Satellite-ground link-oriented frequency offset interference elimination method
A technology of frequency offset interference and satellite-ground link, which is applied in the field of satellite communication, can solve the problems of increasing the complexity of EM algorithm implementation, etc., and achieve the effects of improving joint tracking performance, improving detection accuracy, reducing complexity and processing delay
Inactive Publication Date: 2022-01-28
XIAN INT UNIV
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Problems solved by technology
For the elimination of joint channel and frequency offset interference, in the early literature, Lee J H et al. used the algorithm EM (Expectation Maximization, expectation maximization algorithm) to improve the algorithm elimination performance through repeated iterations of carrier frequency offset and channel parameters, but the EM algorithm is All parameters need to be updated during iteration, thus increasing the implementation complexity of the EM algorithm
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[0058] The invention will be further described below in conjunction with the accompanying drawings and specific implementation examples.
[0059] For scenarios with complex channel conditions such as low-orbit satellite services such as cities, signal interference not only comes from carrier frequency offset, but also includes signal frequency selective fading introduced by multipath channels. Therefore, user signal detection under the condition of channel and frequency offset mixed interference is also a key problem faced by the downlink of the LEO satellite system. For the joint elimination of channel and frequency offset interference, in the early literature, ML algorithm was widely used as a classic joint channel and frequency offset interference elimination algorithm. However, when the estimator statistics of the received signal are complex and there are many parameters to be estimated, the performance of the algorithm is not ideal. Related studies use the EM algorithm t...
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The invention provides a satellite-ground link-oriented frequency offset interference elimination method, which is characterized in that frequency offset pre-estimation and elimination of a frequency domain are adopted, so that the combined tracking performance of the frequency offset and the channel of frequency domain processing is improved; and after a signal with frequency offset interference is transformed into a frequency domain through discrete Fourier transform (DFT), coarse estimation and elimination of frequency offset are carried out in the frequency domain, then an estimated frequency offset value is fed back to a time domain, when the frequency offset interference is small, the signal after coarse elimination can meet communication requirements, however, when multipath fading of a channel is serious and frequency offset interference is large, combined tracking is carried out on frequency domain frequency offset and the channel, so that complexity and processing time delay of a low earth orbit satellite algorithm are reduced, and the purpose of improving user signal detection precision is achieved through combined channel and frequency offset interference elimination.
Description
technical field [0001] The invention relates to the technical field of satellite communication, in particular to a frequency offset interference elimination method for satellite-ground links. Background technique [0002] Due to the limited resources on the satellite, if too many training sequences are used, the signal transmission efficiency and frequency band utilization will be seriously reduced; therefore, it is necessary to perform blind detection of user signals based on the statistical characteristics of received signals. Aiming at the signal blind detection algorithm, Y.Sato et al. improved the minimum mean square error function, and proposed the concept of self-elimination blind signal detection algorithm for the first time. A subspace blind algorithm is proposed, which needs to obtain the correlation spectral density of the channel, and the channel delay is less than half of the number of subcarriers; the algorithm can be completed in an OFDM (Orthogonal Frequency ...
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CPCG01S19/37
Inventor关庆阳吴双
OwnerXIAN INT UNIV