diagram of the burst structure shown, the front and reverse link bursts in the MF-TDMA satellite communication system adopt the general burst structure of linear modulation, and there are several user payloads of one or more bursts in each burst segment, and the other segments are known symbols such as preamble and postamble. A preamble is usually present in each burst, at the front end of a burst, and a postamble may be present.
[0020] as attached figure 2 As shown, the method for joint frequency estimation of pre-post asynchronous codes of the present invention comprises the following steps:
[0021] S1: Let the known symbol of the preamble be q k , the received preamble symbol is q' k , for q k Conjugate of , L is the number of preamble symbols, calculate the center symbol angle of the preamble Where arg is the...
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The invention discloses a front and back synchronous code joint frequency estimation method, which adopts phase deviation of two sections of known symbols (a front synchronous code and a back synchronous code) with a distance to inversely deduce frequency deviation. The method comprises the following steps of: calculating a central symbol angle of the front synchronous code; calculating a centralsymbol angle of the rear synchronous code; and calculating frequency deviations. The method is easy to implement, the frequency deviation within a small range can be estimated accurately only with a small number of known symbols, and the frequency estimation performance of the method is far higher than that of other algorithms using the same number of known symbols.
Description
technical field [0001] The invention relates to the technical field of satellite communication, in particular to a method for accurately estimating the frequency of bursts with pre- and post-synchronization codes. Background technique [0002] In the satellite communication system of the MF-TDMA system, the system transmits information according to the TDMA mechanism, with burst as the smallest unit. Due to the frequency deviation and Doppler frequency shift between the transceiver devices, there is a certain frequency deviation in the received baseband signal, which seriously affects the signal receiving performance. Therefore, whether the frequency offset can be quickly and correctly estimated and calibrated is the premise of receiving data correctly, and it is an indispensable step in the satellite communication system. [0003] In the MF-TDMA system, when the system completes the acquisition synchronization, the system corrects the time and frequency of receiving other ...
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Login to View More IPC IPC(8): H04L27/26
CPCH04L27/266
Inventor 朱南丁伟姜彬
Owner 成都链讯信息技术有限公司