CN117439659B - Ray tracing channel modeling method for low orbit satellite communication - Google Patents
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Abstract
The invention provides a ray tracing channel modeling method for low orbit satellite communication, and relates to the technical field of wireless communication. The method mainly solves the problem that the accuracy of a channel model is low due to incomplete consideration of channel characteristics in the current low orbit satellite channel modeling. The implementation steps are as follows: generating basic parameters of the atmosphere and the near-ground environment, including ionospheric scintillation parameters, rainfall parameters and near-ground environment parameters; channel models considering large-scale and near-earth small-scale fading, including ionosphere scintillation, rainfall attenuation and multipath effect modeling based on ray tracing; and calculating the related parameters of the received power, including power delay spectrums under different near-ground scenes, and total received power under different satellite pitch angles and rainfall rates. The method effectively models the low-orbit satellite channel based on the ray tracing method, considers the ionosphere scintillation and rainfall influence in the atmosphere, has higher accuracy, and has reference value for analysis of the low-orbit satellite channel as a simulation result.
Description
Technical Field
The invention relates to the technical field of wireless communication, in particular to a ray tracking channel modeling method for low-orbit satellite communication.
Background
With the completion of the full set of standards for the first Fifth Generation (5G) mobile communication system, the initial commercial deployment of 5G wireless networks has begun in 2019. However, the revolutionary landscape of 5G is not fully realized. For the universal interconnection (Internet of Everything, ioE) system with huge number of user and equipment connections, the current 5G wireless network still has a plurality of defects. The goal of Sixth Generation (6G) wireless networks is not only to pursue higher transmission rates, but also to continue to extend IoE boundaries and ranges on the basis of 5G wireless network services. Satellite communication networks are an important point of research in 6G wireless networks. Compared with a ground wireless communication system, the satellite communication system has the advantages of wide coverage, large communication capacity and the like. Compared with a high-orbit satellite communication system and a medium-orbit satellite communication system, the low-orbit satellite has the characteristics of low delay, low power consumption, low propagation loss and flexible networking. In recent years, the new generation of internet constellation planning is gradually carried out, and the conversion from low frequency bands such as L (1-2 GHz), S (2-4 GHz) and the like to high frequency bands such as Ku (12-18 GHz), ka (26-40 GHz) and the like is realized. One necessary effort to achieve reliable and efficient transmission of low-orbit satellite communications is to study and model the low-orbit satellite communications channel propagation characteristics.
The low orbit satellite communication channel is affected in many ways, including atmospheric absorption, rainfall attenuation, ionospheric scintillation, doppler shift, etc., and thus has a large time-variability and is difficult to analyze accurately. The existing low orbit satellite channel modeling method comprises geometric-based random channel modeling and ray tracing channel modeling. The existing research models based on a geometric random channel modeling method, the model has higher universality, but under the high accuracy requirement of the current 5G mobile communication system, compared with the geometric random channel modeling method, the ray tracing method has higher accuracy. Some scholars model the low orbit satellite channel in the scenes of helicopters, cities, satellite solar panels and the like based on a ray tracing method, but few scholars consider the influence factors of ionosphere scintillation, rainfall and the like in the atmosphere, and the characteristic analysis of multipath effects in urban areas is not fully studied. In view of the above, an accurate low-orbit satellite channel model is necessary in the demand of 6G wireless communication networks.
Disclosure of Invention
The invention aims to: a method for modeling a ray tracing channel for low orbit satellite communication is provided to solve the above problems in the prior art.
A method for modeling a ray tracking channel for low orbit satellite communication comprises the following steps:
s1, generating low-orbit satellite system parameters; the low-orbit satellite system parameters comprise basic parameters, atmosphere channel environment parameters and near-earth channel environment parameters;
s2, modeling a fading channel of a large-scale part, including ionosphere scintillation fading modeling and rainfall attenuation modeling;
s3, modeling a near-earth small-scale fading channel, including multi-path effect modeling based on a ray tracing method;
s4, calculating the large-scale fading loss and the multipath receiving power of the low-orbit satellite channel based on the steps S1 to S3;
s5, realizing a low orbit satellite simulation channel model according to the step S4, analyzing channel characteristics, and calculating total received power and power delay spectrum.
In a further embodiment, the basic parameters include satellite altitude, pitch angle, operating frequency band, and transmit power;
the satellite-near-ground communication link distance L is calculated as follows:
in the method, in the process of the invention,is the pitch angle of the satellite,is the altitude of the satellite, which is the altitude of the satellite,=6371 km is the earth radius.
The atmosphere channel environment parameters comprise ionosphere scintillation parameters and rainfall parameters;
the ionospheric scintillation parameter S is used to describe the intensity of ionospheric scintillation, and is calculated as follows:
where I is the signal strength, which is proportional to the square root of the signal amplitude;mean averaging in brackets;
the flicker index is generally classified as weak<0.3 Medium (0.3)<<0.6 Strong%<0.6 Three levels). For both the weak and medium level,and (3) with(GHz) has a fixed relationship defined as follows:
in the method, in the process of the invention,n is a flicker index factor for the operating frequency; for the frequency bands above the S band, the flicker index factor n of the multi-field actual measurement result is in the range of-1.6 to-1.9, and the average value of n is-1.7.
The rainfall parameter includes a rainfall rate(mm/h). Rate of rainfallFor the system interrupt rate ofAt a rainfall rate, typically with an average rainfall exceeding 0.01% probabilityTo measure a certain placeRainfall of the zone.
The near-earth channel environment parameters are urban building scene parameters, including building edge outline dimensions, building heights and building surface reflection coefficients.
The outline size of the building edge comprises the coordinates of the edge points of the building and the spacing of the building, and the outline size is calculated according to an actual scene.
Building height has a significant impact on the propagation of electromagnetic waves. The direct path may be obscured by tall buildings and the number of reflected paths may vary due to the varying building heights around the receiving point. Building height as set forth in ITU-R P.1410 recommendationCompliance parametersRayleigh distribution of (2), whereinIs the common building height in urban scenes:
the building surface reflection coefficient is r, which depends on the dielectric constant of the building surface materialIf the included angle between the incident wave and the medium surface isThe following relationship is satisfied:
in a further embodiment, step S2 specifically includes:
s201, modeling ionosphere scintillation fading, and calculating ionosphere scintillation loss according to scintillation index S(dB), the calculation method is as follows:
s202, rainfall attenuation modeling, wherein rainfall on a signal propagation path mainly affects a satellite communication system above 3 GHz. Modeling is firstly based on rainfall intensityAnd satellite pitch angleDetermining equivalent path length experienced by a rainfall zoneThe calculation method is as follows:
second, estimating the fading caused by rainfall according to the rainfall attenuation model proposed by ITU-R P.838：
Wherein the parameters areAndis with the working frequencyPitch angle of satelliteRainfall attenuation coefficient related to polarization tilt angleCan be obtained by looking up ITU-R P.838.
In a further embodiment, step S3 specifically includes:
s301, generating a near-ground equivalent emission circular array. The near-ground equivalent transmitting circular array specifically comprises the step of assuming that a transmitter of a low-orbit satellite always points to a ground terminal. When the transmitted signal propagates in the atmosphere for a long distance, the energy of the signal is uniformly distributed on the cross section in the propagation direction, and reaches the space above the urban building. Electromagnetic waves propagated by low-orbit satellites through the ionosphere above the city are approximately of radius according to the plane wave assumptionIs a circular plane of the lens. The radius depends on the altitude of the satellite. The center of the circle is located on the direct path and its distance to the receiving antenna is fixed. The normal vector v of this plane is the vector of the direct path. The plane uniformly emits a plurality of parallel rays having the same energy along a vector v.
S302, generating multipath based on a ray tracing method. The method for generating multipath by using the ray tracing method specifically comprises the steps of calculating corresponding reflection paths according to a mirror image method when rays emitted by an equivalent circular array pass through the surface of a building, and adopting a radius of at a receiving endIs subject to reception determination. The emitted rays are reflected for one time or multiple times, wherein part of the rays reach the receiving end and are effectively received, and the rays effectively reaching the receiving end are calculated one by one to obtain an accurate propagation path.
In a further embodiment, the low-orbit satellite channel large-scale fading loss is calculated as follows:
in the method, in the process of the invention,is the loss of ionospheric scintillation,is the loss of rainfall,is free space path loss;
the free space path lossIs calculated as follows:
wherein L represents satellite-near ground communication link distance;indicating the operating frequency.
The multipath received powerIs calculated as follows:
wherein,is the time delay of the ith reflection path relative to the direct path,indicating the length of the i-th path,is the transmission power of the light emitted by the light emitting diode,is the wavelength of the signal and,is the reflection coefficient of the light, and,is the phase difference of the ith path relative to the direct path. When a direct path exists, the flow path,=. Each signal reflection causes a loss of signal energy, and third-order and higher reflected signal components are negligible due to annihilation in noise. Thus, the multipath reflection model includes a direct signal, a first order reflection signal, and a second order reflection signal. In the second-order reflected signal,is the product of the two reflection coefficients.
The root mean square delay spread is calculated as follows:
wherein the method comprises the steps ofIs the second moment of the PDP. The RMS delay spread represents the degree of dispersion of the multipath delay.
Therefore, the total multipath received power calculation method is as follows:
total received power(dBm) calculated as follows:
power delay profile(dBm) calculated as follows:
wherein,representing free space path loss;representing ionospheric scintillation loss;indicating rainfall loss;representing the total multipath received power;indicating the length of the i-th path,is the transmission power of the light emitted by the light emitting diode,is the wavelength of the signal and,is the reflection coefficient of the light, and,is the phase difference of the ith path relative to the direct path.
The beneficial effects are that: compared with a geometric random channel modeling method, the low-orbit satellite channel modeling method based on ray tracing has proper complexity and higher accuracy. The invention can change the position distribution and the height distribution of the ground building, thereby being applied to various specific scenes and having higher universality. In addition, the invention compares the model in 3GPP TR 38.811, and obtains similar received power trend. Thus, the present invention enables accurate modeling of the ground communication channel of a low-orbit satellite in an urban environment.
Drawings
Fig. 1 is a flow chart of a method of modeling a ray-traced channel for low-orbit satellite communications.
Fig. 2 is a schematic diagram of a transceiver antenna and radiation propagation in a near-ground scenario in an embodiment of the present invention.
FIG. 3 is a schematic view of a three-dimensional model of a city in an embodiment of the invention.
Fig. 4 (a) is a power delay profile of a dense high-rise scenario.
Fig. 4 (b) is a power delay profile of a residential scenario.
Fig. 5 (a) is a power delay profile of a dense high-rise scenario.
Fig. 5 (b) is a power delay profile of a residential scenario.
Fig. 6 is a graph of received power at different rainfall rates calculated in an embodiment of the present invention.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the invention may be practiced without one or more of these details. In other instances, well-known features have not been described in detail in order to avoid obscuring the invention.
The embodiment discloses a low-orbit satellite communication-oriented ray tracing channel modeling method, and details are shown in fig. 1:
s1, generating basic parameters of a low-orbit satellite system;
s101, the height H of the low orbit satellite is 550 km, the working frequency f is 2 GHz, 28 GHz and 40 GHz respectively, and the transmitting power is high30 dBm, earth radius = 6371 km。
S102, the distance L from the satellite to the ground receiving end can be changed by the pitch angle of the satelliteSatellite altitude H, earth radiusThe calculation is as follows:
s103, the atmosphere channel environment specifically comprises: ionospheric scintillation parameters and rainfall parameters.
The intensity of ionospheric scintillation is typically measured by scintillation indexTo describe, the calculation is as follows:
the flicker index is generally classified as weak<0.3 Medium (0.3)<<0.6 Strong%<0.6 Three levels). For both the weak and medium level,and (3) with(GHz) has a fixed relationship:
wherein,for the operating frequency, n is a flicker index factor. For S-wavesIn the frequency band above the segment, the average value of the flicker index factor n of the measured results is-1.7.
The rainfall parameter comprises rainfall rate(mm/h). Rate of rainfallFor the system interrupt rate ofAt a rainfall rate, typically with an average rainfall exceeding 0.01% probabilityTo measure the rainfall rate in a certain area. Rate of rainfallSetting the thickness to be 0-120 mm/h.
S104, the environment parameters of the near-earth end channel are mainly urban building scene parameters, including building edge outline dimensions, building heights and building surface reflection coefficients.
The building edge outline dimension specifically comprises the coordinates of the edge points of the building and the spacing of the building, and can be obtained according to specific scene data.
Building height has a significant impact on the propagation of electromagnetic waves. The direct path may be obscured by tall buildings and the number of reflected paths may vary due to the varying building heights around the receiving point. Building height as set forth in ITU-R P.1410 recommendationCompliance parametersRayleigh distribution of (2), whereinIs the common building height in urban scenes:
the city model for simulation is set as a city local area composed of 16 buildings according to the followingIn the arrangement, as shown in fig. 3, a road with a width d is arranged between each building, the vertical edge profile of each building is the same, the length along the x-axis direction is a, and the length along the y-axis direction is b.
The simulation sets up dense high-rise scenes and residential area scenes respectively. Wherein, the road width d= m of the dense high-rise scene, the length a= m along the x-axis direction, the length b= m along the y-axis direction, and the parameters=100. Road width d=10 m of residential scene, length a=30 m along x-axis direction, length b=15 m along y-axis direction, parameters =30。
The building surface reflectance r, which depends on the dielectric constant of the building surface material. All reflective planes in the examples are considered as concrete, whose dielectric constant6.2. If the included angle between the incident wave and the medium surface isThe following relationship is satisfied:
s2, modeling a fading channel of a large-scale part, wherein the method specifically comprises the following steps of: ionosphere scintillation fading and rainfall attenuation;
S201. ionosphere scintillation loss(dB) has the following relationship:
at an operating frequency of 2 GHz,when the operating frequency is 10 GHz or higher, the ionospheric scintillation loss is negligible.
S202, simulating different rainfall situations from sunny weather to stormy weather. First according to rainfall intensityAnd satellite pitch angleDetermining equivalent path length experienced by a rainfall zoneThe calculation method is as follows:
the rainfall attenuation calculating method comprises the following steps:
according to ITU-R p.838, at 2 GHz, the rainfall coefficient K is 0.0000847,1.0664; at 28 GHz, the rainfall coefficient K is 0.9679,0.2051; at 40 GHz, the rainfall coefficient K is 0.8673,0.4431.
S3, modeling a near-earth small-scale fading channel, which specifically comprises the following steps: modeling multipath effects;
s301, modeling multipath effect is shown in FIG. 2, and the transmitter of the low-orbit satellite is assumed to always point to the ground terminal. When the transmitted signal propagates in the atmosphere for a long distance, the energy of the signal is uniformly distributed on the cross section in the propagation direction, and reaches the space above the urban building. Electromagnetic waves propagated by low-orbit satellites through the ionosphere above the city are approximately of radius according to the plane wave assumptionCircular plane=5 m. The center of the circle is located on the direct path and its distance to the receiving antenna is fixed, set at 500 m. The normal vector v of this plane is the vector of the direct path. The plane uniformly emits a plurality of parallel rays having the same energy along a vector v.
S302, generating multipath based on a ray tracing method. The method for generating multipath by using the ray tracing method specifically comprises the steps of calculating corresponding reflection paths according to a mirror image method when rays emitted by an equivalent circular array pass through the surface of a building, and adopting a radius of at a receiving endA sphere of=1.5 m makes a reception determination. The emitted rays are reflected for one time or multiple times, wherein part of the rays reach the receiving end and are effectively received, and the rays effectively reaching the receiving end are calculated one by one to obtain an accurate propagation path.
S4, calculating the large-scale fading loss and multipath receiving power of the low-orbit satellite channel;
s401, a large-scale fading calculation method is as follows:
wherein,is ionosphere scintillationThe loss is calculated by the method,is the loss of rainfall,is free space path loss, and the calculation method is as follows:
s402, small-scale fading, including multipath receiving power, is calculated as follows:
wherein,is the time delay of the ith reflection path relative to the direct path,indicating the length of the i-th path,is the transmission power of the light emitted by the light emitting diode,is the wavelength of the signal and,is the reflection coefficient of the light, and,is the phase difference of the ith path relative to the direct path. When a direct path exists, the flow path,=. Each signal reflection causes loss of signal energy, and reflected signal components with third order and above can be annihilated in noiseTo be ignored. Thus, the multipath reflection model includes a direct signal, a first order reflection signal, and a second order reflection signal. In the second-order reflected signal,is the product of the two reflection coefficients.
The root mean square delay spread is calculated as follows:
wherein the method comprises the steps ofIs the second moment of the PDP. The RMS delay spread represents the degree of dispersion of the multipath delay.
Therefore, the total multipath received power calculation method is as follows:
s5, calculating power time delay spectrums under different scenes, multipath receiving powers of different satellite pitch angles and receiving powers of different rainfall rates. From the multipath dataset, a multipath power delay profile may be derived from multipath received power.
Combining ionosphere scintillation loss and rainfall loss, the total received power is:
changing satellite pitch angleRate of rainfallAnd the working frequency, the total received power under different influencing factors can be obtained.
Fig. 4 (a) and fig. 4 (b) show that in the high-rise dense area environment, the receiving antenna receives 3 primary reflection paths in total, the direct reflection paths are shielded by the high-rise, the root mean square delay is expanded to 1.36 ns, and the total received power is-148.8 dBm; in a residential environment, the receiving antenna receives 12 paths in total, wherein one direct path, 10 primary reflection paths and 1 secondary reflection path are included, the root mean square delay spread is 28.02 ns, and the total receiving power is-135.5 dBm. Simulation results show that direct path shielding can possibly occur in a high-rise dense area when the pitch angle of a satellite is low, and the total received power is greatly reduced at the moment, so that the shielding of the direct path is avoided as much as possible when the antenna is deployed. In a residential area, due to the fact that building shielding is rarely generated, the height of a receiving antenna is low, the reflection time delay from a roof is relatively small, the reflection time delay from the side face of the building is relatively large, a secondary reflection path exists, the root mean square time delay expansion is greatly influenced by the reflection path, and the total receiving power is larger.
Fig. 5 (a) and 5 (b) show that in a high-rise dense area, the satellite pitch angle is about 0 to 20 degrees, and the received power does not exist due to the shielding of a building. The satellite pitch angle is about 0-50 degrees, and the total received power steadily rises due to the fact that no reflection path exists and only a direct path exists. When the pitch angle of the satellite is larger than 50 degrees, the influence of reflection paths from the roof generates a multipath effect, so that the total received power has larger jitter along with the increase of the pitch angle, and the total received power generally shows an ascending trend. The results are compared with the model standard of satellite-ground received power in dense urban areas in 3GPP TR 38.811, and it can be seen that the model trend is basically consistent with the 3GPP model standard. The simulated received power is slightly different from the standard calculated value due to the inconsistency with the parameters in the standard. The received power in the high frequency band is different from the standard value because in the L-band (2 GHz), the total received power is affected only by ionospheric scintillation, which is about 6 dB; in the Ka band (28 GHz), the total received power has almost no ionospheric scintillation fading, but the influence of rain fade is prominent, the rain fade size is about 16 dB at a pitch angle of 20 degrees, and the rain fade size is 5.7 dB at a pitch angle of 75 degrees. Simulation results for high-rise dense areas and residential areas show that the residential areas have larger fluctuation of received power, which is caused by stronger multipath effect due to more reflective paths of the residential areas.
Fig. 6 shows the received power versus the rate of rainfall and the operating frequency for different rates of rainfall. At 2 GHz, the received power is hardly affected by rain fade, and at 40 GHz, the received power fade is significant. As can be seen from simulation results, the higher the frequency is, the smaller the received power is, and the influence of rain fade on the millimeter wave frequency band of the low-orbit satellite communication system is larger. To solve the problem of rain fade, the attenuation due to rain absorption can be reduced with narrower beamwidth antennas.
In summary, the method for modeling the ray tracking channel for the low-orbit satellite communication, which is established by the invention, considers the ionosphere scintillation and rainfall influence in the atmosphere, models the near-ground multipath effect by adopting a circular emission area array equivalent method, has higher accuracy, moderate complexity and better universality, enriches the modeling method of the low-orbit satellite channel, and has reference value for the design of a low-orbit satellite communication system due to the simulated statistical characteristics.
The present invention is not described in detail in the present application, and is well known to those skilled in the art.
As described above, although the present invention has been shown and described with reference to certain preferred embodiments, it is not to be construed as limiting the invention itself. Various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (1)
1. A method for modeling a ray tracking channel for low-orbit satellite communication is characterized by comprising the following steps:
s1, generating low-orbit satellite system parameters; the low-orbit satellite system parameters comprise basic parameters, atmosphere channel environment parameters and near-earth channel environment parameters;
the basic parameters comprise satellite altitude, pitch angle, working frequency band and transmitting power;
according to the basic parameters, calculating and obtaining the satellite-near ground communication link distance L:
；
in the method, in the process of the invention,is satellite pitch angle>Is satellite altitude, & ->Is the earth radius;
the atmosphere channel environment parameters comprise ionosphere scintillation parameters and rainfall parameters;
the ionospheric scintillation parameter S is used to describe the intensity of ionospheric scintillation, and is calculated as follows:
；
where I is the signal strength, which is proportional to the square root of the signal amplitude;mean averaging in brackets;
the ionized layer scintillation parameter S and the ionized layer scintillation frequency satisfy the following relation:
；
in the method, in the process of the invention,n is a flicker index factor for the operating frequency;
the rainfall parameter comprises a rainfall rate; the rainfall rate is the rainfall rate when the system interruption rate is preset;
the near-earth channel environment parameter is an urban building scene parameter; the urban building scene parameters comprise building edge outline dimensions, building heights and building surface reflection coefficients;
the outline size of the edge of the building comprises the coordinates of the edge points of the building and the spacing of the building;
the building heightCompliance with parameters->Rayleigh distribution->：
；
In the parameters ofRepresenting a generalized building height within a city scene;
the expression of the building surface reflection coefficient r is as follows:
；
in the method, in the process of the invention,represents the dielectric constant of the building surface material; />Representing the angle between the incident wave and the medium surface;
s2, modeling a fading channel of a large-scale part, including ionosphere scintillation fading modeling and rainfall attenuation modeling;
the ionosphere scintillation fading modeling comprises the steps of calculating ionosphere scintillation loss according to a scintillation index:
；
in the method, in the process of the invention,the ionospheric scintillation loss is expressed in dB; s represents ionospheric scintillation parameters;
the rainfall attenuation modeling includes:
according to rainfall intensityAnd satellite pitch->Determining the equivalent path length experienced by a rainfall zone +.>：
；
Calculating fading caused by rainfall：
；
In the parameters ofAnd->Is +.>Satellite pitchingCorner->Rainfall attenuation coefficient related to polarization tilt angle;
s3, modeling a near-earth small-scale fading channel, including multi-path effect modeling based on a ray tracing method;
s301, generating a near-ground equivalent emission circular array:
assuming that the transmitter of the low-orbit satellite is always directed to the ground terminal; when the transmitted signal propagates in the atmosphere for a long distance, the energy of the signal is uniformly distributed on the cross section in the propagation direction and reaches the upper space of the urban building;
electromagnetic waves propagated by low-orbit satellites through the ionosphere above the city are approximately of radius according to the plane wave assumptionIs circular in plane, radius->Depending on the altitude of the satellite;
the center of the circular plane is located on the direct path and its distance to the receiving antenna is fixed; the normal vector v of the circular plane is the vector of the direct path; the circular plane uniformly emits a plurality of parallel rays with the same energy along a vector v;
s302, generating multipath based on a ray tracing method:
when the rays emitted by the equivalent circular array pass through the surface of a building, corresponding reflection paths are calculated according to a mirror image method, and at a receiving end, the radius is adoptedIs subjected to receiving judgment;
the emitted rays are subjected to single reflection or multiple reflections, wherein part of the rays reach the receiving end and are effectively received, and the rays effectively reaching the receiving end are calculated one by one to obtain an accurate propagation path;
s4, calculating the large-scale fading loss and the multipath receiving power of the low-orbit satellite channel based on the steps S1 to S3;
the large-scale fading loss PL of the low-orbit satellite channel is calculated as follows:
；
in the method, in the process of the invention,is ionospheric scintillation loss, < >>Is rainfall loss, is->Is free space path loss;
the free space path lossIs calculated as follows:
；
wherein L represents satellite-near ground communication link distance;representing the operating frequency;
the multipath received powerIs calculated as follows:
；
in the method, in the process of the invention,is the ith inverseDelay of radial versus direct radial +.>Represents the length of the ith path, +.>Is the transmit power, +.>Is the signal wavelength, < >>Is the reflection coefficient>Is the phase difference of the ith path relative to the direct path;
s5, calculating total received power and a power delay spectrum according to the large-scale fading loss and the multipath received power obtained by calculation in the step S4;
the total received powerIs calculated as follows:
；
in the method, in the process of the invention,representing free space path loss; />Representing ionospheric scintillation loss; />Indicating rainfall loss; />Representing the total multipath received power;
the total multipath received powerIs calculated as follows:
；
in the method, in the process of the invention,represents the length of the ith path, +.>Is the transmit power, +.>Is the signal wavelength, < >>Is the reflection coefficient of the light, and,is the phase difference of the ith path relative to the direct path;
the power delay profileIs calculated as follows:
；
in the method, in the process of the invention,representing multipath received power; />Representing free space path loss; />Representing ionospheric scintillation loss; />Indicating rainfall loss; />Indicating the operating frequency.
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| CN101860384A (en) * | 2010-04-23 | 2010-10-13 | 北京航空航天大学 | Ionosphere hybrid modeling method in short-wave ray tracing technique |
| CN104596544A (en) * | 2015-01-23 | 2015-05-06 | 北京航空航天大学 | Method for predicting airborne navigation performances under ionospheric scintillation |
| US10819454B1 (en) * | 2018-11-30 | 2020-10-27 | United States of America as Represented by the Adminstrator of National Aeronautics and Space Adminstration | Vortex radiometers for cognitive antenna applications and fade prediction techniques |
| CN116346246A (en) * | 2022-11-18 | 2023-06-27 | 国网山东省电力公司信息通信公司 | Evaporation waveguide beyond-view-range emergency communication modeling method and system based on ray tracing |
| CN116800364A (en) * | 2023-07-18 | 2023-09-22 | 天津大学 | LUNA lunar base communication channel method based on ray tracing method |
| CN117040670A (en) * | 2023-08-30 | 2023-11-10 | 东南大学 | Geometric random channel modeling method for satellite channel |
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| CN101860384A (en) * | 2010-04-23 | 2010-10-13 | 北京航空航天大学 | Ionosphere hybrid modeling method in short-wave ray tracing technique |
| CN104596544A (en) * | 2015-01-23 | 2015-05-06 | 北京航空航天大学 | Method for predicting airborne navigation performances under ionospheric scintillation |
| US10819454B1 (en) * | 2018-11-30 | 2020-10-27 | United States of America as Represented by the Adminstrator of National Aeronautics and Space Adminstration | Vortex radiometers for cognitive antenna applications and fade prediction techniques |
| CN116346246A (en) * | 2022-11-18 | 2023-06-27 | 国网山东省电力公司信息通信公司 | Evaporation waveguide beyond-view-range emergency communication modeling method and system based on ray tracing |
| CN116800364A (en) * | 2023-07-18 | 2023-09-22 | 天津大学 | LUNA lunar base communication channel method based on ray tracing method |
| CN117040670A (en) * | 2023-08-30 | 2023-11-10 | 东南大学 | Geometric random channel modeling method for satellite channel |
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