A measurement control method and device applied to a satellite network

Abstract

The application provides a measurement control method and device applied to a satellite network, the method comprising the following steps: S1, a base station predicts all beams theoretically covering the terminal and a target beam; S2, when a current position of the terminal exceeds a distance threshold value from a position reported for the first time, the terminal enters step S5, otherwise, the terminal enters step S3; S3, when the terminal is close to an edge of the target beam, the terminal performs conventional measurement and reports a measurement report according to the conventional measurement; S4, the base station performs coverage verification, if the coverage verification is passed, the base station enters step S7, otherwise, the base station enters step S5; S5, the terminal reports position information again, and the base station performs switching prediction again; S6, after a set time from the reporting of the position information, the terminal performs burst measurement and reports a measurement report; S7, the base station determines a switching decision and performs coverage verification, if the coverage verification is passed, the base station executes the switching decision, otherwise, the base station enters step S5. The application is suitable for measurement of the satellite network, and the measurement effectiveness is high.

Description

Technical Field

[0001] This invention relates to a measurement and control method and apparatus for use in satellite networks. Background Technology

[0002] In communication networks, the measurement of beam signal strength by the terminal is mainly configured by the base station through control signaling. The base station's control over the measurement is mainly divided into three parts: measurement switch (determining when the measurement control message is sent), measurement configuration (determining how the terminal measures), and measurement reporting (determining when the measurement report is reported).

[0003] Terminal measurements are primarily performed to select appropriate target cells and beams during access or handover. In terrestrial networks, due to the fixed locations of base stations, small cell coverage areas, and complex terminal mobility, terminal access and handover are mainly determined by the terminal's own mobility. However, in satellite network systems, the satellites responsible for terminal access typically move much faster than the terminals themselves, to the point that terminal mobility is negligible relative to satellite mobility for a short period. This makes satellite mobility the primary factor determining terminal handover in satellite networks. This fundamental difference means that existing measurement and control methods suitable for terrestrial applications are not well-suited for satellite networks. For example, in terrestrial networks, the complex mobility of terminals makes it difficult for base stations to determine when terminals should upload measurement reports. Therefore, the reporting time is usually determined by the terminal itself, requiring the terminal to trigger the upload of measurement reports in potential handover scenarios. This leads to terminals uploading measurement reports at unnecessary times, wasting link resources. Therefore, a measurement and control method more suitable for satellites is needed. Summary of the Invention

[0004] The purpose of this invention is to propose a measurement and control method and device for satellite networks, which is suitable for satellite network measurement, has high measurement effectiveness, and can also avoid wasting link resources.

[0005] This invention is achieved through the following technical solution:

[0006] A measurement and control method for satellite networks includes the following steps:

[0007] Step S1: The base station performs handover prediction based on the location information initially reported by the terminal, in order to predict all beams that theoretically cover the terminal and the target beam for handover.

[0008] Step S2: When the distance between the current location and the location previously reported to the base station exceeds the distance threshold due to the terminal's own movement, proceed to step S5; otherwise, proceed to step S3.

[0009] Step S3: When the terminal approaches the edge of the target beam, the base station sends a measurement control message based on the handover prediction result in step S1. The terminal performs routine measurements based on the measurement control message and periodically reports the measurement report to the base station.

[0010] Step S4: The base station analyzes all beams that actually cover the terminal based on the measurement report in step S3, and verifies the coverage of the prediction results obtained in step S1. If the verification is successful, proceed to step S7; otherwise, proceed to step S5.

[0011] Step S5: The terminal re-reports its location information to the base station. The base station then performs a handover prediction based on the location information to predict all beams that theoretically cover the terminal.

[0012] Step S6: After a set time since the location information was re-reported, the terminal performs a burst measurement and uploads the measurement report to the base station;

[0013] Step S7: The base station determines the handover decision based on the latest handover prediction results and the latest measurement report from the terminal, and performs coverage verification. If the verification passes, the handover decision is executed; otherwise, proceed to step S5.

[0014] The coverage verification involves comparing the theoretical coverage of the terminal with the actual coverage of the terminal. If they are consistent, the verification passes; otherwise, the verification fails.

[0015] Furthermore, in step S6, the set time is the minimum measurement cycle that the satellite network can accept.

[0016] Furthermore, the measurement report includes the beam reference signal received power.

[0017] Furthermore, in step S1, the handover prediction specifically involves: the base station performing orbit prediction based on ephemeris to analyze the satellite's motion trajectory over a period of time, and based on the motion trajectory, the location of the base station, and the location of the terminal, predicting all beams that theoretically cover the terminal and the target beam for handover.

[0018] Furthermore, in step S3, the measurement control message includes three parts: measurement switch, measurement configuration, and measurement reporting. The measurement switch indicates when the terminal starts neighbor cell measurement, the measurement configuration indicates the measurement object and measurement cycle of the terminal, and the measurement reporting indicates when the terminal reports the measurement report. The neighbor cell refers to the adjacent beam of the target beam, which is determined by the base station. The measurement cycle setting needs to ensure that the terminal can perform at least two neighbor cell measurements during the period from approaching the target beam to starting the handover, so as to achieve the purpose of assisting the handover.

[0019] Furthermore, both the conventional and burst measurements are at the same frequency or different frequency beam level.

[0020] Furthermore, if the received power of the beam reference signal in the measurement report is greater than the set power threshold, it is considered that the beam actually covers the terminal.

[0021] Furthermore, the distance threshold is related to the beam radius of the current service terminal.

[0022] Furthermore, in step S6, after the set time, if the base station shuts down the transmission of measurement control messages, the terminal performs burst measurement according to the measurement control message previously sent by the base station; otherwise, the terminal performs burst measurement according to the current measurement control message.

[0023] This invention is also achieved through the following technical solutions:

[0024] A measurement and control device for satellite networks includes a base station, a transceiver unit, and a terminal. The base station includes a processor, which is connected to the terminal via the transceiver unit. The processor includes:

[0025] A module that predicts handover based on location information reported by the terminal;

[0026] A module that sends measurement and control information to the terminal when the terminal is near the edge of the target beam;

[0027] The module analyzes all beams that actually cover the terminal based on the measurement report reported by the terminal and performs coverage verification.

[0028] A module that determines handover decisions based on the latest handover prediction results and the latest measurement reports from the terminal, and performs coverage verification;

[0029] The terminal is used to perform routine measurements and burst measurements based on measurement and control information, and to upload measurement reports to the processor.

[0030] The present invention has the following beneficial effects:

[0031] 1. In this invention, the base station first performs handover prediction based on the initial location information reported by the terminal, and then performs coverage verification based on the terminal's regular measurement report. If the verification passes, a handover decision is executed. If the verification fails, the terminal re-reports its location information to the base station, and the base station performs handover prediction again. After a period of time following the re-reporting of location information, the terminal performs burst measurements. The base station performs coverage verification again based on the burst measurement report. If the verification passes, a handover decision is executed; otherwise, the process of re-reporting location information continues. If the coverage verification fails, the terminal is required to re-upload its location information. This avoids handover prediction anomalies caused by inaccurate terminal location reporting or inaccurate base station prediction results, thereby improving the effectiveness of the measurement and making this invention more suitable for satellite network measurements. The terminal performs measurements based on the measurement control messages issued by the base station and uploads measurement reports at specific times. That is, the terminal's measurement actions are controlled by the base station. This avoids unnecessary measurements and the waste of link resources caused by the terminal uploading measurement reports at unnecessary times, further improving the adaptability of this invention to satellite network measurements. Attached Figure Description

[0032] The present invention will now be described in further detail with reference to the accompanying drawings.

[0033] Figure 1 This is a flowchart of the present invention.

[0034] Figure 2 This is a schematic diagram of the neighboring cell beam of the present invention.

[0035] Figure 3 This is a schematic diagram of the 52-beam narrowband single-satellite deployment of the present invention. Detailed Implementation

[0036] In this embodiment, the reset satellite in the satellite network is a narrowband single satellite, and its 52-beam deployment is as follows: Figure 3 As shown, the entire satellite's Earth coverage range is ±56°, with the 4th nadir beams ranging from 0 to 32°, the second ring beams from 32° to 48°, and the outer ring beams from 48° to 56°, with north at the top. The beams on each ring are uniformly deployed. The handover prediction uses the existing orbit extrapolation method based on SGP4 and the nadir point position calculation method based on projection. The terminal's trajectory relative to the satellite is predicted based on the terminal's position and the satellite's moving speed obtained from SGP4.

[0037] like Figure 1 As shown, the measurement and control method applied to satellite networks includes the following steps:

[0038] Step S1: The base station performs handover prediction based on the location information initially reported by the terminal, to predict all beams that theoretically cover the terminal and the target beam for handover, specifically including:

[0039] When any terminal accesses a base station, the terminal reports its own location information. The base station performs orbit prediction based on ephemeris to analyze the satellite's motion trajectory over a period of time. Based on this motion trajectory, the location of the base station, and the location of the terminal, it predicts all beams that theoretically cover the terminal, as well as the target beam and target satellite for switching. If the target satellite is the serving satellite itself, an intra-satellite beam switching will occur. If the target satellite is a non-serving satellite, an inter-satellite beam switching will occur. For both switching scenarios, the satellite needs to be measured and reconfigured to assist in the terminal switching process.

[0040] Step S2: When the distance between the current location and the location previously reported to the base station exceeds the distance threshold due to the terminal's own movement, proceed to step S5; otherwise, proceed to step S3. The distance threshold is related to the source beam radius, and the specific relationship between the two is in the prior art. The source beam is the beam of the current serving terminal.

[0041] Step S3: When the terminal is close to the edge of the target beam, the base station sends a measurement control message according to the handover prediction result in step S1. The terminal performs routine measurements according to the measurement control message and reports the measurement report to the base station. The measurement report includes the measured beam index and its corresponding channel quality measurement values, such as the beam reference signal received power.

[0042] The measurement control message includes three parts: measurement switch, measurement configuration, and measurement reporting. The measurement switch indicates when the terminal starts neighbor cell measurement, the measurement configuration indicates the measurement object and measurement cycle of the terminal, and the measurement reporting indicates when the terminal reports the measurement report. The measurement process is also summarized according to different situations.

[0043] exist Figure 2 In the diagram, the black dot represents the terminal's current location, beam 0 represents the terminal's current serving beam (i.e., the source beam), the black arrow represents the predicted relative motion trajectory of the terminal over the next period of time, beam 1 represents the target beam, and beams 2-6 represent the neighboring beams to be considered, i.e., the neighboring cells.

[0044] The measurement switch section is designed to activate the measurement of adjacent beams when the terminal is about to enter the beam overlap area (i.e., near the edge of the target beam).

[0045] The measurement configuration section is as follows:

[0046] Measurement object configuration: If the current terminal is in the inner beam of the satellite, the base station can obtain the adjacent beams of the terminal by looking up a table. If the terminal is currently in the outer beam of the satellite, the base station needs to analyze whether the next step is an inter-satellite handover and predict the adjacent beams of the terminal when the handover is about to take place. This process is the existing technology, but at this time the measurement object is only the predicted target beam and does not include other adjacent beams.

[0047] Measurement cycle: The measurement cycle is configured according to the predicted time when the terminal is in the overlapping area of ​​adjacent beams, so that the terminal can perform at least two neighboring cell measurements during the period from approaching the target beam to the start of handover, in order to achieve the purpose of assisting handover and coverage verification.

[0048] Measurement reporting section: During routine measurement, the measurement reporting cycle is set according to the predicted time when the terminal is in the overlapping area of ​​adjacent beams, so that the number of measurement reports reported by the terminal before the predicted start time of handover is sufficient for handover based on measurement values ​​and verification of prediction results.

[0049] Routine measurements include same-frequency or different-frequency beam-level measurements. For different-frequency measurements, the measurement period should be set to allow the receiver sufficient time to adjust the frequency band and perform the measurement. During this period, the terminal's normal data transmission and reception will be affected. Therefore, when different-frequency measurements are involved, the measurement period should be as long as possible to reduce the number of measurements and minimize the impact on the terminal's normal data transmission and reception.

[0050] Step S4: The base station analyzes all beams that actually cover the terminal based on the measurement report in step S3, and verifies the coverage of the prediction results obtained in step S1. If the verification is successful, proceed to step S7; otherwise, proceed to step S5.

[0051] The coverage verification involves comparing the theoretical coverage of the terminal with the actual coverage of the terminal. If they are consistent, the verification passes; otherwise, the verification fails.

[0052] After receiving the measurement report, the base station parses the signal strength of each beam (the signal strength is determined by the received power of the beam reference signal). When the received power of the beam reference signal is greater than the set power threshold, it is considered that the beam actually covers the terminal. Thus, all beams that actually cover the terminal are obtained according to the measurement report. Step S5: The terminal updates its own location information through the positioning system and re-reports the location information to the base station. The base station performs handover prediction again based on the location information to predict all beams that theoretically cover the terminal. The handover prediction process is the same as described in step S1.

[0053] Step S6: After a set time since the location information was re-reported, the terminal performs a burst measurement and uploads the measurement report to the base station;

[0054] Specifically, if the terminal receives a request to re-report its location at time t0, it immediately reports its own location information without the base station needing to perform new measurement configurations. It then spontaneously performs measurements and reports a measurement report at time t1. The interval between time t1 and time t0 is the minimum measurement cycle that the satellite network can accept.

[0055] At time t0, if the base station disables the transmission of measurement control messages, the terminal performs burst measurement based on the measurement control message previously transmitted by the base station; otherwise, the terminal performs burst measurement based on the current measurement control message.

[0056] Burst measurements include same-frequency or different-frequency beam-level measurements; they are also divided into three parts: measurement switching, measurement configuration, and measurement reporting.

[0057] Measurement switch section: After the terminal re-uploads the location information, the base station performs prediction again and uses the new prediction result as a reference to control the terminal to start neighbor cell measurement;

[0058] Measurement objects: In addition to the target beam, other nearby beams are also included;

[0059] Measurement period: Set to a single time of the target beam synchronization signal broadcast period, which is short enough to respond quickly to this anomaly.

[0060] Measurement report submission section: The measurement reporting cycle should be as short as possible so that the base station can verify the prediction results after the location update in a short time;

[0061] Step S7: The base station determines the handover decision based on the latest handover prediction results and the latest measurement report from the terminal, and performs coverage verification. If the verification is successful, the handover decision is executed; otherwise, proceed to step S5.

[0062] Corresponding to the above measurement and control method, a measurement and control device applied to a satellite network includes a base station, a transceiver unit, and a terminal. The base station includes a processor, which is connected to the terminal through the transceiver unit. The processor includes:

[0063] A module that predicts handover based on location information reported by the terminal;

[0064] A module that sends measurement and control information to the terminal when the terminal is near the edge of the target beam;

[0065] The module analyzes all beams that actually cover the terminal based on the measurement report reported by the terminal and performs coverage verification.

[0066] A module that determines handover decisions based on the latest handover prediction results and the latest measurement reports from the terminal, and performs coverage verification;

[0067] The terminal is used to perform routine measurements and burst measurements based on measurement and control information, and to upload measurement reports to the processor.

[0068] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent application and the contents of the specification of the present invention should still fall within the scope of the patent of the present invention.

Claims

1. A measurement and control method applied to satellite networks, characterized in that: Includes the following steps: Step S1: The base station performs handover prediction based on the location information initially reported by the terminal, in order to predict all beams that theoretically cover the terminal and the target beam for handover. Step S2: When the distance between the current location and the location previously reported to the base station exceeds the distance threshold due to the terminal's own movement, proceed to step S5; otherwise, proceed to step S3. Step S3: When the terminal approaches the edge of the target beam, the base station sends a measurement control message based on the handover prediction result in step S1. The terminal performs routine measurements based on the measurement control message and periodically reports the measurement report to the base station. Step S4: The base station analyzes all beams that actually cover the terminal based on the measurement report in step S3, and verifies the coverage of the prediction results obtained in step S1. If the verification is successful, proceed to step S7; otherwise, proceed to step S5. Step S5: The terminal re-reports its location information to the base station. The base station then performs a handover prediction based on the location information to predict all beams that theoretically cover the terminal. Step S6: After a set time since the location information was re-reported, the terminal performs a burst measurement and uploads the measurement report to the base station; Step S7: The base station determines the handover decision based on the latest handover prediction results and the latest measurement report from the terminal, and performs coverage verification. If the verification passes, the handover decision is executed; otherwise, proceed to step S5. The coverage verification involves comparing whether all beams that theoretically cover the terminal are consistent with all beams that actually cover the terminal. If they are consistent, the verification passes; otherwise, the verification fails.

2. The measurement and control method for satellite networks according to claim 1, characterized in that: In step S6, the set time is the minimum measurement cycle that the satellite network can accept.

3. The measurement and control method for satellite networks according to claim 1, characterized in that: The measurement report includes the beam reference signal received power.

4. A measurement and control method for satellite networks according to claim 1, 2, or 3, characterized in that: In step S1, the handover prediction specifically involves the base station performing orbit prediction based on ephemeris to analyze the satellite's trajectory over a period of time, and predicting, based on the trajectory, the location of the base station, and the location of the terminal, all beams that theoretically cover the terminal and the target beam for handover.

5. A measurement and control method for satellite networks according to claim 1, 2, or 3, characterized in that: In step S3, the measurement control message includes three parts: measurement switch, measurement configuration, and measurement reporting. The measurement switch indicates when the terminal starts neighbor cell measurement, the measurement configuration indicates the measurement object and measurement period of the terminal, and the measurement reporting indicates when the terminal reports the measurement report. The neighbor cell refers to the adjacent beam of the target beam, which is determined by the base station. The measurement period setting requires that the terminal perform at least two neighbor cell measurements during the period from approaching the target beam to starting the handover, so as to achieve the purpose of assisting the handover.

6. A measurement and control method for satellite networks according to claim 1, 2, or 3, characterized in that: Both the conventional and burst measurements are at the same frequency or different frequency beam level.

7. The measurement and control method for satellite networks according to claim 4, characterized in that: When the received power of the beam reference signal in the measurement report is greater than the set power threshold, it is considered that the beam actually covers the terminal.

8. A measurement and control method for satellite networks according to claim 1, 2, or 3, characterized in that: The distance threshold is related to the beam radius of the current serving terminal.

9. A measurement and control method for satellite networks according to claim 1, 2, or 3, characterized in that: In step S6, after the set time, if the base station shuts down the transmission of measurement control messages, the terminal performs burst measurement according to the measurement control message previously sent by the base station; otherwise, the terminal performs burst measurement according to the current measurement control message.

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