CN110445528B - Satellite cross-gateway station feeder link switching method based on user switching limitation and unloading - Google Patents
Satellite cross-gateway station feeder link switching method based on user switching limitation and unloading Download PDFInfo
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- CN110445528B CN110445528B CN201910675491.2A CN201910675491A CN110445528B CN 110445528 B CN110445528 B CN 110445528B CN 201910675491 A CN201910675491 A CN 201910675491A CN 110445528 B CN110445528 B CN 110445528B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18513—Transmission in a satellite or space-based system
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18519—Operations control, administration or maintenance
Abstract
The invention discloses a satellite cross-gateway station feeder link switching method based on user switching limitation and unloading, belonging to the field of satellite communication; the working principle is as follows: calculating the orbit position of satellite S switching by taking the minimum number of users in a single satellite coverage area in the satellite S coverage area as a target; pre-estimating a geographical area covered by a satellite S when a feed link of a gateway station is switched and a multi-satellite coverage area in the geographical area; limiting users receiving other satellite services in a multi-satellite coverage area to switch to a satellite S; unloading users which are simultaneously covered by other satellites in the multi-satellite coverage area and receive the satellite S service to other satellites; when the satellite S switches the gateway stations, the users to which the satellite S belongs switch the gateway stations at the same time; and after the satellite S completes the cross-gateway station feeder link switching, the switching limitation and unloading strategy for the satellite S is cancelled. The method can minimize the number of users who follow the switching of the satellite cross-gateway station feeder link, and improve the overall experience of the users when the satellite cross-gateway station feeder link is switched.
Description
Technical Field
The invention belongs to the field of low-earth-orbit satellite communication, and particularly relates to a satellite cross-gateway station feeder link switching method based on user switching limitation and unloading.
Background
With the rapid development of low-orbit satellite constellations, more and more low-orbit satellite systems are being constructed. The problem of satellite cross-gateway feeder link switching, which is unique to low earth orbit satellite systems, has become an important issue for system solution research. In particular, in a low-orbit satellite system with a transparent satellite forwarding function, the satellite only plays a role of covering a main use, and the satellite must always establish a feeder link connection with a gateway station in order to serve a user terminal in a coverage area. When the low earth orbit satellite moves at high speed to cover the gateway station, the feeder link is switched from the source gateway station to the target gateway station, so that the user terminals receiving the satellite service are switched collectively. Large-scale users initiate switching in a short time, congestion is generated, and switching users are seriously lost.
At present, for the switching of a transparent forwarding satellite feeder link, research is mostly focused on how to select a new satellite for connection at a gateway station, and strategies based on load balancing, longest service time, maximum matching of bipartite graphs and the like appear. However, research is weak for the problem of switching a large number of user terminals due to the satellite feeder link switching.
Aiming at the problem of collective switching of a large number of user terminals caused by switching of satellite feeder links, a set of effective solutions needs to be further provided, the number of users who follow the satellite to switch across the gateway station is reduced, the call drop rate of user switching is reduced, and the overall experience of system users under the condition that the satellite switches across the gateway station feeder links is improved.
Disclosure of Invention
In order to solve the problem that a large number of user terminals are switched due to satellite feeder link switching, the invention provides a satellite cross-gateway station feeder link switching method based on user switching limitation and unloading.
The invention provides a satellite cross-gateway station feeder link switching method based on user switching limitation and unloading, as shown in figure 1, the realization process of the method comprises the following steps: calculating the cross-gateway station feeder link switching position meeting the optimization condition 1, pre-estimating the ground coverage area and the multi-satellite coverage area 2 when the satellite S is switched across the gateway station feeder link, limiting user switching 3, unloading the user 4, switching the single-satellite coverage area user to the cross-gateway station following the satellite 5, and canceling the switching limitation and unloading strategy for the satellite S6.
The technical scheme of the invention is a satellite cross-gateway station feeder link switching method based on user switching limitation and unloading, which comprises the following steps:
step 1: in the overlapping coverage area of a source gateway station and a target gateway station, the number of users in a single satellite coverage area in the coverage area of a satellite S is minimized as a target, and the orbit position of the switching of the satellite S across a gateway station feeder link is calculated based on ephemeris, the positions of the source gateway station and the target gateway station and the user distribution rate;
step 2: the source gateway station calculates the ground coverage area of the satellite S at the switching position of the feed link of the cross gateway station in advance, and calculates the multi-satellite coverage area in the coverage area;
and step 3: user handover restriction
Switching restriction is performed for users receiving other satellite services in the multi-satellite coverage area in the step 2, and the users are switched to the satellite S when the users are only covered by the satellite S;
and 4, step 4: user offload policy
Aiming at the situation that the user receiving the satellite S service in the multi-satellite coverage area in the step 2 is simultaneously covered by the satellite S and other satellites, other satellites are selected for switching, and the user is unloaded to other satellites;
and 5: the satellite S is switched across the gateway station feeder link, and users in a single satellite coverage area covered by the satellite S collectively follow the satellite S to be switched across the gateway station to a target gateway station;
step 6: and after the satellite S completes the cross-gateway station feeder link switching, canceling the user switching limitation and the user unloading strategy aiming at the satellite S.
Further, the user distribution rate in step 1 refers to the number of users in a unit coverage area that are in a connection state with the gateway station, and is obtained by counting the user conditions of the banded regions covered by all satellites on the orbit plane where the satellite S is located by the gateway station, and the data is updated periodically, and the user distribution rates in different geographic regions are different in different time periods.
Further, the method for calculating the switching position of the satellite S in step 1 includes:
step 1.1: determining an orbit position interval which can be covered by the source gateway station and the target gateway station simultaneously by the satellite S according to the positions of the source gateway station and the target gateway station based on the ephemeris;
step 1.2: moving the area covered by the satellite S in a certain step length on the interval, and calculating the number of users in the multi-satellite coverage area in the satellite S coverage area each time;
step 1.3: and selecting the orbit position of the corresponding satellite S when the number of the users is the minimum, namely the orbit position of the satellite S for cross-gateway station feeder link switching.
Further, the switching of the orbit position of the satellite S across the gateway station feeder link in step 1 has the following characteristics: the number of users in a single satellite coverage area of the satellite S under the satellite coverage area at that location is minimized throughout the sliding of the satellite S through the overlapping coverage areas of the source and target gateway stations.
Further, the users in step 4 are unloaded, as the satellite moves, the users receiving the service of the satellite S in step 4 are gradually unloaded to other satellites, and the users receiving the service of the satellite S in the multi-satellite coverage area in step 2 are gradually reduced until all the users in the area are unloaded.
Further, in step 4, the user unloads and selects other satellites, and the satellite selection strategy is to preferentially select the satellites belonging to the same gateway station as the satellite S from the other satellites. And selecting the satellite of the gateway station which belongs to the same gateway station as the satellite S, and executing inter-satellite switching in the gateway station, wherein the switching time delay is shorter than that of cross-gateway station switching, and the user experience is better.
Compared with the prior art, the satellite cross-gateway station feeder link switching method based on user switching limitation and unloading has the following beneficial effects:
the invention minimizes the number of users switched along with the satellite cross-gateway station feeder link by calculating the orbit position corresponding to the minimum number of users in the single satellite coverage area in the under-satellite coverage area as the switching point of the satellite cross-gateway station feeder link.
The invention implements switching limitation and user unloading aiming at different types of users in a multi-satellite coverage area in the under-satellite coverage area, effectively reduces the number of users collectively switched to the target gateway station along with the satellite, relieves the switching pressure and reduces the call drop rate of the users.
The method effectively solves the problem of user switching under the satellite when the satellite crosses the gateway station, is suitable for low-orbit satellite systems with various constellation configurations, and has engineering application value.
Drawings
Fig. 1 is a schematic diagram of a satellite cross-gateway feeder link handoff method based on subscriber handoff restriction and offloading in accordance with the present invention.
Figure 2 is a schematic diagram of a subscriber handoff restriction and offloading based satellite cross-gateway feeder link handoff implementation of the present invention.
Fig. 3 is a schematic diagram illustrating the minimization of the coverage area of a single satellite under the satellite S in the polar-orbit constellation.
Fig. 4 is a schematic diagram of an implementation case user switch restriction and offloading process.
Detailed Description
The invention is further described with reference to the following figures and examples.
The invention provides a satellite cross-gateway station feeder link switching method based on user switching limitation and unloading, as shown in figure 1, the method comprises the following components: calculating the cross-gateway station feeder link switching position meeting the optimization condition 1, pre-estimating the ground coverage area and the multi-satellite coverage area 2 when the satellite S is switched across the gateway station feeder link, limiting user switching 3, unloading the user 4, switching the single-satellite coverage area user to the cross-gateway station following the satellite 5, and canceling the switching limitation and unloading strategy for the satellite S6.
For explaining the method of switching the feeder link of the satellite across the gateway station based on the user switching limitation and unloading, taking the polar orbit constellation and the uniform distribution of users as an example, refer to fig. 3 and 4. The specific processing steps (see fig. 2) are as follows:
step 1: and in the overlapping coverage area of the source gateway station and the target gateway station, calculating the orbit position corresponding to the minimum number of users in the coverage area of the satellite S in the single satellite based on the ephemeris of the satellite S, the position of the source gateway station and the position of the target gateway station. Due to the uniform distribution of users, only the orbit position corresponding to the minimum area of the single satellite coverage area in the satellite S coverage area needs to be calculated. Since the constellation is polar orbit, the area of the overlapping region covered by the satellite with the same orbital plane is not changed, and as the latitude increases, the area of the overlapping region covered by the satellite with the different orbital plane becomes larger, and the area of the corresponding single satellite coverage region becomes smaller, as shown in fig. 3. Thus, the optimal orbital position for switching of the satellite S across the gateway station feeder link is a high latitude position, such as the O' position in fig. 3, of the overlapping coverage area of the source and target gateway stations.
Step 2: when the satellite S reaches the feeder link switching position, the coverage area of the satellite S (the portion of the ellipse of the dotted line in fig. 4) and the area overlapping with the adjacent satellite # 1, the satellite # 2, the satellite # 3, and the satellite #4 (the outer area of the "mouth" type in fig. 4) are estimated in advance by combining the ephemeris and the switching position of the satellite # 1, the satellite # 2, the satellite # 3, and the satellite # 4, as shown in fig. 4.
And step 3: and (3) aiming at the overlapping area in the step (2), simultaneously executing user switching limitation and user unloading, wherein in the satellite moving process, the user switched to the satellite S through the user switching limitation also needs to participate in the user unloading process. The user switching restriction is step 4 to step 6, and the user unloading is step 7 to step 9.
And 4, step 4: users in the multi-satellite coverage area that are served by other satellites ( satellites # 1, 2, 3, 4) remain served by the current satellite;
and 5: judging whether the user terminal is about to leave the coverage of the service satellite, if so, executing step 6; otherwise, returning to the step 4;
step 6: judging whether the user terminal is to be covered by the satellite S only or not, and executing a step 7 if the user terminal is to be covered by the satellite S only; otherwise, returning to the step 4;
as in terminal B of fig. 4, terminal B is served by satellite # 3, i.e. is about to leave the coverage of satellite # 3, and is about to be covered by satellite S only, and is switched from satellite # 3 to satellite S; the terminal C receives the satellite # 3 service, is covered by the satellite S, but does not leave the coverage of the satellite # 3, and therefore continues to receive the satellite # 3 service.
And 7: a user receiving satellite S service in a multi-satellite coverage area keeps receiving current satellite service;
and 8: judging whether the user is in the coverage area of other satellites ( satellites # 1, 2, 3 and 4), if so, executing the step 9, otherwise, returning to the step 7;
and step 9: judging whether any satellite belongs to the current gateway station or not, if so, selecting the satellite belonging to the current gateway station as a target satellite, and executing cross-satellite switching in the gateway station; otherwise, selecting one satellite as a target satellite, and executing cross-gateway and cross-satellite switching;
as shown in fig. 4, terminal a receives service from satellite S and is in the coverage area of satellites S, #1, #4, where satellite # 1 belongs to the source gateway station and satellite # 4 belongs to the target gateway station, so terminal a preferentially selects satellite # 1 for offloading and switches from satellite S to satellite # 1 within the gateway station.
Step 10: judging whether the satellite S reaches the position of switching the orbit of the feed link of the cross gateway station, if so, executing a step 11; otherwise, returning to the step 3;
step 11: the user terminal in the single satellite coverage area in the step 2 is switched to a target gateway station together with the satellite S;
step 12: the handoff restrictions and offloading policies for the particular coverage area of satellite S are removed.
The above detailed description of the embodiments of the present invention, and the detailed description of the embodiments of the present invention used herein, is merely intended to facilitate the understanding of the methods and apparatuses of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (5)
1. A method for subscriber handoff restriction and offloading based satellite cross-gateway feeder link handoff, the method comprising:
step 1: in the overlapping coverage area of a source gateway station and a target gateway station, the number of users in the coverage area of a single satellite in the coverage area of the satellite (S) is minimized as a target, and the orbit position of the switching of the satellite (S) across the gateway station feeder link is calculated based on ephemeris, the positions of the source gateway station and the target gateway station and the user distribution rate; the user distribution rate refers to the number of users in a unit coverage area which are kept in a connection state with a gateway station, the user conditions of banded regions covered by all satellites on an orbital plane where the satellites (S) are located are counted by the gateway station, data are updated regularly, and the user distribution rates of different geographical regions in different time periods are different;
step 2: the source gateway station pre-calculates the ground coverage area of the satellite (S) at the switching position of the feeder link of the cross gateway station and calculates the multi-satellite coverage area in the coverage area;
and step 3: user handover restriction
Performing switching limitation aiming at users receiving other satellite services in the multi-satellite coverage area in the step 2, wherein the users are switched to the satellite (S) when being only covered by the satellite (S);
and 4, step 4: user offload policy
Aiming at the situation that the user receiving the satellite (S) service in the multi-satellite coverage area in the step 2 is simultaneously covered by the satellite (S) and other satellites, other satellites are selected for switching, and the user is unloaded to other satellites;
and 5: the satellite (S) is switched to a gateway station cross feeder link, and users in a single satellite coverage area covered by the satellite (S) collectively follow the satellite (S) to be switched to a target gateway station in a gateway station cross mode;
step 6: and after the satellite (S) completes the cross-gateway station feeder link switching, the user switching limitation and the user unloading strategy aiming at the satellite (S) are cancelled.
2. The method according to claim 1, wherein the satellite (S) switching orbit position across the gateway station feeder link in step 1 has the following characteristics: the number of users in a single satellite coverage area of the satellite (S) under the satellite coverage area of that location is minimized throughout the sliding of the satellite (S) through the overlapping coverage areas of the source and target gateway stations.
3. The method according to claim 1, wherein in step 4, users are unloaded, and as the satellite moves, users receiving services from the satellite (S) in step 4 are gradually unloaded to other satellites, and users receiving services from the satellite (S) in the coverage area of the multi-satellite are gradually reduced in step 2 until all users in the coverage area are unloaded.
4. A method for switching satellite cross-gateway station feeder link based on user switching restriction and offloading as claimed in claim 1, characterized in that in said step 4 the user offloads the selection of other satellites, the strategy of satellite selection is to preferentially select among the other satellites the satellite belonging to the same gateway station as the satellite (S).
5. The method for switching the satellite cross-gateway feeder link based on the subscriber switching restriction and unloading as claimed in claim 1, wherein the satellite (S) switching position in the step 1 is calculated by:
step 1.1: determining an orbit position interval in which the satellite (S) can be simultaneously covered by the source gateway station and the target gateway station according to the positions based on the ephemeris and the positions of the source gateway station and the target gateway station;
step 1.2: moving the area covered by the satellite (S) in a certain step length on the interval, and calculating the number of users in the multi-satellite coverage area in the coverage area of the satellite (S) each time;
step 1.3: and selecting the orbit position where the corresponding satellite (S) is located when the number of the users is the minimum, namely the orbit position where the satellite (S) is switched across the gateway station feeder link.
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| CN113099495B (en) * | 2020-01-09 | 2022-04-15 | 大唐移动通信设备有限公司 | Gateway station conversion method, device, terminal and gateway station |
| CN111262616B (en) * | 2020-01-15 | 2020-11-13 | 广州爱浦路网络技术有限公司 | User data switching device and switching method for low-orbit satellite gateway station |
| CN113260005B (en) * | 2020-02-13 | 2022-07-29 | 华为技术有限公司 | Gateway station switching method and device |
| CN111314981A (en) * | 2020-02-20 | 2020-06-19 | 北京华力创通科技股份有限公司 | Terminal reselection method and device for feeder link switching |
| CN113365315B (en) * | 2020-03-03 | 2023-06-06 | 华为技术有限公司 | Gateway station switching method and device |
| CN113543149B (en) * | 2020-04-17 | 2023-03-28 | 中国电信股份有限公司 | Control method, device, system and storage medium for establishing feeder link |
| WO2022061664A1 (en) * | 2020-09-24 | 2022-03-31 | Oppo广东移动通信有限公司 | Transmission control method and apparatus, device, and storage medium |
| CN112671448A (en) * | 2020-12-09 | 2021-04-16 | 中国电子科技集团公司第五十四研究所 | Cross-satellite switching method for feeder link in low-earth-orbit satellite mobile communication system |
| CN113472424B (en) * | 2021-06-30 | 2023-03-28 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | Different-frequency measurement switching device for ephemeris-assisted flexible switch multi-satellite coverage area |
| CN113489530B (en) * | 2021-07-26 | 2022-08-19 | 中电防务科技有限公司 | Method for synchronously switching feeder links in low-earth-orbit constellation satellite communication system |
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