阅读说明：本技术 一种低轨卫星通信系统的同频干扰表征方法及装置 (Co-channel interference characterization method and device of low-earth-orbit satellite communication system ) 是由 张海君 彭欢 刘向南 邱宇 隆克平 盛敏 黄颖 李伟 米振强 于 2021-09-10 设计创作，主要内容包括：本发明公开了一种低轨卫星通信系统的同频干扰表征方法及装置,该方法包括：构建低轨卫星通信系统模型；其中,低轨卫星通信系统模型包括多颗卫星和多个地面终端,多颗卫星根据轨道高度被划分为多层；以单个卫星的位置信息为矩阵元素,建立各层卫星的时空位置模型矩阵；基于时空位置模型矩阵和目标终端的位置信息,确定可能对目标终端形成同频干扰的卫星,得到可能对目标终端形成干扰的卫星集合；计算出目标终端的接入容量；同时研究卫星覆盖区内终端上行链路对卫星的同频干扰,给出干扰因子的定义对覆盖区内终端上行链路的同频干扰进行表征,计算出卫星的平均容量。本发明可为星座干扰规避,系统用频规则和星座设计等技术研究提供指导意义。(The invention discloses a same frequency interference representation method and a device of a low earth orbit satellite communication system, wherein the method comprises the following steps: constructing a low-orbit satellite communication system model; the low-earth satellite communication system model comprises a plurality of satellites and a plurality of ground terminals, wherein the satellites are divided into a plurality of layers according to the orbital altitude; establishing a space-time position model matrix of each layer of satellite by taking the position information of a single satellite as a matrix element; determining satellites which may cause co-channel interference to the target terminal based on the space-time position model matrix and the position information of the target terminal to obtain a satellite set which may cause interference to the target terminal; calculating the access capacity of the target terminal; and simultaneously, the co-frequency interference of the terminal uplink in the satellite coverage area to the satellite is researched, the definition of an interference factor is given to represent the co-frequency interference of the terminal uplink in the coverage area, and the average capacity of the satellite is calculated. The invention can provide guiding significance for technical researches such as constellation interference avoidance, system frequency rule and constellation design.)

1. A method for characterizing co-channel interference of a low earth orbit satellite communication system, comprising:

constructing a low-orbit satellite communication system model; the low-earth satellite communication system model comprises a plurality of satellites and a plurality of ground terminals which are communicated with the satellites, wherein the satellites are divided into a plurality of layers according to the orbital altitude, and each layer comprises a plurality of satellites; the plurality of ground terminals conform to homogeneous poisson point distribution;

establishing a space-time position model matrix of each layer of satellite by taking the position information of a single satellite as a matrix element;

determining satellites which are likely to form co-frequency interference on the target terminal based on the space-time position model matrix and the position information of the target terminal to obtain a satellite set which is likely to form interference on the target terminal;

determining the interference suffered by a target terminal based on the satellite set, and calculating the access capacity of the target terminal; and simultaneously, co-frequency interference of the target terminal uplink in the satellite coverage area to the satellite is determined, the definition of an interference factor is given to represent the co-frequency interference of the target terminal uplink in the low-orbit satellite coverage area, and the average capacity of the satellite is calculated.

2. The method according to claim 1, wherein the establishing the spatio-temporal position model matrix of each layer of satellites comprises:

constructing a layered formation matrix model by taking the serial number information of a single satellite as an element; the number information comprises a layer number of a layer where the satellite is located, a track number in the current layer and a position number in the current track;

and performing position modeling on each satellite based on the layered formation matrix model, and converting the position modeling into the position information of a single satellite in a Cartesian coordinate system under the earth center to obtain a space-time position model matrix of each layer of satellite.

3. The method of claim 1, wherein the determining a satellite that may cause co-channel interference to the target terminal based on the spatio-temporal location model matrix and the location information of the target terminal to obtain a set of satellites that may cause co-channel interference to the target terminal comprises:

calculating the distance between the target terminal and each other satellite on the layer where the target satellite is located based on the space-time position model matrix corresponding to the layer where the target satellite is located and the position information of the target terminal;

when the distance between the satellite positioned on the same layer as the target satellite and the target terminal is smaller than a first threshold value, determining that the current satellite is a satellite which is likely to generate co-channel interference on the target terminal, and obtaining a first satellite set which is positioned on the same layer as the target satellite and is likely to generate interference on the target terminal;

calculating the distance between the target terminal and each satellite in other layers based on a space-time position model matrix corresponding to the other layers without the target satellite and the position information of the target terminal;

and when the distance between the satellite of the other layer and the target terminal is smaller than a second threshold value, determining that the current satellite is a satellite which is likely to form co-channel interference on the target terminal, and obtaining a second satellite set which is likely to form interference on the target terminal in the other layer.

4. The method according to claim 3, wherein the co-channel interference of the low earth orbit satellite communication system is characterized in that the interference suffered by the target terminal is determined based on the satellite set, and the access capacity of the target terminal is calculated; meanwhile, co-frequency interference of an uplink of a target terminal in a satellite coverage area to a satellite is determined, the definition of an interference factor is given to represent the co-frequency interference of the uplink of the target terminal in a low-orbit satellite coverage area, and the average capacity of the satellite is calculated, wherein the method comprises the following steps:

calculating the channel gain of a satellite-to-ground link, and integrating and solving the interference of each satellite in the first satellite set on the target terminal based on the channel gain to obtain the same-frequency interference in a single-layer system;

integrating and solving the interference of each satellite in the second satellite set on the target terminal, and calculating the same frequency interference in an interlayer system;

determining average interference based on co-channel interference in a single-layer system and co-channel interference in an interlayer system to obtain the access capacity of the target terminal;

the definition of the interference factor is given to represent the co-channel interference of the low-orbit satellite communication system, and the average capacity of a single satellite is calculated.

5. The method of claim 4, wherein the first threshold is set to a value that is less than a threshold valueThe expression of (a) is as follows:

wherein h is_iIs the orbital altitude, R, of the ith layer satellite_eAnd theta is the minimum elevation angle of satellite coverage, which is the radius of the earth.

6. The method as claimed in claim 5, wherein the target terminal q and the ith layer mn satellite are numberedChannel gain ofThe expression of (a) is as follows:

wherein G is_tFor satellite transmission gain, G_rIn order for the terminal to receive the gain,for the channel attenuation index to be determined by the frequency,representing the satellites with the numbers mn from the q layer to the i layer of the target terminalThe euclidean distance of (c).

7. As claimed in claim 6The co-channel interference characterization method of the low-earth-orbit satellite communication system is characterized in that the co-channel interference in the single-layer systemThe expression of (a) is as follows:

wherein eta is^DLFor co-frequency probability parameters, p, associated with frequency reuse strategies_tIs the transmission power of the satellite signal and,indicating an i-th layer mn numbered communication satellite,indicating a set of satellites in the low-earth layer i satellites that may interfere with the target terminal q.

8. The method of claim 7, wherein the intra-layer intra-system co-channel interference is characterized by the inter-layer intra-system co-channel interferenceThe expression of (a) is as follows:

wherein the content of the first and second substances,representing a target terminal q to a satelliteThe channel gain of (a) is determined,representing a communication satellite numbered mn at layer j,indicating a set of satellites in the low-earth layer j satellites that may interfere with the target terminal q,representing the satellites with the numbers mn from the q to the j layer of the target terminalThe Euclidean distance of (c);

the target terminal q access capacityThe expression of (a) is as follows:

wherein, B is the channel bandwidth, N is the noise power of the satellite-ground link, and j is the number of satellite layers with interlayer interference.

9. The method of claim 8, wherein the interference factor is defined as follows:

target satelliteAverage uplink interference of terminal q in coverage areaThe expression of (a) is as follows:

wherein eta is^ULThe same-frequency probability factor related to the system frequency reuse strategy, lambda is the distribution density of Poisson points obeyed by the terminal, P_t' transmitting a signal frequency, G, for a terminal_t' for terminal antenna transmission gain, G_r' as satellite reception gain, C_aIs the footprint of the satellite;

uplink based average capacity of layer i satellites

Wherein, C_asIs the satellite footprint area and B is the channel bandwidth.

10. An apparatus for characterizing co-channel interference in a low earth orbit satellite communication system, comprising:

the communication system model building module is used for building a low-orbit satellite communication system model; the low-earth satellite communication system model comprises a plurality of satellites and a plurality of ground terminals which are communicated with the satellites, wherein the satellites are divided into a plurality of layers according to the orbital altitude, and each layer comprises a plurality of satellites; the plurality of ground terminals conform to homogeneous poisson point distribution;

the space-time position model matrix construction module is used for establishing a space-time position model matrix of each layer of satellite by taking the position information of a single satellite as a matrix element;

an interference satellite set building module, configured to determine, based on the spatio-temporal location model matrix built by the spatio-temporal location model matrix building module and location information of a target terminal, a satellite that may cause co-channel interference with the target terminal, and obtain a satellite set that may cause interference with the target terminal;

the interference characterization module is used for determining the interference suffered by the target terminal based on the satellite set constructed by the interference satellite set construction module and calculating the access capacity of the target terminal; and simultaneously, co-frequency interference of the target terminal uplink in the satellite coverage area to the satellite is determined, the definition of an interference factor is given to represent the co-frequency interference of the target terminal uplink in the low-orbit satellite coverage area, and the average capacity of the satellite is calculated.

Technical Field

The invention relates to the technical field of satellite communication, in particular to a same frequency interference characterization method and device of a low-earth-orbit satellite communication system.

Background

With the rapid development of science and technology, 5G communication technology and internet technology are rapidly developed, and the scale of the traditional stationary orbit communication market is smaller and smaller. At present, most of global communication satellites mainly use GEO satellites as main components, geosynchronous geostationary satellites can only work in a crowded environment due to limited orbital resources, the orbital height is high, the data transmission delay is large, so that the geosynchronous geostationary satellites are difficult to adapt to the requirements of modern service transmission, the low-orbit satellites can greatly reduce the delay, the delay within 50ms is realized, and the delay is equivalent to a ground optical fiber network, so that the development of a low-orbit satellite communication system becomes a great development trend of the current satellite communication.

On the one hand, the low-earth-orbit satellite has short transmission delay. The path loss is small, the number of satellites is large, the coverage range is wide, the formed constellation can realize real global coverage, and the frequency reuse is more effective; on the other hand, cellular communication, multiple access, spot beam, frequency reuse, etc. also provide technical support for low-orbit satellite mobile communication, so that there are many scholars, and researchers consider that the low-orbit satellite communication system is an important component for establishing future 6G communication, and have already started to perform research and experiments in this respect. At present, in the research aiming at more than ten thousand giant constellation systems, a always ingenious interference analysis method is not provided, and the change rule of the space-time distribution of the interference under the strong time-varying dynamic state of the low-orbit satellite and the constellation scale can be well represented.

Disclosure of Invention

The invention provides a method and a device for representing co-channel interference of a low-orbit satellite communication system, which aim to solve the technical problem that the prior art cannot well represent the co-channel interference in the low-orbit satellite communication system.

In order to solve the technical problems, the invention provides the following technical scheme:

in one aspect, the present invention provides a co-channel interference characterization method for a low earth orbit satellite communication system, including:

constructing a low-orbit satellite communication system model; the low-earth satellite communication system model comprises a plurality of satellites and a plurality of ground terminals which are communicated with the satellites, wherein the satellites are divided into a plurality of layers according to the orbital altitude, and each layer comprises a plurality of satellites; the plurality of ground terminals conform to homogeneous poisson point distribution;

establishing a space-time position model matrix of each layer of satellite by taking the position information of a single satellite as a matrix element;

determining satellites which are likely to form co-frequency interference on the target terminal based on the space-time position model matrix and the position information of the target terminal to obtain a satellite set which is likely to form interference on the target terminal;

determining the interference suffered by a target terminal based on the satellite set, and calculating the access capacity of the target terminal; and simultaneously, co-frequency interference of the target terminal uplink in the satellite coverage area to the satellite is determined, the definition of an interference factor is given to represent the co-frequency interference of the target terminal uplink in the low-orbit satellite coverage area, and the average capacity of the satellite is calculated.

Further, the establishing of the spatio-temporal position model matrix of each layer of satellite includes:

constructing a layered formation matrix model by taking the serial number information of a single satellite as an element; the number information comprises a layer number of a layer where the satellite is located, a track number in the current layer and a position number in the current track;

and performing position modeling on each satellite based on the layered formation matrix model, and converting the position modeling into the position information of a single satellite in a Cartesian coordinate system under the earth center to obtain a space-time position model matrix of each layer of satellite.

Further, determining a satellite which may cause co-channel interference to the target terminal based on the spatio-temporal location model matrix and the location information of the target terminal, and obtaining a set of satellites which may cause interference to the target terminal, including:

calculating the distance between the target terminal and each other satellite on the layer where the target satellite is located based on the space-time position model matrix corresponding to the layer where the target satellite is located and the position information of the target terminal;

when the distance between the satellite positioned on the same layer as the target satellite and the target terminal is smaller than a first threshold value, determining that the current satellite is a satellite which is likely to generate co-channel interference on the target terminal, and obtaining a first satellite set which is positioned on the same layer as the target satellite and is likely to generate interference on the target terminal;

calculating the distance between the target terminal and each satellite in other layers based on a space-time position model matrix corresponding to the other layers without the target satellite and the position information of the target terminal;

and when the distance between the satellite of the other layer and the target terminal is smaller than a second threshold value, determining that the current satellite is a satellite which is likely to form co-channel interference on the target terminal, and obtaining a second satellite set which is likely to form interference on the target terminal in the other layer.

Further, based on the satellite set, determining the interference suffered by a target terminal, and calculating the access capacity of the target terminal; meanwhile, co-frequency interference of an uplink of a target terminal in a satellite coverage area to a satellite is determined, the definition of an interference factor is given to represent the co-frequency interference of the uplink of the target terminal in a low-orbit satellite coverage area, and the average capacity of the satellite is calculated, wherein the method comprises the following steps:

calculating the channel gain of a satellite-to-ground link, and integrating and solving the interference of each satellite in the first satellite set on the target terminal based on the channel gain to obtain the same-frequency interference in a single-layer system;

integrating and solving the interference of each satellite in the second satellite set on the target terminal, and calculating the same frequency interference in an interlayer system;

determining average interference based on co-channel interference in a single-layer system and co-channel interference in an interlayer system to obtain the access capacity of the target terminal;

the definition of the interference factor is given to represent the co-channel interference of the low-orbit satellite communication system, and the average capacity of a single satellite is calculated.

Further, the first threshold valueThe expression of (a) is as follows:

wherein h is_iIs the orbital altitude, R, of the ith layer satellite_eWhich is the radius of the earth, is,the minimum elevation angle is covered for the satellite.

Further, the target terminal q and the ith layer numbered m n satelliteChannel gain ofThe expression of (a) is as follows:

wherein G is_tFor satellite transmission gain, G_rIn order for the terminal to receive the gain,for the channel attenuation index to be determined by the frequency,representing said target terminal q to the i-th layer numbered m n satelliteThe euclidean distance of (c).

Further, co-channel interference in the single-layer systemThe expression of (a) is as follows:

wherein eta is^DLFor co-frequency probability parameters, p, associated with frequency reuse strategies_tIs the transmission power of the satellite signal and,indicating a communication satellite at layer i numbered m n,indicating a set of satellites in the low-earth layer i satellites that may interfere with the target terminal q.

Further, co-channel interference in the inter-layer systemThe expression of (a) is as follows:

wherein the content of the first and second substances,representing a target terminal q to a satelliteThe channel gain of (a) is determined,representing a communication satellite numbered m n at layer j,indicating a set of satellites in the low-earth layer j satellites that may interfere with the target terminal q,representing said target terminal q to a satellite of layer j number m nThe euclidean distance of (c).

The target terminal q access capacityThe expression of (a) is as follows:

wherein, B is the channel bandwidth, N is the noise power of the satellite-ground link, and j is the number of satellite layers with interlayer interference.

Further, the interference factor is defined as follows:

target satelliteAverage uplink interference of terminal q in coverage areaThe expression of (a) is as follows:

wherein eta is^ULThe same-frequency probability factor related to the system frequency reuse strategy, lambda is the distribution density of Poisson points obeyed by the terminal (unit is: number/m)²)，P_t' transmitting a signal frequency, G, for a terminal_t' for terminal antenna transmission gain, G_r' as satellite reception gain, C_aIs the footprint of the satellite.

Uplink based average capacity of layer i satellites

Wherein, C_asIs the satellite footprint area and B is the channel bandwidth.

On the other hand, the invention also provides a co-channel interference characterization device of the low-orbit satellite communication system, which comprises the following steps:

the communication system model building module is used for building a low-orbit satellite communication system model; the low-earth satellite communication system model comprises a plurality of satellites and a plurality of ground terminals which are communicated with the satellites, wherein the satellites are divided into a plurality of layers according to the orbital altitude, and each layer comprises a plurality of satellites; the plurality of ground terminals conform to homogeneous poisson point distribution;

the space-time position model matrix construction module is used for establishing a space-time position model matrix of each layer of satellite by taking the position information of a single satellite as a matrix element;

an interference satellite set building module, configured to determine, based on the spatio-temporal location model matrix built by the spatio-temporal location model matrix building module and location information of a target terminal, a satellite that may cause co-channel interference with the target terminal, and obtain a satellite set that may cause interference with the target terminal;

the interference characterization module is used for determining the interference suffered by the target terminal based on the satellite set constructed by the interference satellite set construction module and calculating the access capacity of the target terminal; and simultaneously, co-frequency interference of the target terminal uplink in the satellite coverage area to the satellite is determined, the definition of an interference factor is given to represent the co-frequency interference of the target terminal uplink in the low-orbit satellite coverage area, and the average capacity of the satellite is calculated.

In yet another aspect, the present invention also provides an electronic device comprising a processor and a memory; wherein the memory has stored therein at least one instruction that is loaded and executed by the processor to implement the above-described method.

In yet another aspect, the present invention also provides a computer-readable storage medium having at least one instruction stored therein, the instruction being loaded and executed by a processor to implement the above method.

The technical scheme provided by the invention has the beneficial effects that at least:

the invention provides a proper modeling mode for analyzing the space-time characteristics of the interference between complex systems of the low-orbit communication system. According to the invention, a giant-constellation low-orbit system is layered according to the orbit height, then the orbit numbers of satellites on the same layer are layered according to the orbit, finally the satellites on the same orbit are numbered, and the position modeling of the satellites is completed through the conversion of a double coordinate system, wherein ground terminals are distributed on Poisson points in the same order in the earth surface. The invention simultaneously and respectively represents the satellite-ground link interference expressions in a single-layer system and among multi-layer systems under the dense giant constellation, analyzes the relationship between the interference and the system scale, the antenna inclination angle and the like, and gives the average access capacity of the system on the basis of the interference in the system and among the systems, and can realize the flexible description and analysis of the time-space correlation of the complex interference of the system under the condition of strong time-varying dynamics of the network structure under the complex system of massive low-orbit satellites; therefore, guiding significance is provided for multi-aspect technical research of improving system capacity, such as constellation interference avoidance, system frequency rule and constellation design.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic flowchart illustrating an implementation of a co-channel interference characterization method for a low-earth orbit satellite communication system according to a first embodiment of the present invention;

fig. 2 is a schematic flowchart illustrating an implementation of a co-channel interference characterization method for a low earth orbit satellite communication system according to a second embodiment of the present invention;

fig. 3 is a schematic view of an application scenario of a co-channel interference characterization method for a low-earth orbit satellite communication system according to a second embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First embodiment

The embodiment provides a co-channel interference characterization method of a low-earth-orbit satellite communication system, which can be realized by electronic equipment. The execution flow of the method is shown in fig. 1, and comprises the following steps:

s1, constructing a low-orbit satellite communication system model; the low-earth satellite communication system model comprises a plurality of satellites and a plurality of ground terminals which are communicated with the satellites, wherein the satellites are divided into a plurality of layers according to the orbital altitude, and each layer comprises a plurality of satellites; the plurality of ground terminals conform to homogeneous poisson point distribution;

s2, establishing a space-time position model matrix of each layer of satellite by taking the position information of a single satellite as a matrix element;

s3, determining satellites which may cause co-channel interference to the target terminal based on the space-time position model matrix and the position information of the target terminal to obtain a satellite set which may cause interference to the target terminal;

s4, determining the interference suffered by the target terminal based on the satellite set, and calculating the access capacity of the target terminal; and simultaneously, co-frequency interference of the terminal uplink in the satellite coverage area to the satellite is determined, the definition of an interference factor is given to represent the co-frequency interference of the terminal uplink in the low-orbit satellite coverage area, and the average capacity of the satellite is calculated.

Further, the establishing of the spatio-temporal position model matrix of each layer of satellite includes:

constructing a layered formation matrix model by taking the serial number information of a single satellite as an element; the number information comprises a layer number of a layer where the satellite is located, a track number in the current layer and a position number in the current track;

and performing position modeling on each satellite based on the layered formation matrix model, and converting the position modeling into the position information of a single satellite in a Cartesian coordinate system under the earth center to obtain a space-time position model matrix of each layer of satellite.

Further, determining a satellite which may cause co-channel interference to the target terminal based on the spatio-temporal position model matrix and the position information of the target terminal, and obtaining a satellite set which may cause interference to the target terminal, including:

calculating the distance between the target terminal and each other satellite on the layer where the target satellite is located based on the space-time position model matrix corresponding to the layer where the target satellite is located and the position information of the target terminal;

when the distance between the satellite positioned on the same layer as the target satellite and the target terminal is smaller than a first threshold value, determining that the current satellite is a satellite which is likely to generate co-channel interference on the target terminal, and obtaining a first satellite set which is positioned on the same layer as the target satellite and is likely to generate interference on the target terminal;

calculating the distance between the target terminal and each satellite in other layers based on a space-time position model matrix corresponding to the other layers without the target satellite and the position information of the target terminal;

and when the distance between the satellite of the other layer and the target terminal is smaller than a second threshold value, determining that the current satellite is a satellite which is likely to form co-channel interference on the target terminal, and obtaining a second satellite set which is likely to form interference on the target terminal in the other layer.

Based on a satellite set, calculating the access capacity of the target terminal, determining the interference suffered by the target terminal and giving out the definition of an interference factor to characterize the co-channel interference of a low-orbit satellite communication system, wherein the method comprises the following steps:

calculating the channel gain of a satellite-to-ground link, and integrating and solving the interference of each satellite in the first satellite set on the target terminal based on the channel gain to obtain the same-frequency interference in a single-layer system;

integrating and solving the interference of each satellite in the second satellite set on the target terminal, and calculating the same frequency interference in an interlayer system; obtaining the access capacity of the target terminal;

determining average interference based on co-channel interference in a single-layer system and co-channel interference in an interlayer system;

the definition of the interference factor is given to characterize the co-channel interference of the low-orbit satellite communication system.

Further, the first threshold valueThe expression of (a) is as follows:

wherein h is_iIs the orbital altitude, R, of the ith layer satellite_eWhich is the radius of the earth, is,the minimum elevation angle is covered for the satellite.

Further, the target terminal q and the ith layer numbered m n satelliteChannel gain ofThe expression of (a) is as follows:

wherein G is_tFor satellite transmission gain, G_rIn order for the terminal to receive the gain,for the channel attenuation index to be determined by the frequency,representing said target terminal q to the i-th layer numbered m n satelliteThe euclidean distance of (c).

Further, co-channel interference in the single-layer systemThe expression of (a) is as follows:

wherein eta is^DLCo-frequency probability factor, p, associated with a system frequency reuse strategy_tIs the transmission power of the satellite signal and,indicating a communication satellite at layer i numbered m n,indicating a set of satellites in the low-earth layer i satellites that may interfere with the target terminal q.

Further, co-channel interference in the inter-layer systemThe expression of (a) is as follows:

wherein the content of the first and second substances,representing a target terminal q to a satelliteThe channel gain of (a) is determined,representing a communication satellite numbered m n at layer j,indicating a set of satellites in the low-earth layer j satellites that may interfere with the target terminal q,representing said target terminal q to a satellite of layer j number m nThe euclidean distance of (c).

The target terminal q access capacityThe expression of (a) is as follows:

wherein, B is the channel bandwidth, N is the noise power of the satellite-ground link, and j is the number of satellite layers with interlayer interference.

Further, the interference factor is defined as follows:

target satelliteAverage uplink interference of terminal q in coverage areaThe expression of (a) is as follows:

wherein eta is^ULLambda is the distribution density of Poisson points obeyed by the terminal (unit: number/m) for the co-frequency probability parameter related to the frequency reuse strategy²)，P_t' transmitting a signal frequency, G, for a terminal_t' for terminal antenna transmission gain, G_r' as satellite reception gain, C_aIs the footprint of the satellite.

Uplink based average capacity of layer i satellites

Wherein, C_asIs the satellite footprint area and B is the channel bandwidth.

In summary, this embodiment provides an interference characterization method under a constellation formation model for interference study of a future ten-thousand-star low-orbit satellite system, and provides a relationship between interference factors and system interference co-system parameters for representing complex interference analysis of a giant constellation system, so as to reveal a space-time evolution mechanism of giant constellation interference, thereby providing technical guidance for a subsequent interference-related study direction of a giant constellation.

Second embodiment

The embodiment provides a co-channel interference characterization method of a low-orbit satellite communication system, and aims to provide a mapping mechanism of complex interference space-time characteristics in the system aiming at the future development of a large-scale complex low-orbit satellite system. The method may be implemented by an electronic device. The execution flow of the method is shown in fig. 2, and comprises the following steps:

step 1: based on Walker constellation configuration as research object, hierarchical formation initialization matrix model of whole giant constellation system is constructed

Specifically, in the present embodiment, tens of thousands of low earth orbit satellites and terrestrial end users are considered. As shown in fig. 2, a multi-layer low earth satellite system leo _ i is also included, with a plurality of terminals on the ground, Q being a set of ground terminals, taking into account the satellite-to-ground communication link between the ground terminals and the low earth satellite.

Numbering the complex ten-thousand-satellite S system, under the condition of no loss of generality, the satellite at the same orbit height is a same-layer system, and the orbit elevation angles in the same-layer system are kept consistent, so that the complex system is arranged according to the orbit height h_iThe high-to-low layers (leo _1, …, leo _ i, leo _ i +1, …) are layered, and the number of orbits N is divided according to the respective orbit planes of the satellite in the layers_iNumber of orbits N_iNumber (1,2 … N …, N)_i) Generally, the number of satellites per orbit in each same layer is M_iSame, for each orbit satellite M_iPerforming M according to the corresponding position relation_iNumber (1,2 … M … M)_i) Thus, each layer is initialized to form a formation model in one-to-one correspondence

Step 2: after the formation model is finished, performing model on the space-time position of the single star according to the transformation of a double coordinate system (an angle coordinate system and an earth center coordinate system)Modeling, establishing space-time position model matrix of each layer of constellation

Wherein the track period of the lower track layer leo _ i is T_i，

In the formula, R_eIs the radius of the earth, G is the gravitational constant; in the angular coordinate system of the space satellite, the orbital inclination angle is theta_i，Ω_{m n}Is the red channel at the ascending intersection point,the included angle between the initialized position under the orbit plane and the ascending node under the angle coordinate system is numbered in Walker constellation (1,2 … M … M)_i) Respectively correspond to each other in sequenceThe initial angle of (a) of (b),the included angle between the running direction of the running time t of the satellite and the rising node is a single satelliteHas a coordinate of (omega) in the angular coordinate system_i,ω_{m n},θ_i)。

And converted into the single-star position of the Cartesian coordinate system under the center of the earthComprises the following steps:

thereby obtaining a space-time position model matrix W of all satellites under each layer system^leo_i

And step 3: the ground terminal Q is set to have a density of lambda UTs/km²Homogeneous Poisson point distribution phi, the frequency factor under the system frequency reuse strategy is K, the frequency occurrence probability is the same, and the position of any known terminal q is w_qMinimum elevation threshold for constellation to ground coverageComputing terminal q and communication satelliteIs a distance of

In the embodiment, in order to research the interference problem of the satellite-ground link, a research object (comprising a target terminal q and a target satellite) is given) Knowing the position of the terminal q as w_q＝(x_q,y_q,z_q)^TIn this case, the spatio-temporal position model matrix W of the low-orbit layer where the target satellite is located^leo_iSearching the position information of the target satellite, calculating the Euclidean distance between the target satellite and the communication satellite in the three-dimensional space, and obtaining the position information of the target satellite and the communication satelliteIs a distance ofComprises the following steps:

and 4, step 4: the space-time position matrix W of the satellite leo _ i is obtained from step 2^leo_iAnd known position information w of the terminal q_qCalculating the space-time distance matrix of the satellite and the terminal q on the layer

Since the condition for the presence of adjacent satellite interference in a satellite system is related to the distance between the adjacent satellite and the terminal (described later), the real-time position relationship matrix of the terminal to all satellites in the leo _ i layer, i.e. D, is calculated^leo_iComprises the following steps:

and 5: according to the position w of the terminal_qSatellite for telecommunicationCalculating the upper threshold of the distance between the satellite which possibly forms co-channel interference to the terminal q and the terminal q in the same layer at the low orbit layer i

Same-layer adjacent satellite interference condition: terminal q is in satelliteThe coverage range (the sight distance LOS propagation range of the ground terminal of the satellite and the requirement of the satellite for covering the minimum elevation angle) at the moment is convertedAfter being in mathematical position relation, the distance between the two is less than the minimum elevation covered by the satelliteThreshold value determined jointly with track height h:

step 6, the space-time distance matrix D in the step 4 is processed^leo_iEach element in (1) and the threshold value obtained in step (5)Comparing (adjacent satellites in the threshold value range may form co-channel interference to the target satellite and the target terminal link) to obtain a satellite set which may form interference to the terminal q in the same layer

And 7: gain G from satellite transmission_tTerminal reception gain G_rTransmission power p of sum signal_tObtaining the channel gain of the satellite-ground link(large scale fading);

after the interference source set is known, calculating link channel gain (in a low-earth orbit satellite network, the distance between a terminal and a satellite is long enough, the influence of the motion of an LEO satellite on the distance can be ignored in a short time, meanwhile, the propagation delay of a satellite-earth link is long, and channel state information is often outdated, so that the influence of large-scale fading on the change of signal strength is large, and only the problem of large-scale fading is generally considered):

wherein G is_tIn order for the satellite to transmit gain, the satellite,G_rin order for the terminal to receive the gain,for frequency dependent channel attenuation index

And 8: the terminal q obtained from the step 6 and the step 7 suffers from the same frequency interference in the single-layer system

Obtaining the same frequency interference in the single-layer system by integrating and solving the interference sourcesIs composed of

Wherein eta is^DLFor co-frequency probability parameters, p, associated with frequency reuse strategies_tIs the transmit power of the satellite signal.

So far, the analysis of the same frequency interference from the terminal to the target satellite by the adjacent satellite in the layer is obtained.

The analysis method for the targeted inter-layer (which may be the inter-giant constellation system layer or other systems) is similar to the intra-layer interference analysis. The method comprises the following specific steps:

and step 9: and repeating the step 4 for the interlayer interference of different low-orbit satellite layers j: obtaining a space-time distance matrix of the layer of satellites and the terminal qAnd (5) repeating the step: calculating the distance upper threshold between the satellite possibly forming co-channel interference to the terminal q in the leo _ j layer and the terminal qAnd repeating the step 6 to obtain leo _ j layers of satellite sets possibly forming interference on the terminal qRepeating the step 8, and calculating the same frequency interference of the terminal q in the interlayer systemGet the terminal q toAccess capacity of

Wherein, the computing terminal q is subjected to the same frequency interference in the interlayer systemIs composed of

After knowing the signal-to-interference ratio according to the Shannon formula, the terminal q reachesAccess capacity ofComprises the following steps:

step 10: the definition of an interference factor phi is given, and the target satellite is deducedAverage uplink interference of terminal q in coverage areaThe expression (2) represents the co-channel interference of the uplink of the low-orbit satellite coverage area terminal, and calculates the average capacity of the satellite.

Aiming at the scene that the ground terminal meets the Poisson point distribution, the number x of terminals which appear when the user terminal is accessed_UTsSatisfy the requirement ofAfter analysis of the mathematical model within the satellite coverage, the coverage area of a single satellite:given the definition of the interference factor:influenced by the parameters of the orbit height, the target satelliteAverage uplink interference of terminal q in coverage area

Wherein eta is^ULThe same-frequency probability factor related to the system frequency reuse strategy, lambda is the distribution density of Poisson points obeyed by the terminal (unit is: number/m)²)，P_t' transmitting a signal frequency, G, for a terminal_t' for terminal antenna transmission gain, G_r' as satellite reception gain, C_aIs the footprint of the satellite (a) according to Campbell's theorem.

From which the average capacity of the uplink-based layer i satellite is derived

Wherein, C_asIs the satellite footprint area and B is the channel bandwidth.

To sum up, the same-frequency interference characterization method of the low-orbit satellite communication system of the embodiment performs layering and layering according to the orbit height on the giant-constellation low-orbit system, then codes the orbit number of the same-layer satellite according to the orbit, then codes the same-orbit satellite, completes the position modeling of the satellite through the conversion of a double coordinate system, and the ground user analyzes the same-frequency interference in the satellite-ground link on the basis of the homogeneous poisson point distribution in the earth surface, characterizes the interference in the same-layer system, and analyzes the space-time relationship between the same-satellite scale and the deployment distribution; representing the internal interference of the interlayer system aiming at different layer systems, and giving the time-space relationship among the same orbit height, the satellite scale and the deployment distribution of the system; then, describing the intra-layer satellite-leading interference and the inter-layer satellite interference by using a giant constellation interference factor, and finally giving capacity prediction of access capacity. The method realizes the complex interference analysis of the giant constellation system, reveals the space-time evolution mechanism of the giant constellation interference, and can provide technical guidance for the relevant research direction of the giant constellation subsequent interference

Third embodiment

The embodiment provides a co-channel interference characterization device of a low earth orbit satellite communication system, which comprises:

the communication system model building module is used for building a low-orbit satellite communication system model; the low-earth satellite communication system model comprises a plurality of satellites and a plurality of ground terminals which are communicated with the satellites, wherein the satellites are divided into a plurality of layers according to the orbital altitude, and each layer comprises a plurality of satellites; the plurality of ground terminals conform to homogeneous poisson point distribution;

the space-time position model matrix construction module is used for establishing a space-time position model matrix of each layer of satellite by taking the position information of a single satellite as a matrix element;

an interference satellite set building module, configured to determine, based on the spatio-temporal location model matrix built by the spatio-temporal location model matrix building module and location information of a target terminal, a satellite that may cause co-channel interference with the target terminal, and obtain a satellite set that may cause interference with the target terminal;

the interference characterization module is used for determining the interference suffered by the target terminal based on the satellite set constructed by the interference satellite set construction module and calculating the access capacity of the target terminal; and simultaneously, co-frequency interference of the target terminal uplink in the satellite coverage area to the satellite is determined, the definition of an interference factor is given to represent the co-frequency interference of the target terminal uplink in the low-orbit satellite coverage area, and the average capacity of the satellite is calculated.

The co-channel interference characterization device of the low-orbit satellite communication system of the embodiment corresponds to the co-channel interference characterization method of the low-orbit satellite communication system of the embodiment; the functions realized by the functional modules in the co-channel interference characterization device of the low-orbit satellite communication system of the embodiment correspond to the flow steps in the co-channel interference characterization method of the low-orbit satellite communication system of the embodiment one by one; therefore, it is not described herein.

Fourth embodiment

The present embodiment provides an electronic device, which includes a processor and a memory; wherein the memory has stored therein at least one instruction that is loaded and executed by the processor to implement the method of the first embodiment.

The electronic device may have a relatively large difference due to different configurations or performances, and may include one or more processors (CPUs) and one or more memories, where at least one instruction is stored in the memory, and the instruction is loaded by the processor and executes the method.

Fifth embodiment

The present embodiment provides a computer-readable storage medium, in which at least one instruction is stored, and the instruction is loaded and executed by a processor to implement the method of the first embodiment. The computer readable storage medium may be, among others, ROM, random access memory, CD-ROM, magnetic tape, floppy disk, optical data storage device, and the like. The instructions stored therein may be loaded by a processor in the terminal and perform the above-described method.

Furthermore, it should be noted that the present invention may be provided as a method, apparatus or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present invention may take the form of a computer program product embodied on one or more computer-usable storage media having computer-usable program code embodied in the medium.

Embodiments of the present invention are described with reference to flowchart illustrations and/or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, embedded processor, or other programmable data processing terminal to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing terminal to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks. These computer program instructions may also be loaded onto a computer or other programmable data processing terminal to cause a series of operational steps to be performed on the computer or other programmable terminal to produce a computer implemented process such that the instructions which execute on the computer or other programmable terminal provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It is further 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. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal 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 terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.

Finally, it should be noted that while the above describes a preferred embodiment of the invention, it will be appreciated by those skilled in the art that, once the basic inventive concepts have been learned, numerous changes and modifications may be made without departing from the principles of the invention, which shall be deemed to be within the scope of the invention. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the embodiments of the invention.