A method for intelligent beam switching

Abstract

The application relates to the technical field of satellite communication, and discloses a beam intelligent switching method, which is applied to service connection switching between satellite mobile beams of a terminal and comprises the following steps: acquiring information about time changes of the terminal, a current service beam and candidate beams, and associating the information according to a unified time reference to form future service adaptation states of the beams relative to the terminal; determining a switching time as a switching opportunity according to the states, wherein the switching time is a time at which the current service beam cannot maintain the service connection; determining a target beam from the candidate beams, wherein the target beam supports service connection establishment or maintenance at the switching time; switching the service connection of the terminal to the target beam according to the switching time and the target beam; and forming a beam switching result containing the target beam identifier and a switching completion state. The application is used for improving the time matching and target selection rationality of connection switching in a satellite mobile beam scenario.

Description

Technical Field

[0001] This invention relates to the field of satellite communication technology, and more specifically, to a method for intelligent beam switching. Background Technology

[0002] In satellite mobile communication systems, low-Earth orbit (LEO) satellites move at high speeds relative to the ground, and the coverage area formed by the satellite beams on the ground shifts over time. Terminals may also be in vehicles, ships, aircraft, or handheld mobile scenarios. When a terminal moves from the service area of ​​one mobile beam to the service area of ​​another, the network needs to complete a service connection handover, including candidate beam measurement, handover determination, connection migration, and status confirmation. Existing mobile communication systems often use current link quality, reference signal strength, or fixed thresholds as the primary triggering criteria, suitable for terrestrial cellular scenarios where base station locations are relatively fixed and coverage boundaries change slowly. For LEO satellite mobile beams, the ground coverage of the current serving beam, the availability time of candidate beams, the terminal's direction of movement, and link quality all change simultaneously within a short period. Relying solely on current measurements for determination can easily lead to problems such as late handover triggering, insufficient target beam dwell time, and excessive resource consumption for cross-satellite or cross-frequency connection migration. Premature handover to avoid dropped connections may increase repeated handovers and signaling overhead. These issues affect the maintenance of terminal service connections and the scheduling of satellite network beam resources. Summary of the Invention

[0003] This invention provides a method for intelligent beam switching, which solves the technical problems mentioned in the background art.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution.

[0005] A method for intelligent beam switching, applied to the switching of service connections between satellite mobile beams by a terminal, includes:

[0006] Based on the information about the terminal, the current service beam, and the candidate beam changing over time, a future service adaptation state of the current service beam and the candidate beam relative to the terminal is formed. The future service adaptation state characterizes the service capability of the current service beam or the candidate beam relative to the terminal in a future time period.

[0007] Based on the future service adaptation status, the future moment when the service capability of the current service beam cannot maintain the service connection is determined as the switching opportunity;

[0008] From the candidate beams, determine the target beam that supports service connection establishment or service connection maintenance at the handover time.

[0009] Based on the switching timing and the target beam, the service connection of the terminal is switched from the current service beam to the target beam, and a beam switching result is formed, which includes the target beam identifier and the switching completion status.

[0010] Compared with the prior art, the present invention has the following substantial features and significant progress:

[0011] This invention takes time-varying information of the terminal, the current serving beam, and candidate beams as input, and correlates coverage relationships, relative motion relationships, and link quality relationships under a unified time reference to obtain the service adaptation status for future time periods. Based on this, it determines the handover timing and target beam, and then completes the service connection migration. Compared to methods that trigger handover solely based on current signal strength or a fixed threshold, this method can ensure that the handover determination corresponds to the coverage migration of the satellite moving beam, changes in terminal motion, and changes in link quality before the service capability of the current serving beam deteriorates to the point where the connection cannot be maintained. Simultaneously, the target beam must support the establishment or maintenance of a service connection at the handover timing, which helps reduce the mismatch between target selection and actual serviceable time, reduces unnecessary cross-satellite and cross-frequency connection migration resource consumption, and ensures that the beam handover result explicitly includes the target beam identifier and handover completion status, facilitating network-side connection management and terminal service maintenance. Attached Figure Description

[0012] Figure 1 This is a diagram illustrating the mechanism of cooperation between the demonstration terminal, the satellite mobile beam, and the network-side processing link of the present invention.

[0013] Figure 2 This is a flowchart illustrating the execution sequence from information acquisition to the formation of beam switching results according to the present invention. Detailed Implementation

[0014] The following description is provided in conjunction with the accompanying drawings. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the invention; those skilled in the art can make equivalent substitutions or combinations for the specific implementations.

[0015] This embodiment relates to a method for intelligent beam switching, applied to the switching of service connections between satellite mobile beams by a terminal. A satellite platform 112 forms a current service beam 113 and a candidate beam 114 on the ground, and the terminal 111 maintains a service connection through the current service beam 113. As the satellite platform 112 moves along its orbit, the coverage area of ​​the current service beam 113 and the candidate beam 114 on the ground shifts over time; when the terminal 111 is in a vehicle, ship, aircraft, or handheld usage scenario, the terminal 111's position, ground speed, and direction angle of motion also change over time. When service connection switching is triggered solely based on current link quality information, the network side relies on the link state at the time of switching triggering. There is a time difference between the switching timing and target beam selection and the actual service connection establishment time; therefore, this embodiment forms the future service adaptation state of the current service beam 113 and candidate beam 114 relative to the terminal 111 before switching triggering.

[0016] See Figure 1 This embodiment includes a time-varying information acquisition unit 115, a unified time reference unit 116, a future service adaptation state formation unit 117, a handover timing determination unit 118, a target beam determination unit 119, and a service connection handover execution and result output unit 120. The time-varying information acquisition unit 115 acquires information about the terminal 111, the current service beam 113, and the candidate beam 114 as they change over time. The unified time reference unit 116 associates this information with the same set of predicted times. The future service adaptation state formation unit 117 forms the future service adaptation states of the current service beam 113 and the candidate beam 114 relative to the terminal 111. The handover timing determination unit 118 determines the handover timing based on the future service adaptation states. The target beam determination unit 119 determines the target beam from the candidate beams 114. The service connection handover execution and result output unit 120 completes the service connection handover based on the handover timing and the target beam, and forms a beam handover result including the target beam identifier and the handover completion status.

[0017] See Figure 2This implementation follows steps S211 to S218. S211: Obtain information on the changes of terminal 111, current serving beam 113, and candidate beam 114 over time. S212: Associate the information using a unified time base. S213: Form the future service adaptation states of the current serving beam 113 and candidate beam 114 relative to terminal 111. S214: Determine whether the current serving beam 113 cannot maintain service connectivity in the future. If the determination is yes, S215: Determine the future time when the service capability of the current serving beam 113 cannot maintain service connectivity as the handover opportunity. S216: Filter candidate beams 114 that meet preset service availability conditions at the handover opportunity. S217: Determine the target beam. S218: Perform service connectivity handover based on the handover opportunity and the target beam, and form a beam handover result. If the determination is no, return to S211 to enter the next prediction update cycle.

[0018] The future service adaptation state characterizes the service capability of the current service beam 113 or candidate beam 114 relative to terminal 111 in a future time period. In this implementation, discrete states are formed on a predictive time basis, and the set of future relationships participating in the determination is determined by the service connection management configuration. The set of future relationships consists of one or more of future coverage relationships, future relative motion relationships, and future link quality relationships. When the set of future relationships contains only one type of future relationship, the future service adaptation state is formed based on that one type of future relationship; when the set of future relationships contains two types of future relationships, the future service adaptation state is formed based on those two types of future relationships; when the set of future relationships contains three types of future relationships, the future service adaptation state is formed based on a combination of future coverage relationships, future relative motion relationships, and future link quality relationships. Preset service availability conditions correspond to the set of future relationships. When all future relationships participating in the determination meet the corresponding conditions, the future service adaptation state is recorded as meeting the preset service availability conditions.

[0019] The service connection management configuration also specifies service hold-up time requirements, service connection handover preparation time, and service connection hold-up link quality requirements. The service hold-up time requirement determines the length of time the current service beam 113 or candidate beam 114 will maintain a service connection after the predicted time. The service connection handover preparation time determines whether the remaining service time of the current service beam 113 is sufficient to complete the target beam access. The service connection hold-up link quality requirements determine whether the future link quality status meets the link quality level required for service connection establishment or service connection hold. All of the above configuration items are associated with a unified time base and participate in the future service adaptation status determination within the same prediction update cycle.

[0020] In S211, the time-varying information acquisition unit 115 acquires terminal motion state information, current serving beam motion coverage information, candidate beam motion coverage information, and current link quality information. The terminal motion state information is formed from the terminal's historical trajectory information, which includes the terminal 111's position data at multiple acquisition times, as well as the terminal's motion speed change status and motion direction change status obtained from the position data at adjacent acquisition times. The current serving beam motion coverage information indicates the coverage area location, coverage range, and migration trend of the current serving beam 113 in the future time period. The candidate beam motion coverage information indicates the coverage area location, coverage range, and migration trend of the candidate beam 114 in the future time period. The current link quality information includes the current signal-to-interference-plus-noise ratio (SIR), current bit error rate (BER), reference signal received power, and measurements used by the satellite mobile communication system to determine the service connection maintenance status.

[0021] The current service beam motion coverage information and candidate beam motion coverage information are formed based on satellite trajectory information and beam pointing information. Satellite trajectory information is formed from at least one of ephemeris data, ground telemetry and control data, and inter-satellite link data. Ephemeris data includes semi-major axis, eccentricity, orbital inclination, right ascension of the ascending node, argument of perigee, and mean perigee. Ground telemetry and control data includes satellite longitude, latitude, orbital altitude, velocity, and attitude data measured by ground stations. Inter-satellite link data includes trajectory data transmitted between adjacent satellites. Beam pointing information includes the beam azimuth offset, beam elevation offset, and control adjustment status of the current service beam 113 and candidate beam 114 relative to the satellite platform 112.

[0022] In S212, the unified time reference unit 116 uses the system time maintained internally by the satellite mobile communication system as the unified time reference, and associates terminal motion status information, current serving beam motion coverage information, candidate beam motion coverage information, and current link quality information with the same set of predicted times. The system records various data using timestamps corrected by the time synchronization module, precise time protocol, or hardware timestamp. The terminal's historical trajectory information is sorted according to the acquisition time, and the predicted times falling between two adjacent acquisition times are used to form the corresponding position and terminal ground velocity using linear interpolation; the satellite trajectory information is time-aligned according to the ephemeris extrapolation result and the ground telemetry and control data of the previous cycle; the current link quality information is based on the most recent measurement value and is updated according to the satellite-ground geometry at the predicted time for input of future link quality status.

[0023] The unified time reference unit 116 outputs the terminal prediction input, the current serving beam prediction input, the candidate beam prediction input, and the link quality input at the same prediction time. The future service adaptation state formation unit 117 compares the location, beam coverage status, and link quality status of the terminal 111 at the same prediction time, so that subsequent judgments are based on the state data under the same time reference.

[0024] In S213, the future service adaptation state formation unit 117 forms a terminal prediction trajectory based on the terminal motion state information. The terminal prediction trajectory is a predicted position sequence of the terminal 111 relative to ground coordinates or system coordinates within a future time period. In this embodiment, a terminal trajectory prediction model is selected based on the terminal motion speed change state and terminal motion direction change state in the terminal's historical trajectory information, and then the terminal prediction trajectory is formed through the terminal trajectory prediction model.

[0025] The terminal trajectory prediction models include a static model, a uniform linear model, a uniform acceleration model, and a turning correction model. The future service adaptation state formation unit 117 selects the terminal trajectory prediction model in the following order: priority is given to changes in the terminal's motion direction, followed by changes in the terminal's motion speed, and then the terminal's ground speed. The change in the terminal's motion direction... Not less than And terminal ground speed Not less than At that time, the future service adaptation state formation unit 117 selects the turning correction model. The change in the terminal's motion direction. Less than And terminal acceleration The absolute value is located at to During this period, the future service adaptation state formation unit 117 selects a uniform acceleration model. The change in the terminal's motion direction... Less than And terminal acceleration The absolute value is less than At that time, the future service adaptation state formation unit 117 selects a uniform linear model. The terminal ground speed is less than And the change in the direction of terminal motion Less than At that time, the future service adaptation state formation unit 117 selects a static model. The above-mentioned judgment value is used for model selection; when entering coordinate calculation, the terminal ground velocity... Unified conversion to ,time Use seconds; use radians for angles in trigonometric functions.

[0026] When using the uniform linear model, the future service adaptation state forming unit 117 forms the terminal prediction trajectory based on the terminal's initial latitude, initial longitude, ground velocity, and direction angle. The terminal latitude is determined by the following formula:

[0027]

[0028] In the formula, For a moment The corresponding terminal latitude, To predict the terminal latitude at the start time, To complete the unit conversion of the terminal ground speed, The time is calculated from the start of the prediction. The terminal motion direction angle, numerical value This represents the approximate number of meters per degree in the latitudinal direction.

[0029] The terminal longitude is determined by the following formula:

[0030]

[0031] In the formula, For a moment The corresponding terminal longitude, To predict the terminal longitude at the starting time. Substitute the angle value .

[0032] When using the uniform acceleration model, the future service adaptation state forming unit 117 uses the terminal ground velocity at the prediction start time as the initial velocity, and at each prediction time, it adjusts the velocity according to the terminal acceleration. The terminal ground speed is corrected, and the corrected terminal ground speed is used to form the terminal prediction trajectory at that prediction moment. When using the turning correction model, the future service adaptation state formation unit 117 determines the terminal prediction trajectory based on the terminal ground speed. and the change in the direction of terminal motion Determine the terminal turning radius :

[0033]

[0034] In the formula, The turning radius at the terminal. To complete the unit conversion of the terminal ground speed, This represents the change in the direction of terminal motion calculated in radians. The time interval for collecting data on the change in the direction of terminal motion is determined. The turning radius of the terminal is then obtained. Subsequently, the future service adaptation state formation unit 117 predicts the terminal motion direction angle at the start time. Using the initial direction, at each predicted time point, the turning radius of the terminal is used as the reference. and terminal ground speed Update terminal motion direction angle and with the updated terminal motion direction angle The terminal prediction trajectory is formed on the turning path.

[0035] The future service adaptation state formation unit 117 also forms a prediction confidence ellipse based on the location covariance in the terminal's historical trajectory information. The prediction confidence ellipse is used to express the spatial uncertainty of the terminal's predicted trajectory and serves as an auxiliary basis for judging the future coverage adaptation state. The horizontal projection matrix of the location covariance matrix... Decompose according to the following formula:

[0036]

[0037] In the formula, The horizontal projection matrix of the position covariance matrix. The eigenvector matrix, and The eigenvalues ​​are used as the predictive confidence ellipse. The predictive confidence ellipse is expressed as follows:

[0038]

[0039] In the formula, and For the coordinate components of the predicted location along the principal axis of the prediction confidence ellipse, numerical values ​​are used. This corresponds to the elliptical boundary of the two-dimensional position error at a certain confidence level. Predict the semi-major axis of the confidence ellipse. and the predicted confidence ellipse minor semi-axis Determine them respectively using the following formulas:

[0040]

[0041]

[0042] The future service adaptation state formation unit 117 forms the current service beam predicted coverage state based on the current service beam motion coverage information, and forms the candidate beam predicted coverage state based on the candidate beam motion coverage information. The current service beam predicted coverage state indicates the location, range, and change trend of the coverage area of ​​the current service beam 113 in the future time period. The candidate beam predicted coverage state indicates the location, range, and change trend of the coverage area of ​​the candidate beam 114 in the future time period.

[0043] The current service beam motion coverage information and candidate beam motion coverage information are formed based on satellite trajectory information and beam pointing information. A passive beam drift state is formed based on the satellite trajectory information, and an active beam adjustment state is formed based on the beam pointing information. The current service beam motion coverage information and candidate beam motion coverage information are then formed based on both the passive beam drift state and the active beam adjustment state. The passive beam drift state indicates that the beam coverage area migrates as the satellite platform 112 moves. The active beam adjustment state indicates the state formed after the satellite platform 112 controls and adjusts the beam pointing according to service connection management needs.

[0044] The predicted satellite position is iteratively corrected using the theoretical predicted position and the error between the predicted satellite position and the previous cycle.

[0045]

[0046]

[0047] In the formula, The predicted satellite position for the next prediction time. The theoretically predicted position obtained from the orbital dynamics model. To correct the attenuation coefficient for satellite position prediction errors, This is the satellite position prediction error from the previous cycle. The satellite position measured in the previous cycle. These are the predicted satellite positions obtained from the previous period. All the above position vectors are in the same coordinate system. It is a dimensionless coefficient.

[0048] Based on the satellite's predicted position and beam pointing information, the future service adaptation state forming unit 117 determines the beam coverage center point and beam coverage radius. This implementation uses both the WGS84 coordinate system and local plane coordinates to describe the beam coverage state. The local plane coordinates take the location of terminal 111 at the predicted start time or the reference sub-satellite point configured on the network side as the origin, and the due east direction as the reference point. The positive axis, with true north as the reference direction. The positive axis; within the same prediction period, the terminal prediction trajectory, the current serving beam prediction coverage status, and the candidate beam prediction coverage status are all projected onto this local plane coordinate system for distance and coverage determination. In the local plane approximation for short prediction periods, the latitude of the beam coverage center point is... Determine by the following formula:

[0049]

[0050] In the formula, To ensure beam coverage of the center point latitude, The latitude of the satellite's nadir point at the same prediction time. This is the beam latitude pointing offset. This is the satellite orbit latitude offset correction amount. The latitude change of the satellite's nadir point at the same prediction time relative to the satellite's nadir point at the prediction start time is obtained. Longitude of the beam coverage center point. Determine by the following formula:

[0051]

[0052] In the formula, To determine the longitude of the center point of the beam coverage, The longitude of the satellite's nadir point at the same prediction time. This is the beam longitude pointing offset. This is the correction amount for the longitude offset of the satellite orbit. It is obtained from the change in longitude of the satellite's nadir point at the same prediction time relative to the satellite's nadir point at the prediction start time. , Both the offset and the value are expressed in degrees.

[0053] Beam coverage radius Determine by the following formula:

[0054]

[0055] In the formula, The beam coverage radius, The satellite's orbital altitude, The beam half-power angle, This is the beam coverage attenuation correction factor. Substituting it into the trigonometric function, the beam half-power angle... Convert to radians It is a dimensionless coefficient.

[0056] Beam pointing information includes beam azimuth offset. Beam pitch offset and the satellite's current attitude angle The beam latitude pointing offset and beam longitude pointing offset are determined by the following formulas:

[0057]

[0058]

[0059] In the formula, , and All beams use the same angular aperture; all are converted to radians before being substituted into trigonometric functions. Beam azimuth offset. Using the azimuth reference axis in the system of satellite platform 112 as the starting axis, the positive direction is defined according to the attitude data of satellite platform 112; beam elevation angle offset Using the pitch reference axis in the satellite platform 112 system as the starting axis, the positive direction is defined according to the attitude data of the satellite platform 112; the current attitude angle of the satellite. This is used to project the beam pointing component of the satellite platform 112 system onto local plane coordinates on the ground. When processing using local plane coordinates, the future service adaptation state forming unit 117 first obtains the beam coverage center point in local plane coordinates based on the beam pointing projection, and then obtains the latitude of the beam coverage center point according to the latitude-longitude conversion relationship of the WGS84 coordinate system. Longitude of the beam coverage center point .

[0060] When processing using the satellite platform 112 system, the future service adaptation state formation unit 117 first determines the satellite's current attitude angle. azimuth offset of the beam and beam pitch offset The beam direction is converted to Earth-fixed coordinates, and then the intersection of this beam direction with the Earth ellipsoid or a locally approximate surface is taken as the beam coverage center point. When processing using a local plane approximation, the future service adaptation state forming unit 117 converts the eastward and northward displacements of this intersection point in the local plane coordinates into longitude and latitude increments, and forms the latitude of the beam coverage center point. Longitude of the beam coverage center point .

[0061] The future service adaptation state formation unit 117 determines the set of future relationships to be determined based on the service connection management configuration. When the set of future relationships includes future coverage relationships, the future service adaptation state formation unit 117 forms a future coverage adaptation state based on the terminal predicted trajectory, the current service beam predicted coverage state, and the candidate beam predicted coverage state. When the set of future relationships includes future relative motion relationships, the future service adaptation state formation unit 117 forms a future relative motion adaptation state based on the terminal predicted trajectory, the current service beam motion coverage information, and the candidate beam motion coverage information. When the set of future relationships includes future link quality relationships, the future service adaptation state formation unit 117 forms a future link quality state based on the terminal predicted trajectory, the current service beam predicted coverage state, the candidate beam predicted coverage state, and the current link quality information. In the complete implementation of this embodiment, the set of future relationships includes future coverage relationships, future relative motion relationships, and future link quality relationships, and the future service adaptation state is formed based on the future coverage adaptation state, the future relative motion adaptation state, and the future link quality state.

[0062] The future coverage relationship indicates whether terminal 111 will be within the coverage area corresponding to the current serving beam's predicted coverage state or the candidate beam's predicted coverage state in the future time period. The future coverage adaptation state is formed based on the overlap between the terminal's predicted trajectory and the beam's coverage area. For the current serving beam 113, the future coverage adaptation state indicates the degree to which the current serving beam 113 maintains coverage for terminal 111 in the future time period. For the candidate beam 114, the future coverage adaptation state indicates whether the candidate beam 114 can cover terminal 111 near the handover time.

[0063] When the beam coverage area is elliptical, the center of the beam coverage area is The major semi-axis is The minor semi-axis is The terminal trajectory is and Combining the terminal trajectory with the beam coverage area, we obtain:

[0064]

[0065] The coefficients of the quadratic equation are determined by the following formula:

[0066]

[0067]

[0068]

[0069] In the formula, and To predict the terminal plane coordinates at the start time, and The components of the terminal ground velocity in the plane coordinate system. and The coordinates of the center of the beam coverage area and Let these be the major and minor semi-axis of the beam coverage area. The coordinates, velocity, and semi-axis use the same unit of length. The positive root of the distance from within the coverage area to outside the coverage area, obtained from this quadratic equation, is taken as the time it takes for terminal 111 to leave the beam coverage area, and the remaining communication time is calculated accordingly. .

[0070] The future relative motion relationship represents the relative motion trend between terminal 111 and the current serving beam 113 or candidate beam 114. The future relative motion adaptation state is formed based on the satellite-end relative velocity, approach velocity, terminal motion direction change, and beam coverage area migration direction. The service hold-up time requirement is given by the service connection management configuration of the satellite mobile communication system, in seconds, and represents the shortest time required for the beam to maintain a service connection after the corresponding predicted time. The distance from the terminal corresponding to the current serving beam 113 to the beam coverage center point continues to increase, and the remaining communication time... When the service hold-up time requirement is lowered, the future relative motion adaptation state of the current serving beam 113 is recorded as not meeting the preset service availability conditions at the corresponding prediction time. The distance from the terminal corresponding to the candidate beam 114 to the beam coverage center point is maintained within the beam coverage radius. Within, and the remaining communication time When the service hold-up time requirement is met, the future relative motion adaptation state of candidate beam 114 is recorded as meeting the preset service availability conditions.

[0071] The future link quality relationship indicates the change in link quality between terminal 111 and the current serving beam 113 or candidate beam 114 over a future period. The future link quality status is based on the current link quality information, combined with the future satellite-to-ground geometry, beam coverage center point, and beam coverage radius. Interference power from adjacent beams on the same frequency. Received carrier power. The power is generated from the reference signal received power in the current link quality information; for the current serving beam 113, the future service adaptation state forming unit 117 uses the most recent reference signal received power as a reference, and obtains the received carrier power at each prediction time according to the future propagation distance change, beam off-axis gain change and terminal receiving antenna gain configuration. For candidate beam 114, the future service adaptation state forming unit 117 reads the reference signal received power measurement value of candidate beam 114 or the candidate beam reference signal power configuration sent by the network side, and obtains the received carrier power according to the same link budget caliber. The link budget is obtained first. The received carrier power is represented and noise power Interference power with adjacent beams on the same frequency Unified as Aperture. Future signal-to-interference-to-noise ratio Determine by the following formula:

[0072]

[0073] In the formula, For a moment The future signal-to-interference-plus-noise ratio, For a moment The received carrier power, For noise power, For a moment The co-channel adjacent beam interference power. This formula first converts the received carrier power, noise power, and co-channel adjacent beam interference power to the linear power domain, calculates their ratios, and then outputs the power as... The future signal-to-interference-plus-noise ratio is represented.

[0074] Free space path loss Determine by the following formula:

[0075]

[0076] In the formula, For free space path loss, For The carrier frequency is represented. For The propagation distance is indicated. When other carrier frequency units or distance units are used, the satellite mobile communication system uses the path loss constant corresponding to the combination of those units.

[0077] When adjacent beams of the same frequency exist, the interference power of adjacent beams of the same frequency Determine by the following formula:

[0078]

[0079] In the formula, For the first Adjacent co-frequency beams at time Interference power reaching terminal 111 by Adjacent co-frequency beams are determined according to the beams that use the same frequency as the currently serving beam 113 or candidate beam 114 and are registered in the co-frequency neighbor cell configuration on the network side; Interference power of adjacent co-frequency beams The off-axis antenna gain is determined by the satellite transmit power of the adjacent co-frequency beams, the off-axis antenna gain at the same prediction time, the free-space path loss, and the terminal receiving antenna gain configuration. The off-axis angle between the coverage center point, the predicted terminal location, and the pointing direction of each adjacent co-frequency beam is determined. Both adopt the same power as the received carrier. The same Budget scope.

[0080] This implementation uses discrete states to form the future service adaptation state. For each prediction time, the future service adaptation state forming unit 117 first reads the future relationship set in the service connection management configuration, and then determines the future relationships contained in the future relationship set. When the future relationship set only contains future coverage relationships, the future service adaptation state is determined by whether the future coverage adaptation state meets the preset service availability conditions. When the future relationship set only contains future relative motion relationships, the future service adaptation state is determined by whether the future relative motion adaptation state meets the preset service availability conditions. When the future relationship set only contains future link quality relationships, the future service adaptation state is determined by whether the future link quality state meets the link quality requirements required for service connection establishment or service connection maintenance. When the future relationship set contains two or three future relationships, if all the states involved in the determination are satisfied, the future service adaptation state of the corresponding beam at that prediction time is recorded as meeting the preset service availability conditions; if any of the states involved in the determination are not satisfied, the future service adaptation state of the corresponding beam at that prediction time is recorded as not meeting the preset service availability conditions.

[0081] In S214, the handover timing determination unit 118 determines whether the current service beam 113 cannot maintain service connectivity in the future time period based on the future service adaptation status. In S215, the handover timing determination unit 118 reads the future service adaptation status of the current service beam 113 in the order of the predicted times; if at least one of the future coverage adaptation status, future relative motion adaptation status, and future link quality status of the current service beam 113 does not meet the preset service availability conditions, the corresponding future time is determined as the handover timing.

[0082] The future coverage adaptation status of the current service beam 113 does not meet the preset service availability conditions. This is manifested in the terminal's predicted trajectory exceeding the coverage area corresponding to the current service beam's predicted coverage status at the corresponding prediction time, or the remaining communication time... This is less than the service connection handover preparation time. The service connection handover preparation time is provided by the service connection management configuration and is in seconds. It covers the time required for the service connection handover command to be issued, the target beam resource configuration to take effect, and the service connection to be established. The future relative motion adaptation state of the current service beam 113 does not meet the preset service availability conditions, which is manifested as the continuous separation between the coverage area of ​​terminal 111 and the current service beam 113, resulting in the remaining communication time of the current service beam 113 after the corresponding future moment. The service hold-up time requirement is lower than required. The future link quality status of the current serving beam 113 does not meet the preset service availability conditions, which is manifested in the future signal-to-interference-plus-noise ratio (SIR), bit error rate (BER), or reference signal received power failing to meet the service connection hold-up link quality requirements. The service connection hold-up link quality requirements are determined by the service type and network-side link hold-up configuration. In the numerical embodiment, the future quality failure SIR threshold is used as the judgment value.

[0083] After the handover timing determination unit 118 outputs the handover timing, the target beam determination unit 119 determines the target beam only from the candidate beams 114 corresponding to that handover timing. When the current serving beam 113 meets the preset service availability conditions throughout the entire prediction period, the handover timing determination unit 118 does not output a new handover timing, and the system enters the next prediction update cycle and reacquires information that changes over time.

[0084] In S216, the target beam determination unit 119 selects candidate beams 114 from the candidate beams 114 that meet preset service availability conditions at the handover time. During the selection process, the target beam determination unit 119 reads the future coverage adaptation status, future relative motion adaptation status, and future link quality status of the candidate beam 114 at the handover time. If the candidate beam 114 covers the terminal 111 at the handover time, the relative motion trend supports service connection maintenance, and the future link quality status meets the service connection establishment or service connection maintenance requirements, then the candidate beam 114 is retained as a comparable candidate beam 114.

[0085] In S217, the target beam determination unit 119 compares the future coverage adaptation status, future relative motion adaptation status, future link quality status, and candidate beam handover cost status of the selected candidate beams 114 according to a preset priority relationship. Priority is given to candidates with higher coverage retention in the future coverage adaptation status, specifically the duration of coverage of the candidate beam 114 over the terminal's predicted trajectory after the handover. Priority is given to candidates with lower relative motion separation trends in the future relative motion adaptation status, specifically the trend of distance change between the terminal 111 and the coverage center point of the candidate beam 114, and the remaining communication time. Prioritize candidates with higher future link quality retention rates, specifically comparing the future signal-to-interference-plus-noise ratio (SNR) margin relative to the service connection retention link quality requirements. Prioritize candidates with lower connection migration resource consumption corresponding to their candidate beam switching cost status, specifically comparing the network-side processing resources required for inter-beam resource configuration, cross-satellite resource coordination, frequency switching configuration, service connection context migration, and service connection switching command issuance.

[0086] The candidate beam switching cost status represents the status of the connection migration resources required to change the service connection of terminal 111 from the current service beam 113 to the corresponding candidate beam 114. The candidate beam switching cost status does not replace the preset service availability conditions; if candidate beam 114 does not meet the preset service availability conditions, it will not be included in the candidate beam switching cost status comparison. If multiple candidate beams 114 cannot be distinguished after comparison based on preset priority relationships, the target beam determination unit 119 determines the target beam according to the candidate beam sorting rules configured in the network. The candidate beam sorting rules configured in the network are preset by the satellite mobile communication system and specify the candidate beam identifier order, service priority order, or network-side resource status order in the service connection management configuration.

[0087] The target beam determination unit 119 determines the candidate beam 114 with the highest priority result as the target beam and outputs the target beam identifier to the service connection handover execution and result output unit 120. The target beam is the candidate beam 114 that supports service connection establishment or service connection maintenance at the handover time. Its determination result and the handover time together serve as the input for performing service connection handover in S218.

[0088] In S218, the service connection handover execution and result output unit 120 performs service connection handover according to the handover timing and target beam and generates a beam handover result. The object of the service connection handover is the service connection of terminal 111, and the direction of the service connection handover is from the current service beam 113 to the target beam. The target beam is used to determine the beam after the service connection handover, and the handover timing is used to determine the planned completion time and command issuance sequence of the service connection handover.

[0089] When performing a service connection handover, the service connection handover execution and result output unit 120 establishes a service connection between terminal 111 and the target beam under an overlapping service state where both the current service beam 113 and the target beam meet preset service availability conditions. After the service connection between terminal 111 and the target beam is established, the service connection between terminal 111 and the current service beam 113 is terminated. The overlapping service state occurs during the period when the current service beam 113 can still maintain a service connection and the target beam has already supported the establishment of a service connection; this period is located before or near a future time when the service capability of the current service beam 113 can no longer maintain a service connection.

[0090] The network side issues a service connection switching command to terminal 111. The service connection switching command includes the target beam identifier, switching timing, resource configuration required for target beam access, and service connection establishment parameters. The resource configuration required for target beam access includes the frequency identifier corresponding to the target beam, time-frequency resource location, random access preamble or pilot resources, uplink synchronization adjustment, and transmit power control parameters. The service connection establishment parameters include the service connection context identifier of terminal 111, target beam bearer configuration, confirmation message reception timing, and service connection establishment completion reporting method. According to the service connection switching command, terminal 111 uses the resource configuration required for target beam access to establish a service connection with the target beam within the command timing corresponding to the switching timing. After the service connection between terminal 111 and the target beam is established, the network side releases the service connection resources associated with terminal 111 in the current service beam 113.

[0091] The beam switching result includes a target beam identifier and a switching completion status. The target beam identifier is used to identify the target beam after the service connection switch; the switching completion status indicates that the service connection of terminal 111 has changed from the current service beam 113 to the target beam. The beam switching result is output to the network-side connection management unit, or reported by terminal 111 to the network-side connection management unit. The network-side connection management unit updates the input status of the beam to which terminal 111 belongs, connection migration resource usage, and subsequent predicted update cycles based on the beam switching result.

[0092] Before performing a service connection handover based on the handover timing and target beam, the service connection handover execution and result output unit 120 determines whether the handover anti-jitter conditions are met. The handover anti-jitter conditions include: during the continuous determination process before reaching the handover timing, the target beam meets the preset service availability conditions at the handover timing, and the current service beam 113 does not meet the preset service availability conditions at the handover timing; and the terminal 111 is not in a post-handover locked state. In this embodiment, the continuous determination process employs at least two consecutive prediction update cycles; the prediction update cycle is provided by the service connection management configuration. When the same state is obtained for the same handover timing in both consecutive prediction update cycles, the state in the handover anti-jitter conditions remains valid.

[0093] When the handover stabilization conditions are met, the network side issues a service connection handover command. After the service connection handover is completed, terminal 111 enters a post-handover lock state and maintains the service connection of the target beam until the post-handover lock state ends. In this embodiment, the post-handover lock state ends according to the post-handover lock duration configured by the network side. The post-handover lock duration can be... After the lockout ends following the switchover, the satellite mobile communication system continues to execute steps S211 through S218.

[0094] The data flow process of this embodiment is described below using a control cycle.

[0095] The satellite mobile communication system includes a satellite platform 112, which forms the current service beam 113 and candidate beams 114. The system maintains the current time using a unified time reference. and future prediction moments , and The prediction period is the future. The interval between adjacent prediction times is In this embodiment, the prediction update period is set to... That is, the system every Re-execute S211 to S218 and re-form the next group. , and Predicted time. Terminal 111 at Maintain service connectivity at all times through the current service beam 113.

[0096] At the start of this control cycle, S211 acquires information that changes over time. Terminal 111 in Initial latitude of the terminal at time for Initial longitude of the terminal for Terminal ground speed for Converted to Terminal motion direction angle for .forward The terminal's historical trajectory information displays the terminal's acceleration. The absolute value is less than Change in the direction of terminal motion Less than Therefore, S213 selects a uniform linear model to form the terminal predicted trajectory.

[0097] S212 associates terminal motion state information, current serving beam motion coverage information, candidate beam motion coverage information, and current link quality information with... , , and After substituting the terminal latitude calculation formula and the terminal longitude calculation formula, the future service adaptation state formation unit 117 obtains... The predicted position of time terminal 111 is , ,get The predicted position of time terminal 111 is , ,get The predicted position of time terminal 111 is , .by The position of terminal 111 is the origin of the local plane coordinate system. , and The plane coordinates are approximately as follows: , and .

[0098] Satellite orbital altitude within the same control cycle for Beam half-power angle for Beam coverage attenuation correction factor for The beam half-power angle Converting to radians and inputting into the beam coverage radius formula yields the beam coverage radius. Approximately The current service beam prediction coverage status is in , and The plane coordinates of the coverage center point are as follows: , and One of the candidate beams in candidate beam 114 is in and The plane coordinates of the coverage center point are as follows: and .

[0099] The future service adaptation state forming unit 117 forms the future coverage adaptation state of the current service beam 113 based on the terminal's predicted trajectory and the current service beam's predicted coverage state. The distance from the terminal 111 to the coverage center point of the current service beam 113 is within... , and Approximately , and .because and The distance is less than the beam coverage radius The current serving beam 113 is in and The future coverage adaptation status meets the preset service availability conditions; due to The distance is greater than the beam coverage radius The current serving beam 113 is in The future coverage adaptation status does not meet the preset service availability conditions. The distance from terminal 111 to the coverage center point of the candidate beam in candidate beam 114 is within and Approximately and All are smaller than the beam coverage radius. The candidate beam in The future coverage adaptation status meets the preset service availability conditions.

[0100] The future service adaptation state forming unit 117 forms the future relative motion adaptation state based on the distance change trend. The distance from the terminal corresponding to the current service beam 113 to the beam coverage center point is from... Increase to and in Beyond the beam coverage radius Therefore, the current serving beam 113 is in The future relative motion adaptation state does not meet the preset service availability conditions. The candidate beam in candidate beam 114... and All of them maintain a small distance from the terminal's predicted trajectory, and their relative motion trends support the maintenance of subsequent service connections. Therefore, this candidate beam is... The future relative motion adaptation state meets the preset service availability conditions.

[0101] The future service adaptation state formation unit 117 forms the future link quality state based on the current link quality information and the future satellite-to-ground geometric relationship. In this embodiment, the future quality failure signal-to-interference-plus-noise ratio threshold is... Received carrier power The co-frequency adjacent beam interference power is obtained by combining the received power of the reference signal with changes in future propagation distance and beam off-axis gain. The interference power of six adjacent co-frequency beams is in the same order. Budget definition established. Current service beam 113 is... Received carrier power at time for noise power for Co-frequency adjacent beam interference power for Substituting the values ​​into the future signal-to-interference-plus-noise ratio (SINNR) calculation formula, the future SINNR is approximately... The current serving beam 113 is in Received carrier power at time for noise power for Co-frequency adjacent beam interference power for The future signal-to-interference-plus-noise ratio is approximately The current serving beam 113 is in Received carrier power at time for noise power for Co-frequency adjacent beam interference power for The future signal-to-interference-plus-noise ratio is approximately Therefore, the current serving beam 113 is in The future link quality status does not meet the preset service availability conditions. This candidate beam in candidate beam 114... Received carrier power at time for noise power for Co-frequency adjacent beam interference power for The future signal-to-interference-plus-noise ratio is approximately The preset service availability conditions are met.

[0102] In S214 and S215, the switching timing determination unit 118 follows the instructions. , and The future service adaptation status of the current service beam 113 is read sequentially. The current service beam 113 is... and The future coverage adaptation status, future relative motion adaptation status, and future link quality status all meet the preset service availability conditions; the current service beam 113 is in The future coverage adaptation status and future link quality status both fail to meet the preset service availability conditions, and the future relative motion adaptation status also fails to meet the preset service availability conditions. The handover timing determination unit 118 will... The timing for the switchover has been determined.

[0103] In S216, the target beam determination unit 119 filters candidate beams 114 that meet preset service availability conditions at the handover timing. The candidate beam in candidate beam 114... Terminal 111 is covered, and its future relative motion adaptation status meets the preset service availability conditions, with a future signal-to-interference-plus-noise ratio of approximately [value missing]. Therefore, it was retained as a comparable candidate beam 114. Another candidate beam is... Although it meets the requirements for future link quality status, its coverage duration for the terminal's predicted trajectory after the handover is shorter than that of the candidate beam. The target beam determination unit 119 first compares the future coverage adaptation status according to the preset priority relationship, and determines the candidate beam with the higher coverage retention degree as the candidate beam 114 with the highest priority result, and determines it as the target beam.

[0104] Before S218, the service connection handover execution and result output unit 120 determines the handover anti-jitter conditions. Upon arrival... In the previous two consecutive prediction update cycles, the target beam was in The preset service availability conditions are met, and the current service beam 113 is in... If the preset service availability conditions are not met, and terminal 111 is not in a post-handover locked state, the handover anti-jitter condition is met. The network side issues a service connection handover command in an overlapping service state where both the current service beam 113 and the target beam meet the preset service availability conditions. The service connection handover command includes the target beam identifier, handover timing, frequency point identifier corresponding to the target beam, time-frequency resource location, random access preamble resource or pilot resource, uplink synchronization adjustment amount, transmit power control parameters, and service connection establishment completion reporting method.

[0105] Terminal 111 establishes a service connection with the target beam according to the service connection switching command. After the service connection between terminal 111 and the target beam is established, the network side disconnects the service connection between terminal 111 and the current service beam 113. The service connection switching execution and result output unit 120 generates a beam switching result. The target beam identifier in the beam switching result indicates the target beam after the service connection switch. The switching completion status indicates that the service connection of terminal 111 has changed from the current service beam 113 to the target beam. After the service connection switch is completed, terminal 111 enters a post-switching locked state and maintains the service connection of the target beam until the post-switching locked state ends.

[0106] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A method for intelligent beam switching, applied to the switching of service connections between satellite mobile beams by a terminal, characterized in that, include: Based on the information about the terminal, the current service beam, and the candidate beam changing over time, a future service adaptation state of the current service beam and the candidate beam relative to the terminal is formed. The future service adaptation state characterizes the service capability of the current service beam or the candidate beam relative to the terminal in a future time period. Based on the future service adaptation status, the future moment when the service capability of the current service beam cannot maintain the service connection is determined as the switching opportunity; From the candidate beams, determine the target beam that supports service connection establishment or service connection maintenance at the handover time. Based on the switching timing and the target beam, the service connection of the terminal is switched from the current service beam to the target beam, and a beam switching result is formed, which includes the target beam identifier and the switching completion status.

2. The method for intelligent beam switching according to claim 1, characterized in that, The information that changes over time includes terminal motion status information, current service beam motion coverage information, candidate beam motion coverage information, and current link quality information. The terminal motion status information, the current service beam motion coverage information, the candidate beam motion coverage information, and the current link quality information are associated according to a unified time reference. The future service adaptation state is formed based on at least one of the future coverage relationship, future relative motion relationship, and future link quality relationship between the terminal and the current service beam or the candidate beam. The preset service availability condition is the service availability condition determined based on at least one of the future coverage relationship, the future relative motion relationship, and the future link quality relationship.

3. The method for intelligent beam switching according to claim 2, characterized in that, The formation of the aforementioned future service adaptation state includes: A terminal predicted trajectory is formed based on the terminal motion state information; a current service beam predicted coverage state is formed based on the current service beam motion coverage information; a candidate beam predicted coverage state is formed based on the candidate beam motion coverage information; a future coverage adaptation state is formed based on the current service beam predicted coverage state and the candidate beam predicted coverage state; a future relative motion adaptation state is formed based on the terminal predicted trajectory, the current service beam motion coverage information, and the candidate beam motion coverage information; a future link quality state is formed based on the terminal predicted trajectory, the current service beam predicted coverage state, the candidate beam predicted coverage state, and the current link quality information; and a future service adaptation state is formed based on the future coverage adaptation state, the future relative motion adaptation state, and the future link quality state.

4. The method for intelligent beam switching according to claim 3, characterized in that, The terminal motion state information is formed from the terminal's historical trajectory information. A terminal trajectory prediction model is selected based on the terminal's motion speed change state and terminal motion direction change state in the terminal's historical trajectory information, and the terminal predicted trajectory is formed through the terminal trajectory prediction model.

5. The method for intelligent beam switching according to claim 3, characterized in that, The current service beam motion coverage information and the candidate beam motion coverage information are formed based on satellite trajectory information and beam pointing information. The satellite trajectory information is formed from at least one of ephemeris data, ground telemetry and control data, and inter-satellite link data. A passive beam drift state is formed based on the satellite trajectory information, an active beam adjustment state is formed based on the beam pointing information, and the current serving beam motion coverage information and the candidate beam motion coverage information are formed based on the passive beam drift state and the active beam adjustment state.

6. The method for intelligent beam switching according to claim 3, characterized in that, Determining the switching timing includes: When the future service adaptation state indicates that at least one of the future coverage adaptation state, future relative motion adaptation state, and future link quality state of the current service beam does not meet the preset service availability conditions, the future moment when the preset service availability conditions are not met is determined as the handover timing.

7. The method for intelligent beam switching according to claim 3, characterized in that, Determining the target beam includes: From the candidate beams, candidate beams that meet the preset service availability conditions at the handover time are selected. The future coverage adaptation status, future relative motion adaptation status, future link quality status, and candidate beam handover cost status of the selected candidate beams are compared in sequence according to the preset priority relationship. The candidate beam with the highest priority result is determined as the target beam. The preset priority relationships include those with higher coverage retention in future coverage adaptation states, those with lower relative motion separation trends in future relative motion adaptation states, those with higher link quality retention in future link quality states, and those with lower connection migration resource consumption corresponding to candidate beam switching cost states. When multiple candidate beams are obtained according to the preset priority relationship, the target beam is determined according to the candidate beam sorting rules configured in the network. The candidate beam switching cost status represents the status of the connection migration resources required to change the terminal's service connection from the current service beam to the corresponding candidate beam.

8. The method for intelligent beam switching according to claim 2, characterized in that, Switching the terminal's service connection from the current service beam to the target beam includes: In an overlapping service state where both the current serving beam and the target beam meet the preset service availability conditions, a service connection is established between the terminal and the target beam, and after the service connection between the terminal and the target beam is established, the service connection between the terminal and the current serving beam is terminated.

9. The method for intelligent beam switching according to claim 2, characterized in that, Based on the switching timing and before performing service connection switching on the target beam, determine whether the switching anti-shake conditions are met; The switching anti-shake conditions include: during the continuous determination process before the switching time is reached, the state in which the target beam meets the preset service availability condition at the switching time and the current service beam does not meet the preset service availability condition at the switching time remains established, and the terminal is not in a post-switching locked state. When the switching anti-shake conditions are met, a service connection switching command is issued. After the service connection switching is completed, the system enters the post-switching lock state and maintains the service connection of the target beam until the post-switching lock state ends.

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