CN116722903A - Dynamic wave beam switch management method in low orbit satellite mobile communication scene - Google Patents
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Abstract
The invention discloses a dynamic beam switch management method in a low orbit satellite mobile communication scene, which belongs to the technical field of wireless communication and comprises the steps of designing a user beam which can be dynamically closed and takes a user as a center; constructing a space model suitable for a digital multi-beam LEO satellite mobile communication scene, and establishing a mathematical model for calculating constellation network topological relation in real time; the dynamic change of the satellite seat network topological relation during the satellite in-orbit operation is studied in depth, and the problem of optimizing and designing the number of beams required by minimizing LEO satellite constellation under the condition of meeting the constraint of system communication requirements is solved; the optimization problem is further converted into the sum of the number of active beams which can be provided by each satellite on the basis of the closable beam forming design, and a dynamic user switch management method is further provided. The invention can dynamically adjust the beam switch according to the link topological relation and the number of users in the constellation network, effectively reduces the energy consumption of the system and further improves the utilization rate of beam resources.
Description
Technical Field
The invention relates to the technical field of wireless communication, in particular to a dynamic beam switch management method in a low-orbit satellite mobile communication scene.
Background
In recent years, emerging low-earth orbit (LEO) satellite communication systems have assumed a potential for vigorous development, mainly including OneWeb, telesat and Starlink. With increasing communication demands, the global LEO satellite mobile communication system is continually advancing toward providing full-time, full-earth, and high-quality access as a core component of a converged communication system. Thus, there is a need to build a system architecture in combination with a terrestrial infrastructure, including satellite constellation design and coverage schemes, that ensures global seamless coverage. Currently, multi-beam antenna (MBA) technology, which is one of key technologies for multi-user satellite communication, has been widely adopted by LEO satellite communication systems, has good coverage performance, and can achieve global coverage. Communication systems consisting of multiple MBA-equipped LEO satellites can achieve true global coverage and more efficient frequency reuse.
For a multi-beam LEO satellite system, the coverage area of a beam is continuously changed due to the rapid movement of a satellite, so that the beam faces the problems of space-time transformation, user distribution, service requirements and the like. For the near polar orbit constellation, as the orbit of the satellite is fixed, the distance between adjacent satellites is gradually reduced along with the rise of the latitude of the point below the satellite, the repeated coverage of the satellite is continuously expanded, and the coverage ratio of the beams with low latitude and high latitude is different. In order to solve the problem of beam resource waste caused by the phenomena of beam overlapping coverage and the like, the beams are required to be subjected to switch management so as to improve the utilization rate of system resources.
Disclosure of Invention
The invention provides a dynamic beam switch management method under a low orbit satellite mobile communication scene, which is based on a low orbit satellite constellation, provides a dynamic beam switch management strategy applicable to an LEO satellite mobile communication scene based on a dynamic beam forming mode, and researches the number of beams required by the LEO satellite mobile communication system to minimize the LEO satellite constellation under the condition of meeting communication requirement constraint.
The embodiment of the invention provides a dynamic beam switch management method in a low-orbit satellite mobile communication scene, which comprises the following steps: designing a user beam which can be dynamically closed and takes a user as a center; constructing a mathematical model suitable for a digital multi-beam low-orbit satellite mobile communication scene and used for calculating the constellation network topological relation in real time; establishing an optimal design problem of minimizing the number of beams required by a low-orbit satellite constellation under the constraint of system communication requirements; and carrying out a dynamic user beam switch management method based on the optimal design problem.
Alternatively, in one embodiment of the present invention, designing a user beam that can be dynamically turned off and centered on a user includes:
based on the downlink transmission scene of the low-orbit satellite, the phased array of the low-orbit satellite is provided with a dynamic multi-beam digital beam shaper and is N at the same time K A single antenna user provides communication services, and a low orbit satellite is provided with a uniform plane array, which is formed by N T ＝M x M y An antenna array element, wherein M x and My The number of antenna elements on the x and y axes, respectively;
at time t and frequency f, the channel model from the low-orbit satellite to the kth user can be modeled as:
wherein ,vsat Representing doppler shift due to the fast movement of the low orbit satellite,represents the minimum path delay, g, of the kth user k (t, f) represents the downlink channel gain of the kth user, including large scale fading and different pathsGain information->Array response vector, N, for a uniform planar array of satellites T The number of the antenna array elements;
defining s_ { k } as data transmitted from the low-orbit satellite to the kth user, the received signal of the kth user is expressed as wherein ,/>Mean value zero, variance ++>Additive white gaussian noise of +.>DBF vector, N, representing kth user RF The number of the radio frequency links;
establishing a transmission model of an all-digital phased array antenna equipped satellite communication system, denoted as y= HWs +n, whereinFor a channel matrix>In order to pre-code the matrix,representing AWGN vectors, each element obeys +.>Mean zero variance +.>Is a complex Gaussian distribution of->w k Satisfy->Wherein P is the power constraint, and the total power transmitted by the system is recorded as P total ；
The satellite side performs switching operation on satellite carrier beams through beam allocation instructions of a ground station on the basis of a dynamic all-digital multi-beam forming architecture, and a power allocation factor is determined by an input channel matrix H and a dimension thereof, wherein the dimension H represents the number of current satellite on beamsThe H dimension does not exceed the number N of beams available to the satellite B The baseband digital beamforming matrix W may be obtained by beam design with the precoding matrix W as the beamforming matrix input D And a power division factor, so as to adjust the power divider, so that the port power constraint of the system corresponding to the beam to be turned off is 0, and the port total power constraint of the beam to be turned on is +.>To turn on and off the selected set of beams.
Optionally, in one embodiment of the present invention, constructing a mathematical model suitable for a digital multi-beam low orbit satellite mobile communication scenario for calculating a constellation network topology relationship in real time includes:
defining a satellite plane local coordinate system: the origin of coordinates O is defined as the mass center of the satellite, the +Z axis is defined as the direction from the satellite to the earth's center of earth, the +X axis is defined as the moving direction, and the +Y axis direction is determined by the principle of a right-hand coordinate system;
let the number of satellites in the low orbit satellite constellation of the current communication system be N S The satellite in the constellation is s i ，i＝1,2,...,N S Record satellite setThe number of users is N K By usingHouse u j ，j＝1,2,...,N K Record user setThe number of beams of each satellite is N B The total number of the beams of the system is N B,tot ＝N S N B Beam set->In beam set +.>In assigning a beam to each user terminalAnd the other coverage beams are turned off. Set satellite s i The user set of the service is->User u j Communication satellite set->For beam b ij In other words, under the satellite local coordinate system, the spatial orientation is defined +.>To indicate the beam pointing, each user is assigned a beam and the beam center is pointed to the user according to dynamic multi-beam digital beamforming techniques, when beam b ij The served user is u k When its spatial orientation is converted into +.>
Optionally, in one embodiment of the present invention, establishing an optimization design problem that minimizes the number of beams required for the low-orbit satellite constellation to meet the system communication requirement constraints includes:
definition of user terminal-satellite related coverage factor c i,k Representing the kth user terminal u k Whether or not at the ith satellite s i Within the communication service range of c i,k The expression is:
defining a beam state factor a ij To characterize the beam in an active or off state, a ij The calculation formula is as follows:
establishing an optimization problem of beam switch management:
establishing constraint conditions: a) Ensuring coverage of the service area; b) The coverage mode of providing user beam communication by the satellite is a service mechanism taking users as centers, and a beam is distributed to each user to realize beam staring; the expression is as follows:
optionally, in an embodiment of the present invention, a method for performing dynamic user beam switch management based on the optimization design problem includes:
definition of satellites s i Serving beam-user terminal pairing set as
By realizing that each user distributes a beam according to the design result of the user beam and the beam center points to the user terminal, the optimization goal of minimizing the beam quantity can be realized by reasonably selecting a proper satellite for each user to provide a user service beam, and the satellites s are defined i Serving beam-user terminal pairing set asThe optimization problem can be translated into:
wherein ,representing the set of beam-user pairs +.>Of elements, i.e. satellites s i The number of user beams provided;
based on the optimization design problem, the satellite load and satellite selection criteria are considered to dynamically manage the user beam switch.
Optionally, in one embodiment of the present invention, dynamically managing the user beam switch based on the optimization design problem, taking into account satellite load and satellite selection criteria, includes:
initializing the number N of user terminals K Number of satellites N S Number of beams N provided by each satellite B Satellite cluster covered by user
Determining the position information of each satellite and the user terminal at the current moment;
determining satellites in a systemIs +.>The coverage relation between them to determine the coverage factor c i,k To obtain the value of each user u k Covered satellite set +.>
Statistical aggregation clusterIs>The number of elements of (2) are ordered from small to large, and the ordered aggregation cluster +.>
Per cluster setAre>Order, determining the preamble user u k ；
In communicable satellites according to the principle of least-priority of channel lossSatellite s with minimum channel fading i ；
Judging satellite s i Set of provided beam-user pairsThe number of elements is less than or equal to N B If smaller than, user u k Selecting the satellite and assigning a beam thereto; otherwise, satellite s i Is full, other satellites within communication range need to be selected, return per cluster +.>Are>Order, determining the preamble user u k A step of;
judging whether users in the system have all selected completely, if not, clustering the setAre>The next user terminal u corresponding in sequence k′ Satellite selection and beam allocation are performed, i.e. let k=k', return per cluster +.>Are>Order, determining the preamble user u k A step of; otherwise, jumping out of the circulation;
output aggregation cluster
The dynamic beam switch management method in the low orbit satellite mobile communication scene of the embodiment of the invention considers the problems of low system resource occupancy rate caused by the surplus of the scarce beam resources of the users in the communication cold spot area under the LEO satellite mobile communication system, and the like.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
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The foregoing and/or additional aspects and advantages of the invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:
fig. 1 is a flowchart of a dynamic beam switch management method in a low-orbit satellite mobile communication scenario according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a space model provided according to an embodiment of the present invention;
fig. 3 is a graph of the number of on beams and the latitude of the point under the satellite after tracking the satellite 1 in the simulation process according to the embodiment of the present invention, where the dynamic user beam switching strategy is adopted. Wherein, latitude is positive value and indicates north latitude, and latitude is negative value and indicates south latitude.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
Fig. 1 is a flowchart of a dynamic beam switch management method in a low-orbit satellite mobile communication scenario according to an embodiment of the present invention.
As shown in fig. 1, the dynamic beam switch management method in the low-orbit satellite mobile communication scenario includes the following steps:
in step S1, a user beam that can be dynamically turned off and user-centric is designed.
In an embodiment of the present invention, a user beam that can be dynamically turned off and user centric is designed according to the following steps:
s11: consider a LEO satellite downlink transmission scenario in which a LEO satellite phased array is equipped with a dynamic multi-beam digital beamformer with N at the same time K A single antenna user provides communication services. Let LEO satellites are assumed to be equipped with a uniform planar array, consisting of N T ＝M x M y An antenna array element, wherein M x and My The number of antenna elements on the x and y axes, respectively.
S12: at time t and frequency f, the LEO satellite to kth user channel model can be modeled as wherein vsat Indicating Doppler shift due to rapid movement of LEO satellites, < >>Represents the minimum path delay, g, of the kth user k (t, f) represents the downlink channel gain of the kth user, including large-scale fading and gain information under different paths. Array response vector of satellite uniform planar array>Is defined as wherein ,/> and θk The angles of the kth user with respect to the x-axis and the y-axis are shown respectively, and />The response vectors of the UPA with respect to the x and y axes are:
s13: defining s_ { k } as the data sent by LEO satellite to kth user, the received signal of kth user is expressed as wherein ,/>Mean value zero, variance ++>Additive white gaussian noise of (c). Supposing signal s k The average power of (2) is 1, i.e. +.> DBF vector representing kth user:
s14: defining the joint representation of the transmitted signals of K users as s= [ s ] 1 ,s 2 ,...,s K ] T The received signals of K users are expressed as y= [ y ] 1 ,y 2 ,...,y K ] T ；
S15: modeling a transmission for an all-digital phased array antenna equipped satellite communication system may be represented as y= HWs +n, whereFor a channel matrix>In order to pre-code the matrix,representing AWGN vectors, each element obeys +.>Mean zero variance +.>Is a complex Gaussian distribution of->w k Satisfy->Wherein P is the power constraint, and the total power transmitted by the system is recorded as P total ；
S16: the satellite side performs switching operation on the satellite carrier beam through a beam allocation instruction of the ground station on the basis of a dynamic all-digital multi-beam forming architecture, namely, the satellite carrier beam is realized by adjusting a power allocation factor and a baseband digital beam forming vector. The power allocation factor can be determined by the channel matrix H entered above, i.e. the number of beams characterizing the current satellite on, and its dimensionsThe H dimension does not exceed the number of beams $n_b$ available to the satellite. The baseband digital beamforming matrix W may be obtained by beam design with the precoding matrix W as the beamforming matrix input D And a power division factor, thereby adjusting the power divider to make the port power constraint of the system corresponding to the beam to be turned off be 0, and the port total power constraint of the beam to be turned on beTo turn on and off the selected set of beams.
In step S2, a mathematical model suitable for a digital multi-beam low orbit satellite mobile communication scenario is constructed for calculating the constellation network topology relationship in real time.
Specifically, the embodiment of the invention establishes a digital multi-beam LEO satellite mobile communication scene and a mathematical model for calculating the constellation network topological relation in real time according to the following steps:
s21: the satellite plane local coordinate system (SPL, satellite Plane Local Coordinate) system, which is based on the coordinates of the satellite platform, is defined as: the origin of coordinates O is defined as the satellite centroid, +z axis is defined as the satellite to earth centroid direction, +x axis is defined as the movement direction, +y axis direction is determined by the right hand coordinate system principle as shown in fig. 2.
S22: let the number of satellites in the low orbit satellite constellation of the current communication system be N S The satellite in the constellation is s i ，i＝1,2,...,N S Record satellite setThe number of users is N K User u j ，j＝1,2,...,N K Record user set->The number of beams of each satellite is N B The total number of the beams of the system is N B,tot ＝N S N B Beam set->In beam set +.>In assigning a beam to each user terminalAnd the other coverage beams are turned off. Set satellite s i The user set of the service is->User u j Communication satellite set->For beam b ij In other words, under the satellite local coordinate system, spatial orientation can be defined>To indicate the beam pointing direction. The dynamic multi-beam digital beamforming technique according to step S1 may be implemented such that each user is assigned a beam and the beam center is directed towards the user. Thus, when beam b ij The served user is u k In this case, its spatial orientation can be converted into +.>
In step S3, an optimization design problem is established that minimizes the number of beams required for the low-orbit satellite constellation to meet the system communication requirement constraints.
In an embodiment of the invention, the conversion is performed according to the following steps:
s31: definition of user terminal-satellite related coverage factor c i,k Representing the kth user terminal u k Whether or not at the ith satellite s i Is within communication service range of (a). c i,k The expression is:
defining a beam state factor a ij To characterize whether the beam is in an active or off state. a, a ij The calculation formula is as follows:
s32: establishing an optimization problem of beam switch management:
s33: establishing constraint conditions: a) Ensuring coverage of a service area, i.e. in case of several beams being off, for any terminal within the service area, satellites providing active beams for it can cover the terminal; b) The coverage mode of providing user beam communication by the satellite is a service mechanism with a user as a center, and each user is allocated with a beam to realize beam staring. The expression is as follows:
in step S4, the dynamic user beam switch management method is performed based on the optimization design problem.
In an embodiment of the invention, the following steps are followed:
s41: definition of satellites s i Serving beam-user terminal pairing set as
S42: by the result in S1 it is possible to achieve that each user is assigned a beam and the beam centre is directed towards the user terminal, and the optimization objective of minimizing the number of beams can be achieved by each user by reasonably selecting a suitable satellite to provide a user service beam. Definition of satellites s i Serving beam-user terminal pairing set asThe optimization problem can be translated into:
wherein ,representing the set of beam-user pairs +.>Of elements, i.e. satellites s i The number of user beams provided;
s43: based on the above-mentioned optimization design problem, the user beam switch is dynamically managed in consideration of satellite load and satellite selection criteria.
Further, the step S43 specifically includes the following sub-steps:
s431: initializing the number N of user terminals K Number of satellites N S Number of beams N provided by each satellite B Satellite cluster covered by user
S432: determining the position information of each satellite and the user terminal at the current moment;
s433: determining satellites in the system according to step S31Is +.>The coverage relation between them to determine the coverage factor c i,k To thereby obtain the value of each user u k Covered satellite set +.>
S434: statistical aggregation clusterIs>The number of elements of (2) are ordered from small to large, and the ordered aggregation cluster +.>
S435: per cluster setAre>Order, determining the preamble user u k ；
S436: in communicable satellites according to the principle of least-priority of channel lossSatellite s with minimum channel fading i ；
S437: judging satellite s i Set of provided beam-user pairsThe number of elements is less than or equal to N B . If smaller than, user u k Selecting and assigning the satelliteBeams, i.e. in the aggregate->Add (+)>Element number, k); otherwise, satellite s i Is full, other satellites within communication range need to be selected, i.e. in the set +.>Delete s in i And returns to step S435;
s438: and judging whether the users in the system have finished selecting. If not, then to the clusterAre>The next user terminal u corresponding in sequence k′ Performing satellite selection and beam allocation, i.e. let k=k', returning to step S435; otherwise, jumping out of the circulation;
s439: output aggregation cluster
Fig. 3 shows the number of on beams versus the latitude of its understar spot for tracking satellite 1 after employing a dynamic user beam switching strategy.
According to the dynamic beam switch management method in the low orbit satellite mobile communication scene, the user beam which can be dynamically closed and takes the user as the center is designed; constructing a space model suitable for a digital multi-beam LEO satellite mobile communication scene, and establishing a mathematical model for calculating constellation network topological relation in real time; the dynamic change of the satellite seat network topological relation during the satellite in-orbit operation is studied in depth, and the problem of optimizing and designing the number of beams required by minimizing LEO satellite constellation under the condition of meeting the constraint of system communication requirements is solved; the optimization problem is further converted into the sum of the number of active beams which can be provided by each satellite on the basis of the closable beam forming design, and a dynamic user switch management method is further provided. The invention can dynamically adjust the beam switch according to the link topological relation and the number of users in the constellation network, effectively reduces the energy consumption of the system and further improves the utilization rate of beam resources.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or N embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "N" means at least two, for example, two, three, etc., unless specifically defined otherwise.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and additional implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order from that shown or discussed, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present invention.
Claims (6)
1. The dynamic beam switch management method in the low orbit satellite mobile communication scene is characterized by comprising the following steps:
designing a user beam which can be dynamically closed and takes a user as a center;
constructing a mathematical model suitable for a digital multi-beam low-orbit satellite mobile communication scene and used for calculating the constellation network topological relation in real time;
establishing an optimal design problem of minimizing the number of beams required by a low-orbit satellite constellation under the constraint of system communication requirements;
and carrying out a dynamic user beam switch management method based on the optimal design problem.
2. The method of claim 1, wherein designing a user beam that is dynamically off and user-centric comprises:
based on the downlink transmission scene of the low-orbit satellite, the phased array of the low-orbit satellite is provided with a dynamic multi-beam digital beam shaper and is N at the same time K A single antenna user provides communication services, and a low orbit satellite is provided with a uniform plane array, which is formed by N T ＝M x M y An antenna array element, wherein M x and My The number of antenna elements on the x and y axes, respectively;
at time t and frequency f, the channel model from the low-orbit satellite to the kth user can be modeled as:
wherein ,vsat Representing doppler shift due to the fast movement of the low orbit satellite,represents the minimum path delay, g, of the kth user k (t, f) represents the firstDownlink channel gains of k users including large-scale fading and gain information under different paths, +.>Array response vector, N, for a uniform planar array of satellites T The number of the antenna array elements;
defining s_ { k } as data transmitted from the low-orbit satellite to the kth user, the received signal of the kth user is expressed as wherein ,/>Mean value zero, variance ++>Additive white gaussian noise of +.>DBF vector, N, representing kth user RF The number of the radio frequency links;
establishing a transmission model of an all-digital phased array antenna equipped satellite communication system, denoted as y= HWs +n, whereinFor a channel matrix>In order to pre-code the matrix,representing AWGN vectors, each element a obeys independently +.>Mean zero variance +.>Is a complex Gaussian distribution of->w k Satisfy->Wherein P is the power constraint, and the total power transmitted by the system is recorded as P total ；
The satellite side performs switching operation on satellite carrier beams through beam allocation instructions of a ground station on the basis of a dynamic all-digital multi-beam forming architecture, and a power allocation factor is determined by an input channel matrix H and dimensions thereof, wherein the H dimensions represent the number N of current satellite opening beams Bopen The H dimension does not exceed the number N of beams available to the satellite B The baseband digital beamforming matrix W may be obtained by beam design with the precoding matrix W as the beamforming matrix input D And a power division factor, thereby adjusting the power divider to make the port power constraint of the system corresponding to the beam to be turned off be 0, and the port total power constraint of the beam to be turned on beTo turn on and off the selected set of beams.
3. The method of claim 2, wherein constructing a mathematical model for a digital multi-beam low orbit satellite mobile communications scenario for calculating constellation network topology in real time comprises:
defining a satellite plane local coordinate system: the origin of coordinates O is defined as the mass center of the satellite, the +Z axis is defined as the direction from the satellite to the earth's center of earth, the +X axis is defined as the moving direction, and the +Y axis direction is determined by the principle of a right-hand coordinate system;
let the number of satellites in the low orbit satellite constellation of the current communication system be N S The satellite in the constellation is s i ，i＝1,2,...,N S Satellite recordingAggregationThe number of users is N K User u j ，j＝1,2,...,N K Record user setThe number of beams of each satellite is N B The total number of the beams of the system is N B,tot ＝N S N B Beam set->In beam set +.>Is to allocate a beam for each user terminal>And the other coverage beams are turned off. Set satellite s i The user set of the service is->User u j Communication satellite set->For beam b ij In other words, under the satellite local coordinate system, the spatial orientation is definedTo indicate the beam pointing, each user is assigned a beam and the beam center is pointed to the user according to dynamic multi-beam digital beamforming techniques, when beam b ij The served user is u k When its spatial orientation is converted into +.>
4. A method according to claim 3, wherein establishing an optimal design problem for minimizing the number of beams required for a low-orbit satellite constellation to meet system communication requirement constraints comprises:
definition of user terminal-satellite related coverage factor c i,k Representing the kth user terminal u k Whether or not at the ith satellite s i Within the communication service range of c i,k The expression is:
defining a beam state factor a ij To characterize the beam in an active or off state, a ij The calculation formula is as follows:
establishing an optimization problem of beam switch management:
establishing constraint conditions: a) Ensuring coverage of the service area; b) The coverage mode of providing user beam communication by the satellite is a service mechanism taking users as centers, and a beam is distributed to each user to realize beam staring; the expression is as follows:
5. the method of claim 4, wherein the dynamic user beam switch management method based on the optimization design problem comprises:
definition of satellites s i Serving beam-user terminal pairing set as
By realizing that each user distributes a beam according to the design result of the user beam and the beam center points to the user terminal, the optimization goal of minimizing the beam quantity can be realized by reasonably selecting a proper satellite for each user to provide a user service beam, and the satellites s are defined i Serving beam-user terminal pairing set asThe optimization problem can be translated into:
wherein ,representing the set of beam-user pairs +.>Of elements, i.e. satellites s i The number of user beams provided;
based on the optimization design problem, the satellite load and satellite selection criteria are considered to dynamically manage the user beam switch.
6. The method of claim 1, wherein dynamically managing user beam switching based on optimization design considerations, taking into account satellite loading and satellite selection criteria, comprises:
initializing the number N of user terminals K Number of satellites N S Number of beams N provided by each satellite B Satellite cluster covered by user
Determining the position information of each satellite and the user terminal at the current moment;
determining satellites in a systemIs +.>The coverage relation between them to determine the coverage factor c i,k To obtain the value of each user u k Covered satellite set +.>
Statistical aggregation clusterIs>The number of elements of (2) are ordered from small to large, and the ordered aggregation cluster +.>
Per cluster setAre>Order, determining the preamble user u k ；
In communicable satellites according to the principle of least-priority of channel lossSatellite s with minimum channel fading i ；
Judging satellite s i Set of provided beam-user pairsThe number of elements is less than or equal to N B If smaller than, user u k Selecting the satellite and assigning a beam thereto; otherwise, satellite s i Is full, other satellites within communication range need to be selected, return per cluster +.>Are>Order, determining the preamble user u k A step of;
judging whether users in the system have all selected completely, if not, clustering the setAre>The next user terminal u corresponding in sequence k′ Satellite selection and beam allocation are performed, i.e. let k=k', return per cluster +.>Are>Order, determining the preamble user u k A step of; otherwise, jumping out of the circulation;
output aggregation cluster
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