CN112436880B - Doppler power spectrum modeling method and device under multi-communication scene - Google Patents

Doppler power spectrum modeling method and device under multi-communication scene Download PDF

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CN112436880B
CN112436880B CN202011110247.0A CN202011110247A CN112436880B CN 112436880 B CN112436880 B CN 112436880B CN 202011110247 A CN202011110247 A CN 202011110247A CN 112436880 B CN112436880 B CN 112436880B
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power spectrum
doppler power
fingerprint
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scene
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CN112436880A (en
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邓中亮
刘雯
郑奭轩
林文亮
王珂
刘浩
于晓艺
刘洋
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Beijing University of Posts and Telecommunications
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1851—Systems using a satellite or space-based relay
    • H04B7/18519—Operations control, administration or maintenance
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/185—Space-based or airborne stations; Stations for satellite systems
    • H04B7/1853—Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
    • H04B7/18539—Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
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Abstract

The embodiment of the invention provides a Doppler power spectrum modeling method and device under a multi-communication scene, wherein a Doppler power spectrum model of a low-orbit satellite channel under the multi-communication scene is obtained by acquiring Doppler power spectrum actual measurement data according to each communication scene based on the multi-communication scene. Moreover, the shape of the Doppler power spectrum can reflect the characteristics of Doppler effect and multipath fading in the channel of the low-orbit satellite, so that the accuracy of Doppler power spectrum model fitting to an actual scene can be improved by mapping the actually measured Doppler power spectrum data; moreover, the actual measurement data of the doppler power spectrum of multiple communication scenes are different, and for each scene, reference data related to each scene, namely the actual measurement data of the doppler power spectrum corresponding to the reference fingerprint of each communication scene, is used, so that the doppler power spectrum model is fitted to each actual scene.

Description

Doppler power spectrum modeling method and device under multi-communication scene
Technical Field
The invention relates to the technical field of low-earth-orbit satellite communication, in particular to a Doppler power spectrum modeling method and device in a multi-communication scene.
Background
In communication, channel modeling is an abstract way to model channels and classify them according to their mathematical characteristics of input/output signals and the mathematical characteristics of the relationships between input/output signals. The doppler power spectrum is an important parameter in channel modeling, can reflect information such as channel doppler frequency offset, multipath fading, fading dynamics, and the like, and is an important reference basis in communication system design. Therefore, currently, for a wireless channel in a channel, doppler power spectrum models commonly used in wireless channel modeling, such as Jakes, Gaussian, Flat, and the like, are used.
A Low Earth Orbit (LEO) satellite (LOS for short) has a fast operation speed, so that a Low Earth Orbit (Low Earth Orbit, LEO for short) satellite channel has characteristics of large doppler frequency shift, high propagation attenuation, dominant Line of Sight (LOS) signal component, and the like, which may cause the shape of a doppler power spectrum to be inconsistent with the conventional doppler power spectrum model, and thus, the conventional doppler power spectrum models are not suitable for the Low Earth Orbit satellite channel, and how to establish the doppler power spectrum model more conforming to an actual scene for the Low Earth Orbit satellite channel becomes an urgent problem to be solved.
Disclosure of Invention
The embodiment of the invention aims to provide a Doppler power spectrum modeling method and device under a multi-communication scene, which are used for solving the problem of how to establish a Doppler power spectrum model which is more consistent with an actual scene for a low-earth orbit satellite channel in the prior art. The specific technical scheme is as follows:
in a first aspect, an embodiment of the present invention provides a doppler power spectrum modeling method in a multi-communication scenario, including:
acquiring Doppler power spectrum measured data of a low-earth-orbit satellite channel in each observation time under various communication scenes;
mapping the actually measured Doppler power spectrum data to determine each Doppler power spectrum map;
constructing an atlas fingerprint of each Doppler power spectrum atlas so that the channel characteristics of the low-orbit satellite correspond to the atlas fingerprint;
clustering the atlas fingerprints to determine a plurality of types of communication scenes;
selecting a reference fingerprint sample most relevant to the communication scene from fingerprint samples of each communication scene, wherein the reference fingerprint sample is a reference fingerprint under each communication scene, and a mapping relation among reference data, the reference fingerprint and the communication scene is established, and the reference data is Doppler power spectrum actual measurement data corresponding to the reference fingerprint of each communication scene and is used for fitting a Doppler power spectrum model of each communication scene;
according to the mapping relation, fitting model parameters to be fitted in a Doppler power spectrum model to be fitted in each communication scene by using reference data and reference fingerprints in each communication scene to obtain a Doppler power spectrum model of the low-earth orbit satellite channel in a multi-communication scene, wherein the Doppler power spectrum model to be fitted is the Doppler power spectrum model of the model parameters to be fitted.
Further, the acquiring doppler power spectrum measured data of the low earth orbit satellite channel in each observation time under multiple types of communication scenes includes:
under the low-orbit satellite channel multi-communication scene, measuring a satellite channel to obtain received signal data, wherein the low-orbit satellite channel multi-communication scene comprises: classifying the low-orbit satellite channel communication scenes according to different elevation angle ranges, different terminal motion states and different ground scattering environments to obtain various communication scenes;
and extracting Doppler power spectrum actual measurement data in each observation time from the time domain signal envelope of the received signal data.
Further, the constructing an atlas fingerprint of each doppler power spectrum atlas to make the channel characteristics of the low earth orbit satellite correspond to the atlas fingerprint comprises:
extracting geometrical characteristics of an atlas shape according to the corresponding relation between the atlas fingerprints and the channel characteristics of the low-orbit satellite, and constructing the atlas fingerprint of each Doppler power spectrum, wherein the atlas fingerprint comprises the geometrical characteristics, and the geometrical characteristics comprise: width mean, highest point position, kurtosis, skewness and height mean;
and establishing a mapping relation between each spectrum fingerprint and the Doppler power spectrum actual measurement data corresponding to the spectrum fingerprint.
Further, the extracting the geometric features of the atlas shape according to the corresponding relationship between the atlas fingerprint and the channel features of the low-orbit satellite, and constructing the atlas fingerprint of each doppler power spectrum atlas includes:
and extracting the geometric characteristics of the shape of the spectrogram by adopting a method based on the geometric image characteristics according to the corresponding relation between the spectrogram fingerprint and the channel characteristics of the low-orbit satellite, and calculating and generating each Doppler power spectrogram fingerprint.
Further, the correspondence between the atlas fingerprint and the channel characteristics of the low earth orbit satellite includes:
a one-to-one correspondence between a width mean in the profile fingerprint and a doppler spectrum broadening in a channel feature of the low earth orbit satellite;
the highest point position in the atlas fingerprint is respectively corresponding to the direct path frequency offset and the direct path power in the channel characteristics of the low-orbit satellite;
the kurtosis in the atlas fingerprint is respectively corresponding to fading dynamics, multipath time delay expansion and multipath number in the channel characteristics of the low-orbit satellite;
the skewness in the atlas fingerprint is respectively corresponding to the multipath number and the shadow fading degree in the channel characteristics of the low-orbit satellite;
and the height average value in the atlas fingerprint respectively corresponds to the shadow fading degree and the multipath fading size in the channel characteristics of the low-orbit satellite.
Further, the clustering the atlas fingerprint to determine a plurality of types of communication scenarios includes:
clustering the atlas fingerprints by adopting a K-Means clustering algorithm to obtain K classes of atlas fingerprint point sets;
determining the K classes as communication scenes;
selecting a reference fingerprint sample most relevant to each type of communication scene from the fingerprint samples of each type of communication scene, wherein the selection comprises the following steps:
and determining the atlas fingerprint corresponding to the centroid of each class as a plurality of reference fingerprint samples.
Further, the fitting, according to the mapping relationship, a to-be-fitted model parameter in a to-be-fitted doppler power spectrum model of each communication scene by using the reference data and the reference fingerprint in each communication scene to obtain a doppler power spectrum model of the low-earth orbit satellite channel in a multi-communication scene includes:
obtaining a Doppler power spectrum model to be fitted, wherein the Doppler power spectrum model to be fitted comprises: model parameters to be fitted, including: the method comprises the following steps of (1) carrying out left truncation frequency point, right truncation frequency point, maximum Doppler shift, Doppler shift of LOS (line of sale) path, influence factors of multipath power and influence factors of direct path power;
generating a target function by using the model parameters to be fitted;
according to the mapping relation, utilizing reference data and reference fingerprints in each communication scene to minimize the value of the target function;
and aiming at each scene, when the objective function obtains the minimum value, obtaining the value of the model parameter to be fitted, and obtaining the Doppler power spectrum model of the low-orbit satellite channel in a multi-communication scene.
Further, the doppler power spectrum model to be fitted is:
Figure GDA0003163121500000041
wherein S (f) is a predetermined Doppler power spectrum model, rect (f)l,fr) Is in the range ofl,fr]Rectangular window function of flIs a left truncated frequency point, frIs a right cut-off frequency point, alpha is an influence factor of multipath power, pi is a circumferential rate, f is frequency, fmaxFor maximum Doppler shift, β is the influence factor of the direct path power, δ (·) is the Dirichlet function, flosDoppler shift for line of sight, LOS, path;
the objective function is:
Figure GDA0003163121500000042
wherein, E (f)l,fr,fmax,flosα, β) is the objective function, Sexp(f,tn) Is tnActual measurement data of the Doppler power spectrum at a moment, wherein ^ is integral sign, d in df is infinitesimal, and S (f)l,fr,fmax,flosAnd alpha, beta) is the Doppler power spectrum model to be fitted;
for each scene, when the objective function obtains a minimum value, obtaining a value of the model parameter to be fitted to obtain a doppler power spectrum model of the low-earth orbit satellite channel in a multi-communication scene, including:
for each scene, when E (f)l,fr,fmax,flosAlpha, beta) is obtained, the model parameter to be fitted { fl,fr,fmax,flosAnd the value of alpha, beta, obtaining a Doppler power spectrum model of the low-orbit satellite channel in a multi-communication scene.
In a second aspect, an embodiment of the present invention provides a doppler power spectrogram modeling apparatus in a multi-communication scenario, including:
the acquisition module is used for acquiring Doppler power spectrum actual measurement data of the low-orbit satellite channel in each observation time under various communication scenes;
the first processing module is used for mapping the actually measured Doppler power spectrum data to determine each Doppler power spectrum map;
the construction module is used for constructing the spectrum fingerprint of each Doppler power spectrum so as to enable the channel characteristics of the low-orbit satellite to correspond to the spectrum fingerprint;
the clustering module is used for clustering the atlas fingerprints to determine a plurality of types of communication scenes;
the selection module is used for selecting a reference fingerprint sample most relevant to each type of communication scene from fingerprint samples of each type of communication scene, the reference fingerprint sample is a reference fingerprint under each type of communication scene, a mapping relation among reference data, the reference fingerprint and the communication scene is established, and the reference data is Doppler power spectrum actual measurement data corresponding to the reference fingerprint of each type of communication scene and is used for fitting a Doppler power spectrum model of each type of communication scene;
and the second processing module is used for fitting the parameters of the Doppler power spectrum model to be fitted in each communication scene by using the reference data and the reference fingerprints in each communication scene according to the mapping relation to obtain the Doppler power spectrum model of the low-orbit satellite channel in the multi-communication scene, wherein the Doppler power spectrum model to be fitted is the Doppler power spectrum model of the parameters of the model to be fitted.
In a third aspect, an embodiment of the present invention provides an electronic device, including a processor, a communication interface, a memory, and a communication bus, where the processor and the communication interface complete communication between the memory and the processor through the communication bus;
a memory for storing a computer program;
a processor for implementing the steps of the method of any one of the first aspect when executing a program stored in the memory.
The embodiment of the invention has the following beneficial effects:
according to the Doppler power spectrum modeling method and device under the multi-communication scene, provided by the embodiment of the invention, a Doppler power spectrum model of a low-orbit satellite channel under the multi-communication scene is obtained by acquiring Doppler power spectrum actual measurement data according to each communication scene based on the multi-communication scene. Moreover, the shape of the Doppler power spectrum can reflect the characteristics of Doppler effect and multipath fading in the channel of the low-orbit satellite, so that the accuracy of Doppler power spectrum model fitting to an actual scene can be improved by mapping the actually measured Doppler power spectrum data; moreover, the actual measurement data of the doppler power spectrum of multiple communication scenes are different, and for each scene, reference data related to each scene, namely the actual measurement data of the doppler power spectrum corresponding to the reference fingerprint of each communication scene, is used, so that the doppler power spectrum model is fitted to each actual scene.
Of course, not all of the advantages described above need to be achieved at the same time in the practice of any one product or method of the invention.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic flowchart of a doppler power spectrum modeling method in a multi-communication scenario according to an embodiment of the present invention;
FIG. 2 is a diagram of a LEO satellite channel Doppler power spectrum pattern according to an embodiment of the present invention;
FIG. 3 is a diagram illustrating a mapping relationship between a fingerprint and a channel characteristic according to an embodiment of the present invention;
FIG. 4 is a diagram illustrating an embodiment of a process for clustering fingerprints according to the present invention;
FIG. 5 is a schematic diagram illustrating scene labeling of clustered multi-class collections according to an embodiment of the present invention;
FIG. 6 is a diagram illustrating a mapping relationship between reference data, reference fingerprints, and a scene according to an embodiment of the present invention;
FIG. 7 is a diagram of a LEO satellite channel Doppler power spectrum model according to an embodiment of the invention;
fig. 8 is a schematic structural diagram of a doppler power spectrogram modeling apparatus in a multi-communication scenario according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
First, for the convenience of understanding the embodiments of the present invention, the following terms used in the embodiments of the present invention will be described.
The map hereinafter refers to an image or a figure for explaining an object, which is drawn from a real object and edited by classification. The atlas fingerprint is a unique atlas feature set. Clustering in the following is the process of dividing a collection of physical or abstract objects into classes composed of similar objects. The parameter fitting in the following is to solve unknown parameters in the model in the process of simulating the model law by using experiments or real data.
Based on the above description of the terms, the overall description is continued below to facilitate understanding of the doppler power spectrum modeling method and apparatus in the multi-communication scenario provided by the embodiments of the present invention.
Aiming at the doppler and fast fading characteristics of the LEO satellite channel, the inventor pays attention to the problem of doppler power spectrum modeling in the LEO satellite channel in some parameters affecting the characteristics of the communication channel, such as a power delay profile, a channel impulse response, a doppler power spectrum and the like. The doppler power spectrum has a direct influence on the fading dynamics and fading depth of the LEO satellite channel, and needs to be accurately described. Therefore, constructing the doppler power spectrum model is an important premise and basis for designing the LEO satellite communication system and verifying the performance of the key technology.
Based on the above consideration, the inventors have studied that a doppler power spectrum model is proposed based on statistical characteristics of arrival angles and fading characteristics of received signals in an azimuth plane and an elevation plane, which are caused by multipath effects and doppler effects in each scene. The constructed Doppler power spectrum model (hereinafter also referred to as a Doppler power spectrum model to be fitted) is mainly obtained by firstly establishing a geometric statistical model of a scattering environment, then calculating a channel autocorrelation function and finally performing Fourier transform on the autocorrelation function. The constructed doppler power spectrum model contains unknown parameters, and parameters of a model to be fitted in the constructed doppler power spectrum model need to be fitted and verified through actually measured doppler power spectrum data (hereinafter also referred to as actual measurement data of the doppler power spectrum) in each communication scene, so that modeling of the doppler power spectrum is completed.
For the unknown parameters (hereinafter also referred to as model parameters to be fitted) in the doppler power spectrum model, the unknown parameters are closely related to the measured doppler power spectrum data of each communication scene. Therefore, it is necessary to provide a doppler power spectrum modeling method and apparatus in a multi-communication scenario according to an embodiment of the present invention, based on a research basis that actual doppler power spectrum measurement data in the multi-communication scenario are different, and for each scenario, the actual doppler power spectrum measurement data in each communication scenario is used to fit unknown parameters of a low-orbit satellite channel in a doppler power spectrum model in each communication scenario, so that an obtained doppler power spectrum model of the low-orbit satellite channel in the multi-communication scenario is closer to each actual communication scenario. Moreover, the Doppler effect and the multipath fading characteristics in the channel of the low earth orbit satellite can be reflected based on the shape of the Doppler power spectrum, and the actually measured Doppler power spectrum data is mapped, so that the accuracy of the Doppler power spectrum model for fitting an actual scene can be improved.
The following provides a description of a doppler power spectrum modeling method in a multi-communication scenario according to an embodiment of the present invention.
The Doppler power spectrum modeling method under the multi-communication scene provided by the embodiment of the invention is applied to establishment of an LEO satellite channel model and research and development of a channel simulator.
As shown in fig. 1, a method for modeling a doppler power spectrum in a multi-communication scenario according to an embodiment of the present invention includes the following steps:
and step 110, acquiring Doppler power spectrum actual measurement data of the low-orbit satellite channel in each observation time under various communication scenes.
The observation time can be set according to the user requirement, and is used for acquiring the actual measurement data of the Doppler power spectrum within a period of time.
And 120, performing mapping on the actually measured Doppler power spectrum data to determine each Doppler power spectrum map.
Actually measured data are required to be obtained in order to complete the construction of a doppler power spectrum model of a low-earth orbit satellite channel in a multi-communication scene, namely the actually measured doppler power spectrum data refer to actually measured doppler power spectrum data of an LEO satellite channel in a multi-class actual communication scene. Wherein, the doppler power spectrum is the power distribution of the signal in the doppler domain. For clarity of layout, the communication scenario with respect to the LEO satellite channel is described hereinafter.
And 130, constructing an atlas fingerprint of each Doppler power spectrum atlas, so that the channel characteristics of the low-orbit satellite correspond to the atlas fingerprint.
And 140, clustering the atlas fingerprints to determine a plurality of types of communication scenes.
Step 150, selecting a reference fingerprint sample most relevant to each type of communication scene from the fingerprint samples of each type of communication scene, wherein the reference fingerprint sample is a reference fingerprint under each type of communication scene, and establishing a mapping relation among reference data, the reference fingerprint and the communication scene, and the reference data is measured Doppler power spectrum data corresponding to the reference fingerprint of each type of communication scene and is used for fitting a Doppler power spectrum model of each type of communication scene.
And step 160, fitting the parameters of the model to be fitted in the Doppler power spectrum model to be fitted in each communication scene by using the reference data and the reference fingerprints in each communication scene according to the mapping relation, and obtaining the Doppler power spectrum model of the low-orbit satellite channel in the multi-communication scene.
The Doppler power spectrum model to be fitted is a Doppler power spectrum model with unknown parameters such as model parameters to be fitted.
Compared with the related art, because a single communication scene is mostly considered for the doppler power spectrum model, and the Jakes power spectrum in the related art is used for describing the doppler power spectrum of the channel, the problem of dynamic change of the doppler power spectrum is not concerned, the influence of the time-varying characteristic of the low-orbit satellite channel on the doppler power spectrum cannot be accurately described, and the accuracy of the channel model is low.
In the embodiment of the invention, the Doppler power spectrum model of the low-orbit satellite channel in the multi-communication scene is obtained by acquiring Doppler power spectrum actual measurement data according to each communication scene based on the multi-communication scene. Moreover, the shape of the Doppler power spectrum can reflect the characteristics of Doppler effect and multipath fading in the channel of the low-orbit satellite, so that the accuracy of Doppler power spectrum model fitting to an actual scene can be improved by mapping the actually measured Doppler power spectrum data; moreover, the actual measurement data of the doppler power spectrum of multiple communication scenes are different, and for each scene, reference data related to each scene, namely the actual measurement data of the doppler power spectrum corresponding to the reference fingerprint of each communication scene, is used, so that the doppler power spectrum model is fitted to each actual scene.
It should be noted that, the communication scenario of the LEO satellite channel may be composed of the following two factors: firstly, because the communication elevation angle between the LEO satellite and the ground terminal changes at any moment, and the doppler frequency shift and multipath fading of channels corresponding to different elevation angles are different; secondly, the terminal will experience various ground scattering environments such as city, suburb, countryside, forest area, and expressway, and the channel multipath fading corresponding to different ground scattering environments is also different. Both the two factors can influence the Doppler power spectrum, and the communication scenes of elevation angle LEO satellite channels are continuously varied and rich, so that the LEO satellite communication scenes are divided into various communication scenes according to different elevation angle ranges, different terminal motion states and different ground scattering environments. For example, a scene is a communication elevation angle of 40 degrees, and an urban environment.
In the embodiment of the present invention, in these low-earth satellite channel multi-communication scenarios, satellite channels are measured to obtain received signal data, where the low-earth satellite channel multi-communication scenario includes: classifying the low-orbit satellite channel communication scenes according to different elevation angle ranges, different terminal motion states and different ground scattering environments to obtain various communication scenes; and extracting Doppler power spectrum actual measurement data in each observation time from the time domain signal envelope of the received signal data, wherein the Doppler power spectrum actual measurement data can be a Doppler power spectrum. Thus, sufficient received signal data is acquired by performing actual satellite channel measurement in these scenarios.
The signal source for measuring the received signal data may be an orbiting satellite or a simulated satellite platform built by using a high tower, a high building, a high mountain, an airship, a hot air balloon, a helicopter, or the like. For doppler power spectral characteristic measurements, the test case is typically a single frequency sine wave.
Because the test case is a single-frequency sine wave signal, the actual measurement data of the Doppler power spectrum can be extracted according to the following formula:
Figure GDA0003163121500000101
wherein S isexp(f,tn) For the actually measured data of the Doppler power spectrum in each observation time, exp is English abbreviation of experiment (experiment), FFT is English abbreviation of fast Fourier Transform (fast Fourier Transform), and tnIs the observation time of the nth Doppler power spectrum, i.e. the central time of the observation time window of the nth Doppler power spectrum, rn(t) is a time domain signal of the received signal data in the nth observation time window, and delta tau is the length of the observation time window, and in order to ensure the accuracy of the measured data, delta tau should not be greater than the minimum generalized stationary process duration of the received signal. Where generalized stationary is a random process that is desirably constant and the autocorrelation function is only related to the correlation interval length.
Acquired Doppler power spectrum actual measurement data Sexp(f,tn) The data is shown in fig. 2, where N is 1,2, … N, N is the serial number of the observation time window, and is the doppler power spectrum data sample volume, and each obtained doppler power spectrum sample is a curve with rapid fluctuation and dense density. Fig. 2 shows schematically: in the period of communication between the LEO satellite and the ground mobile terminal, the movement of the LEO satellite to the ground causes regular change of communication elevation angle, and multipath of the LEO satellite under the condition of different communication elevation anglesThe degree of fading and the doppler effect are different and therefore also result in a change in the doppler power spectrum. Wherein the content of the first and second substances,
Figure GDA0003163121500000111
is the angular velocity, alpha, of the satellite relative to the center of the earth1,α2,α3Respectively, are different angles of elevation for the communications,
Figure GDA0003163121500000112
respectively at alpha1,α2,α3The UE is a ground user terminal, and the DPS is a short term Doppler Power Spectrum (Doppler Power Spectrum). However, the shape characteristics of the doppler power spectrum samples have differences and unique characteristics, and the shape of the doppler power spectrum is an important basis for establishing a model of the doppler power spectrum and can reflect information such as channel doppler frequency offset and multipath fading, so that the doppler power spectrum shape characteristics are focused, and the data are mapped and stored for subsequent processing.
Secondly, it should be noted that, in order to distinguish and obtain doppler power spectrum shape characteristics in a multi-communication scene of an LEO satellite channel, establish a spectrum fingerprint, and facilitate scene classification, in the embodiment of the present invention, a spectrum fingerprint of each doppler power spectrum needs to be constructed first, so that channel characteristics of the low-orbit satellite correspond to the spectrum fingerprint, and the implementation process is as follows:
the method comprises the following steps of firstly, extracting geometrical characteristics of an atlas shape according to the corresponding relation between atlas fingerprints and channel characteristics of the low-orbit satellite, and constructing the atlas fingerprint of each Doppler power spectrum atlas, wherein the atlas fingerprint comprises the geometrical characteristics, and the geometrical characteristics comprise: width mean, peak position, kurtosis, skewness, and height mean.
Wherein, the width mean is the broadened size of the doppler spectrum, i.e. doppler spread. The height average may be an average multipath fading magnitude. The kurtosis is a statistic of curve steepness or smoothness, and is used for reflecting the fading dynamic degree and fading depth of the channel. Because the number of the multi-paths in the channel is small or the multi-paths are influenced by shadow fading, the Doppler power spectrum shape has different degrees of asymmetry, and therefore, the skewness is the measure of the symmetry degree of the curve graph.
The first step may specifically include: and extracting the geometric characteristics of the shape of the spectrogram by adopting a method based on the geometric image characteristics according to the corresponding relation between the spectrogram fingerprint and the channel characteristics of the low-orbit satellite, and calculating and generating each Doppler power spectrogram fingerprint. Referring to fig. 3, the correspondence between the map fingerprint and the channel characteristics of the low-earth satellite includes:
a one-to-one correspondence between a width mean in the profile fingerprint and a doppler spectrum broadening in a channel feature of the low earth orbit satellite;
the highest point position in the atlas fingerprint is respectively corresponding to the direct path frequency offset and the direct path power in the channel characteristics of the low-orbit satellite;
the kurtosis in the atlas fingerprint is respectively corresponding to fading dynamics, multipath time delay expansion and multipath number in the channel characteristics of the low-orbit satellite;
the skewness in the atlas fingerprint is respectively corresponding to the multipath number and the shadow fading degree in the channel characteristics of the low-orbit satellite;
and the height average value in the atlas fingerprint respectively corresponds to the shadow fading degree and the multipath fading size in the channel characteristics of the low-orbit satellite.
After each Doppler power spectrum fingerprint is generated, the Doppler power spectrum shape characteristics under multiple scenes of an LEO satellite channel can be obtained, and a spectrum fingerprint database is established, so that scene classification is facilitated. The geometric statistical features of the extracted atlas should correspond to the channel characteristics to construct the atlas fingerprint, and more importantly, the embodiment of the present invention can more fully characterize the channel characteristics by using a small number of graphic features, as shown in fig. 3. Since the atlas is a wave curve, the atlas fingerprint is made up of a set of geometric feature vectors, including the width mean μwidthHeight mean value μhightHighest point position ymaxThe kurtosis K,Skewness S, etc., the vector is mathematically represented as follows:
Figure GDA0003163121500000122
wherein the width mean value muwidthThe calculation formula is as follows:
μwidth＝xmax-xmin
in the above formula,. mu.widthIs the width of the atlas, width is the width, xmaxIs the maximum abscissa value of the map, max is the maximum, xminIs the minimum abscissa value of the map, and min is the minimum.
Height mean value muhightThe calculation formula is as follows:
Figure GDA0003163121500000121
the highest point position generally represents the LOS path, the abscissa and ordinate thereof
Figure GDA0003163121500000133
ymaxRespectively representing the frequency offset and the power of an LOS path;
in the above formula,. mu.hightIs the height mean, high is the height, N is the number of Doppler shift samples, ynThe ordinate, i.e., amplitude, of the signal at the nth doppler shift sample point.
The kurtosis K is calculated as follows:
Figure GDA0003163121500000131
wherein K is kurtosis, σ2Is ynThe variance of (c).
The skewness S is calculated as follows:
Figure GDA0003163121500000132
wherein S is skewness.
And secondly, establishing a mapping relation between each spectrum fingerprint and Doppler power spectrum actual measurement data corresponding to the spectrum fingerprint.
In the second step, for the same time, a mapping relationship is established between the doppler power spectrum fingerprint of any observation time window in the time and the doppler power spectrum empirical model corresponding to the time. Wherein, the Doppler power spectrum fingerprint of any observation time window at the moment is recorded as snThen Doppler power spectrum fingerprint snWith the Doppler power spectrum model S (f, t) to be fittedn) There is a mapping relationship. Therefore, a small amount of spectrum fingerprints are utilized to represent the characteristics of more comprehensive channel fading.
In the process of obtaining the atlas fingerprint, because the measured data amount of the doppler power spectrum is huge (a group of measured data of the doppler power spectrum is obtained in each extremely short observation time), how to effectively select the data with the strongest characterization capability on the doppler power spectrum in each scene becomes a key problem of ensuring the accuracy of the model by fitting and obtaining the model parameters. Therefore, based on the spectrum fingerprint, in order to avoid using all actually measured Doppler power spectrum data, the accuracy of fitting model parameters to be fitted in Doppler power spectrum models to be fitted of each communication scene is improved, scene classification is realized through clustering, and model parameters are fitted by extracting the best data sample (namely, reference fingerprint) in each class. Therefore, in the embodiment of the present invention, the specific implementation manner of step 130 may adopt the following clustering method to cluster the atlas fingerprints and determine multiple types of communication scenarios. The clustering method may include, but is not limited to: any one of a clustering method based on partitioning, a clustering (clustering using RE representations, referred to as CURE for short) algorithm using renewable energy representations, and a clustering method based on a neural network. The clustering method based on the partition is, for example but not limited to, a K-means clustering algorithm or a K-means clustering algorithm, and the clustering method based on the neural network is, for example but not limited to, a Self-organizing map (SOM) algorithm.
Regarding the above-mentioned map features, the above-mentioned step 140 is described below by taking a K-means clustering algorithm as an example.
Step 1, clustering the atlas fingerprints by adopting a K-Means clustering algorithm to obtain atlas fingerprint point sets of K classes; step 2, determining the K classes as communication scenes; and 3, determining the atlas fingerprint corresponding to the centroid of each class as a plurality of reference fingerprint samples. Of course, a plurality of reference fingerprints determined by the atlas fingerprint corresponding to the centroid of each class can be used as the optimal reference data.
The communication scenarios may be distinguished by unique identifiers, such as labels, and are not illustrated here.
And clustering the atlas fingerprints by adopting a K-Means clustering algorithm based on the minimum Euclidean distance to realize the classification of the low-orbit satellite channel multi-scene. The process includes fingerprint normalization, PCA dimension reduction, K-Means clustering, scene labeling, etc., as shown in FIG. 4.
1) And fingerprint standardization: because the numerical magnitudes of the features in the fingerprints are different and the dimensions are different, the distance between the fingerprints cannot be directly calculated, so that the fingerprints need to be standardized, each feature needs to be subjected to dimensionless processing, and the influence of overlarge or undersize values on distance calculation is eliminated. The fingerprints are standardized by a Z-Score method (also called Z-Score standardization), so that the mean value of each characteristic value in all the fingerprints is 0, the standard deviation is 1, and subsequent Principal Component Analysis (PCA) dimension reduction and clustering processing are facilitated.
2) PCA dimensionality reduction to two dimensions: in order to solve Euclidean distance between fingerprints to judge similarity between the fingerprints and realize visual classification and analysis of subsequent clustering processing in a two-dimensional plane space, a PCA method is adopted for reducing dimensions of multi-dimensional fingerprint to two dimensions.
3) The minimum Euclidean distance K-Means clustering algorithm comprises the following steps: by clustering the atlas fingerprints, careful classification of multiple scenes of the measured data is realized, and by two-dimensional visual analysis, optimal reference data to be selected subsequently is used for correctly fitting the model parameters. The clustering method comprises the following steps:
firstly, mapping a graph fingerprint to a two-dimensional plane according to characteristic values on two dimensions to form a point set, then randomly selecting K initial centroids as clustering centers according to K different scenes of measurement experience, calculating Euclidean distance from each point to the center and dividing the Euclidean distance into K clusters, recalculating the centroid of each cluster, and then performing an iterative process of clustering and centroid updating until the centroid is not changed any more. Here, the recalculated centroid per cluster is obtained according to an objective function, the fingerprint data of euclidean distance is considered, Sum of Squared Errors (SSE) is used as an objective function of clustering, after clustering iteration is performed to generate clusters, a sample point with the minimum SSE is used as the centroid of each update, and the objective function and optimization thereof are as follows:
Figure GDA0003163121500000151
where SSE is the sum of squared errors, Σ is the sum, K represents K cluster centers (also called centroids), M is the total number of pattern samples, c is the sum of the squared errors, andiposition coordinates, x, representing the ith cluster centerjIs the position coordinate of the jth fingerprint sample. By aligning the ith centroid ciSolving, minimizing SSE, i.e. differentiating SSE to make derivative function equal to 0, and solving ciThe following formula:
Figure GDA0003163121500000152
wherein argmin (-) is a value of a variable when the function takes a minimum value, arg (-) is a value of a variable when the condition is satisfied,
Figure GDA0003163121500000153
is a partial derivative.
Thus, atlas fingerprint clustering is completed. On the other hand, the clustering of the channel characteristics and the clustering of the doppler power spectrum data are also represented instead by clustering of the profile fingerprints, and the profile fingerprints have fewer feature vectors.
4) Labeling a scene: and after the clustering type iteration process is executed, acquiring the atlas fingerprint point sets of the K types. In the embodiment of the present invention, the scene labels are respectively attached to the classes according to the approximate time corresponding to the previous measurement data, as shown in fig. 5.
After the clustering is completed, each cluster has a centroid. In the following embodiment of the present invention, actually measured data is adopted to fit the doppler power spectrum model parameters of each type of scene in the LEO satellite channel, so that the selection of the actually measured data in each type of scene is crucial to ensure the accuracy of the model. Because the fingerprint points near the centroid of each fingerprint point set are the highest in density, and the characterization capability and the universality of the fingerprint points on the doppler power spectrum characteristics of the scene are also the strongest, the reference fingerprint sample most relevant to the communication scene is selected as the reference fingerprint sample, and the detailed description is as follows:
the embodiment of the invention selects the fingerprint at the centroid of each cluster as the reference fingerprint, and the corresponding measured data is used as the reference data for fitting the scene Doppler power spectrum model. At this time, the reference fingerprint sample according to the embodiment of the present invention is a reference fingerprint in each communication scenario, and a mapping relationship between reference data, the reference fingerprint, and the communication scenario is established, as shown in fig. 6, where K scenarios include: scene 1, scene 2, … …, scene K, each scene corresponding to a reference fingerprint, which includes: reference fingerprint 1, reference fingerprint 2, … …, reference fingerprint K, each reference fingerprint corresponds to doppler power spectrum measured data, it includes: reference data 1, reference data 2, … …, reference data K.
Due to the fact that K-type communication scenes exist, K groups of reference data can be determined, and parameters in the Doppler power spectrum empirical model under each scene are fitted by the K groups of reference data respectively, so that a multi-scene model is obtained. According to the propagation characteristics of the low-orbit satellite signals: the LOS path is obvious, the multipath signals are few, and the fading LOSs and the path number of the LOS path change according to the change of the elevation angle. Therefore, in order to make the measured doppler power spectrum data most approximate to the doppler power spectrum model of the low earth orbit satellite channel finally determined in the embodiment of the present invention in a multi-communication scenario, the step 160 in the embodiment of the present invention further includes:
step 1, obtaining a Doppler power spectrum model to be fitted, wherein the Doppler power spectrum model to be fitted comprises: model parameters to be fitted, including: the method comprises the following steps of a left cut-off frequency point, a right cut-off frequency point, a maximum Doppler shift, a Doppler shift of an LOS path, an influence factor of multi-path power and an influence factor of direct path power.
Describing an LEO satellite channel by using a rice channel, wherein a doppler power spectrum can be represented by a Jakes power spectrum in a double-ended stage and a discrete frequency domain component, and in the step 1, the doppler power spectrum model to be fitted is:
Figure GDA0003163121500000171
wherein S (f) is a predetermined Doppler power spectrum model, rect (f)l,fr) Is in the range ofl,fr]Rectangular window function of flIs a left truncated frequency point, frIs a right cut-off frequency point, alpha is an influence factor of multipath power, pi is a circumferential rate, f is frequency, fmaxFor maximum Doppler shift, β is the influence factor of the direct path power, δ (·) is the Dirichlet function, flosIs the doppler shift of the line of sight, LOS, path. The doppler power spectrum is shown within the dashed line in figure 7.
And 2, generating a target function by using the parameters of the model to be fitted.
The smaller the objective function in the step 2 is, the closer the doppler power spectrum measured data of the embodiment of the present invention is to the doppler power spectrum model of the low earth orbit satellite channel in multiple communication scenarios finally determined by the embodiment of the present invention, so that any objective function that can utilize the reference data and the reference fingerprint in each communication scenario according to the mapping relationship to minimize the value of the objective function belongs to the protection scope of the embodiment of the present invention. For example, the target function is set by the method L2-Norm as:
Figure GDA0003163121500000172
to minimize the value of the objective function, the argmin function can be used, as follows:
fl,fr,fmax,flos,α,β＝argmin(E(fl,fr,fmax,flos,α,β))
wherein, E (f)l,fr,fmax,flosα, β) is an objective function set using the measured data of the Doppler power spectrum, Sexp(f,tn) Is the actual measurement data of Doppler power spectrum in the nth observation time window, wherein ^ integral is integral sign, d in df is infinitesimal, and S (f)l,fr,fmax,flosα, β) is the Doppler power spectrum model to be fitted, argmin is the minimum of the objective function, fl,fr,fmax,flosValues of α, β;
and 3, utilizing the reference data and the reference fingerprints in each communication scene according to the mapping relation to minimize the value of the objective function.
And 4, aiming at each scene, when the target function obtains the minimum value, obtaining the value of the model parameter to be fitted, and obtaining the Doppler power spectrum model of the low-orbit satellite channel in a multi-communication scene.
In the embodiment of the invention, the shape characteristics of the Doppler power spectrum of the LEO satellite multi-communication scene are captured by using the mapping, the mapping relation among the communication scene, the reference fingerprint and the reference data is established, the parameters of the model to be fitted in the Doppler power spectrum model to be fitted of each communication scene are fitted, and the accurate Doppler power spectrum model of the LEO satellite multi-communication scene is obtained. Therefore, the problems that in the LEO satellite channel measurement and modeling process, the parameter fitting result error of the LEO satellite Doppler power spectrum model caused by multi-scene rapid change is large, the model is poor in dynamic performance and accuracy are low are effectively solved, and the accuracy of the wireless channel model is effectively improved.
The following provides a description of a doppler power spectrogram modeling apparatus in a multi-communication scenario according to an embodiment of the present invention.
Referring to fig. 8, fig. 8 is a schematic structural diagram of a doppler power spectrogram modeling apparatus in a multi-communication scenario according to an embodiment of the present invention. The device for modeling the Doppler power spectrogram in the multi-communication scene provided by the embodiment of the invention can comprise the following modules:
the acquiring module 31 is configured to acquire doppler power spectrum measured data of a low-earth-orbit satellite channel in each observation time in multiple types of communication scenes;
the first processing module 32 is configured to perform mapping on the actually measured doppler power spectrum data to determine each doppler power spectrum map;
a constructing module 33, configured to construct an atlas fingerprint of each doppler power spectrum atlas, so that the channel characteristics of the low-orbit satellite correspond to the atlas fingerprint;
a clustering module 34, configured to cluster the atlas fingerprints to determine multiple types of communication scenarios;
the selecting module 35 is configured to select, from fingerprint samples of each type of communication scene, a reference fingerprint sample most relevant to the type of communication scene, where the reference fingerprint sample is a reference fingerprint in each type of communication scene, and a mapping relationship between reference data, the reference fingerprint and the communication scene is established, and the reference data is measured doppler power spectrum data corresponding to the reference fingerprint of each type of communication scene and is used to fit a doppler power spectrum model of each type of communication scene;
and the second processing module 36 is configured to fit model parameters to be fitted in the doppler power spectrum model to be fitted in each communication scene by using the reference data and the reference fingerprint in each communication scene according to the mapping relationship, so as to obtain the doppler power spectrum model of the low-earth-orbit satellite channel in the multiple communication scenes.
Aiming at the time variation of an elevation angle in an LEO satellite channel, the communication scene is diversified and dynamic, and the Doppler power spectrum is influenced. The embodiment of the invention fits the parameters of the model to be fitted in the Doppler power spectrum model to be fitted in each communication scene through actually measured data of the Doppler power spectrum in each communication scene, thereby obtaining the Doppler power spectrum model of the low-orbit satellite channel in the multi-communication scene.
In the process, a group of Doppler power spectrum measured data is obtained within each extremely short observation time, so that the Doppler power spectrum measured data volume is huge, and therefore, how to effectively select the data with the strongest characterization capability on the Doppler power spectrum in each scene to fit and obtain the model parameters becomes a key problem of ensuring the accuracy of the model.
Also, in the modeling for studying the doppler power spectrum, the shape of the doppler power spectrum is an important basis for modeling because the shape can reflect the doppler effect in the channel and the characteristics of the multipath fading. Therefore, according to the doppler power spectrum modeling method and device in the multiple communication scenes provided by the embodiments of the present invention, from the perspective of a graph, the spectrum fingerprint of each doppler power spectrum is extracted based on the geometric features of the doppler power spectrum, then the spectrum fingerprints are clustered to determine multiple types of communication scenes, and then the model parameters to be fitted in the doppler power spectrum model to be fitted in each communication scene are fitted based on the established mapping relationship between the reference data, the reference fingerprint and the communication scenes by using the reference data and the reference fingerprint in each communication scene, so as to obtain the doppler power spectrum model of the low-orbit satellite channel in the multiple communication scenes. The Doppler power spectrum modeling method and device under the multi-communication scene provided by the embodiment of the invention can effectively solve the problems of large parameter fitting result error, low model accuracy and lack of dynamic description of the Doppler power spectrum model of the LEO satellite caused by rapid change of multiple scenes in the measurement and modeling processes of the LEO satellite channel.
In a possible implementation manner, the obtaining module is specifically configured to:
under the low-orbit satellite channel multi-communication scene, measuring a satellite channel to obtain received signal data, wherein the low-orbit satellite channel multi-communication scene comprises: classifying the low-orbit satellite channel communication scenes according to different elevation angle ranges, different terminal motion states and different ground scattering environments to obtain various communication scenes;
and extracting Doppler power spectrum actual measurement data in each observation time from the time domain signal envelope of the received signal data.
In a possible implementation, the construction module is specifically configured to:
extracting geometrical characteristics of an atlas shape according to the corresponding relation between the atlas fingerprints and the channel characteristics of the low-orbit satellite, and constructing the atlas fingerprint of each Doppler power spectrum, wherein the atlas fingerprint comprises the geometrical characteristics, and the geometrical characteristics comprise: width mean, highest point position, kurtosis, skewness and height mean;
and establishing a mapping relation between each spectrum fingerprint and the Doppler power spectrum actual measurement data corresponding to the spectrum fingerprint.
In a possible implementation, the construction module is specifically configured to:
and extracting the geometric characteristics of the shape of the spectrogram by adopting a method based on the geometric image characteristics according to the corresponding relation between the spectrogram fingerprint and the channel characteristics of the low-orbit satellite, and calculating and generating each Doppler power spectrogram fingerprint.
In a possible implementation manner, the clustering module is specifically configured to:
clustering the atlas fingerprints by adopting a K-Means clustering algorithm to obtain K classes of atlas fingerprint point sets;
determining the K classes as communication scenes;
selecting a reference fingerprint sample most relevant to each type of communication scene from the fingerprint samples of each type of communication scene, wherein the selection comprises the following steps:
and determining the atlas fingerprint corresponding to the centroid of each class as a plurality of reference fingerprint samples.
In a possible implementation manner, the second processing module is specifically configured to:
obtaining a Doppler power spectrum model to be fitted, wherein the Doppler power spectrum model to be fitted comprises: model parameters to be fitted, including: the method comprises the following steps of (1) carrying out left truncation frequency point, right truncation frequency point, maximum Doppler shift, Doppler shift of LOS (line of sale) path, influence factors of multipath power and influence factors of direct path power;
generating a target function by using the model parameters to be fitted;
according to the mapping relation, utilizing reference data and reference fingerprints in each communication scene to minimize the value of the target function;
and aiming at each scene, when the objective function obtains the minimum value, obtaining the value of the model parameter to be fitted, and obtaining the Doppler power spectrum model of the low-orbit satellite channel in a multi-communication scene.
In a possible implementation manner, the doppler power spectrum model to be fitted is:
Figure GDA0003163121500000211
the objective function is:
Figure GDA0003163121500000212
the second processing module is specifically configured to:
for each scene, when E (f)l,fr,fmax,flosAlpha, beta) is obtained, the model parameter to be fitted { fl,fr,fmax,flosAnd the value of alpha, beta, obtaining a Doppler power spectrum model of the low-orbit satellite channel in a multi-communication scene.
The following continues to describe the electronic device provided by the embodiment of the present invention.
Referring to fig. 9, fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the present invention. The embodiment of the present invention further provides an electronic device, which includes a processor 41, a communication interface 42, a memory 43 and a communication bus 44, wherein the processor 41, the communication interface 42, and the memory 43 complete mutual communication through the communication bus 44,
a memory 43 for storing a computer program;
the processor 41 is configured to implement the steps (method names) described above when executing the program stored in the memory 43, and in one possible implementation of the present invention, the following steps may be implemented:
acquiring Doppler power spectrum measured data of a low-earth-orbit satellite channel in each observation time under various communication scenes;
mapping the actually measured Doppler power spectrum data to determine each Doppler power spectrum map;
constructing an atlas fingerprint of each Doppler power spectrum atlas so that the channel characteristics of the low-orbit satellite correspond to the atlas fingerprint;
clustering the atlas fingerprints to determine a plurality of types of communication scenes;
selecting a reference fingerprint sample most relevant to the communication scene from fingerprint samples of each communication scene, wherein the reference fingerprint sample is a reference fingerprint under each communication scene, and a mapping relation among reference data, the reference fingerprint and the communication scene is established, and the reference data is Doppler power spectrum actual measurement data corresponding to the reference fingerprint of each communication scene and is used for fitting a Doppler power spectrum model of each communication scene;
and fitting the parameters of the model to be fitted in the Doppler power spectrum model to be fitted in each communication scene by using the reference data and the reference fingerprints in each communication scene according to the mapping relation, so as to obtain the Doppler power spectrum model of the low-orbit satellite channel in the multi-communication scene.
The communication bus mentioned in the electronic device may be a PCI (Peripheral Component Interconnect) bus, an EISA (Extended Industry Standard Architecture) bus, or the like. The communication bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, only one thick line is shown, but this does not mean that there is only one bus or one type of bus.
The communication interface is used for communication between the electronic equipment and other equipment.
The Memory may include a RAM (Random Access Memory) or an NVM (Non-Volatile Memory), such as at least one disk Memory. Optionally, the memory may also be at least one memory device located remotely from the processor.
The Processor may be a general-purpose Processor, including a Central Processing Unit (CPU), a Network Processor (NP), and the like; but also a DSP (Digital Signal Processing), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component.
The method provided by the embodiment of the invention can be applied to electronic equipment. Specifically, the electronic device may be: desktop computers, laptop computers, intelligent mobile terminals, servers, and the like. Without limitation, any electronic device that can implement the embodiments of the present invention is within the scope of the present invention.
An embodiment of the present invention provides a computer-readable storage medium, in which a computer program is stored, and the computer program, when executed by a processor, implements the steps of the doppler power spectrum modeling method in the multi-communication scenario described above.
Embodiments of the present invention provide a computer program product comprising instructions which, when run on a computer, cause the computer to perform the steps of the above-described doppler power spectrum modeling method in a multi-communication scenario.
Embodiments of the present invention provide a computer program, which when running on a computer, causes the computer to perform the steps of the above doppler power spectrum modeling method in a multiple communication scenario.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, as for the apparatus embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims (9)

1. A Doppler power spectrum modeling method under a multi-communication scene is characterized by comprising the following steps:
under the low-orbit satellite channel multi-communication scene, measuring a satellite channel to obtain received signal data, wherein the low-orbit satellite channel multi-communication scene comprises the following steps: classifying the low-orbit satellite channel communication scenes according to different elevation angle ranges, different terminal motion states and different ground scattering environments to obtain various communication scenes;
extracting Doppler power spectrum measured data in each observation time from the time domain signal envelope of the received signal data;
mapping the actually measured Doppler power spectrum data to determine each Doppler power spectrum map;
constructing an atlas fingerprint of each Doppler power spectrum atlas so that the channel characteristics of the low-orbit satellite correspond to the atlas fingerprint;
clustering the atlas fingerprints to determine a plurality of types of communication scenes;
selecting a reference fingerprint sample most relevant to the communication scene from fingerprint samples of each communication scene, wherein the reference fingerprint sample is a reference fingerprint under each communication scene, and a mapping relation among reference data, the reference fingerprint and the communication scene is established, and the reference data is Doppler power spectrum actual measurement data corresponding to the reference fingerprint of each communication scene and is used for fitting a Doppler power spectrum model of each communication scene;
according to the mapping relation, fitting model parameters to be fitted in a Doppler power spectrum model to be fitted in each communication scene by using reference data and reference fingerprints in each communication scene to obtain a Doppler power spectrum model of the low-earth orbit satellite channel in a multi-communication scene, wherein the Doppler power spectrum model to be fitted is the Doppler power spectrum model of the model parameters to be fitted.
2. The method of claim 1, wherein constructing a profile fingerprint for each doppler power spectrum profile such that channel characteristics of the low earth satellite correspond to profile fingerprints comprises:
extracting geometrical characteristics of an atlas shape according to the corresponding relation between the atlas fingerprints and the channel characteristics of the low-orbit satellite, and constructing the atlas fingerprint of each Doppler power spectrum, wherein the atlas fingerprint comprises the geometrical characteristics, and the geometrical characteristics comprise: width mean, highest point position, kurtosis, skewness and height mean;
and establishing a mapping relation between each spectrum fingerprint and the Doppler power spectrum actual measurement data corresponding to the spectrum fingerprint.
3. The method of claim 2, wherein the extracting geometric features of the profile shape according to the correspondence between the profile fingerprint and the channel features of the low-earth satellite, and constructing the profile fingerprint of each doppler power spectrum profile comprises:
and extracting the geometric characteristics of the shape of the spectrogram by adopting a method based on the geometric image characteristics according to the corresponding relation between the spectrogram fingerprint and the channel characteristics of the low-orbit satellite, and calculating and generating each Doppler power spectrogram fingerprint.
4. A method according to claim 2 or 3, wherein the correspondence between the profile fingerprint and the channel characteristics of the low earth orbit satellite comprises:
a one-to-one correspondence between a width mean in the profile fingerprint and a doppler spectrum broadening in a channel feature of the low earth orbit satellite;
the highest point position in the atlas fingerprint is respectively corresponding to the direct path frequency offset and the direct path power in the channel characteristics of the low-orbit satellite;
the kurtosis in the atlas fingerprint is respectively corresponding to fading dynamics, multipath time delay expansion and multipath number in the channel characteristics of the low-orbit satellite;
the skewness in the atlas fingerprint is respectively corresponding to the multipath number and the shadow fading degree in the channel characteristics of the low-orbit satellite;
and the height average value in the atlas fingerprint respectively corresponds to the shadow fading degree and the multipath fading size in the channel characteristics of the low-orbit satellite.
5. The method of claim 1, wherein clustering the graph fingerprints to determine multi-class communication scenarios comprises:
clustering the atlas fingerprints by adopting a K-Means clustering algorithm to obtain K classes of atlas fingerprint point sets;
determining the K classes as communication scenes;
selecting a reference fingerprint sample most relevant to each type of communication scene from the fingerprint samples of each type of communication scene, wherein the selection comprises the following steps:
and determining the atlas fingerprint corresponding to the centroid of each class as a plurality of reference fingerprint samples.
6. The method as claimed in claim 1, wherein the obtaining the doppler power spectrum model of the low earth orbit satellite channel in multiple communication scenarios by fitting the model parameters to be fitted in the doppler power spectrum model to be fitted in each communication scenario with the reference data and the reference fingerprint in each communication scenario according to the mapping relationship comprises:
obtaining a Doppler power spectrum model to be fitted, wherein the Doppler power spectrum model to be fitted comprises: model parameters to be fitted, including: the method comprises the following steps of (1) carrying out left truncation frequency point, right truncation frequency point, maximum Doppler shift, Doppler shift of LOS (line of sale) path, influence factors of multipath power and influence factors of direct path power;
generating a target function by using the model parameters to be fitted;
according to the mapping relation, utilizing reference data and reference fingerprints in each communication scene to minimize the value of the target function;
and aiming at each scene, when the objective function obtains the minimum value, obtaining the value of the model parameter to be fitted, and obtaining the Doppler power spectrum model of the low-orbit satellite channel in a multi-communication scene.
7. The method of claim 6, wherein the doppler power spectrum model to be fitted is:
Figure FDA0003163121490000031
wherein S (f) is a predetermined Doppler power spectrum model, rect (f)l，fr) Is in the range ofl，fr]Rectangular window function of flIs a left truncated frequency point, frIs a right cut-off frequency point, alpha is an influence factor of multipath power, pi is a circumferential rate, f is frequency, fmaxTo a maximum ofThe Doppler shift, beta is the influence factor of the direct path power, delta (·) is the Dirichlet function, flosDoppler shift for line of sight, LOS, path;
the objective function is:
Figure FDA0003163121490000032
wherein, E (f)l，fr，fmax，flosα, β) is the objective function, Sexp(f，tn) Is tnActual measurement data of the Doppler power spectrum at a moment, wherein ^ is integral sign, d in df is infinitesimal, and S (f)l，fr，fmax，flosAnd alpha, beta) is the Doppler power spectrum model to be fitted;
for each scene, when the objective function obtains a minimum value, obtaining a value of the model parameter to be fitted to obtain a doppler power spectrum model of the low-earth orbit satellite channel in a multi-communication scene, including:
for each scene, when E (f)l，fr，fmax，flosAlpha, beta) is obtained, the model parameter to be fitted { fl，fr，fmax，flosAnd the value of alpha, beta, obtaining a Doppler power spectrum model of the low-orbit satellite channel in a multi-communication scene.
8. A Doppler power spectrogram modeling device under a multi-communication scene is characterized by comprising:
the acquisition module is used for acquiring Doppler power spectrum actual measurement data of the low-orbit satellite channel in each observation time under various communication scenes;
the first processing module is used for mapping the actually measured Doppler power spectrum data to determine each Doppler power spectrum map;
the construction module is used for constructing the spectrum fingerprint of each Doppler power spectrum so as to enable the channel characteristics of the low-orbit satellite to correspond to the spectrum fingerprint;
the clustering module is used for clustering the atlas fingerprints to determine a plurality of types of communication scenes;
the selection module is used for selecting a reference fingerprint sample most relevant to each type of communication scene from fingerprint samples of each type of communication scene, the reference fingerprint sample is a reference fingerprint under each type of communication scene, a mapping relation among reference data, the reference fingerprint and the communication scene is established, and the reference data is Doppler power spectrum actual measurement data corresponding to the reference fingerprint of each type of communication scene and is used for fitting a Doppler power spectrum model of each type of communication scene;
the second processing module is used for fitting model parameters to be fitted in a Doppler power spectrum model to be fitted in each communication scene by using the reference data and the reference fingerprints in each communication scene according to the mapping relation to obtain a Doppler power spectrum model of the low-orbit satellite channel in a multi-communication scene, wherein the Doppler power spectrum model to be fitted is the Doppler power spectrum model of the model parameters to be fitted;
the acquisition module is specifically configured to, in the low-earth-orbit satellite channel multi-communication scenario, measure a satellite channel to obtain received signal data, where the low-earth-orbit satellite channel multi-communication scenario includes: classifying the low-orbit satellite channel communication scenes according to different elevation angle ranges, different terminal motion states and different ground scattering environments to obtain various communication scenes; and extracting Doppler power spectrum actual measurement data in each observation time from the time domain signal envelope of the received signal data.
9. An electronic device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;
the memory is used for storing a computer program;
the processor, when executing the program stored in the memory, implementing the method of any of claims 1-7.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107727095A (en) * 2017-09-08 2018-02-23 西安电子科技大学 3D indoor orientation methods based on spectral clustering and weighting reverse transmittance nerve network
CN110049549A (en) * 2019-01-29 2019-07-23 上海无线通信研究中心 More fusion indoor orientation methods and its system based on WiFi fingerprint

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107727095A (en) * 2017-09-08 2018-02-23 西安电子科技大学 3D indoor orientation methods based on spectral clustering and weighting reverse transmittance nerve network
CN110049549A (en) * 2019-01-29 2019-07-23 上海无线通信研究中心 More fusion indoor orientation methods and its system based on WiFi fingerprint

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Doppler characterization for LEO satellites;I. Ali et al;《IEEE Transactions on Communications》;19980331;第46卷(第3期);全文 *
基于环境信息的无线信道指纹研究;张鹏;《中国优秀硕士学位论文全文数据库》;20170615;第7-59页 *

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