Base station switching method and system based on track prediction

Abstract

The invention discloses a base station switching method and system based on track prediction, and the method comprises the steps: a currently connected ground base station sends an uplink message and a reference message to an airplane in real time, and other ground base stations send reference messages to the airplane in real time; the airplane establishes a ground base station list according to the received uplink message and reference signal sent by the ground base station; the airplane periodically analyzes the ground base station list, selects the ground base stations of which the signal quality is in a rising trend and is higher than a set threshold value as alternative stations, and establishes an alternative station list; the airplane sends a message to the ground base station management system and carries own identity information, a next waypoint and a preferred alternative station list; and the ground base station management system establishes an airplane list according to the received message sent by the airplane and executes switching of the ground base station. According to the invention, the problems of frequent switching, increased communication delay, even link interruption and the like caused by switching only according to the reference signal strength are solved.

Description

Technical Field

[0001] The present invention relates to the field of civil aviation mobile communications, and in particular to a base station switching method and system based on track prediction. Background Art

[0002] In a terrestrial mobile network, a terminal usually reselects a cell (base station) by measuring the cell reference signal strength during movement to complete handover between cells (base stations). The handover process is initiated by the terminal, and the cell (base station) does not participate in the decision-making process of the handover.

[0003] Compared with ground mobile communications, civil aircraft mobile communications have two characteristics: (1) the movement of civil aircraft is not random, but is based on a flight plan (track) agreed upon between the air and the ground; (2) civil aircraft move very fast and base station switching is frequent.

[0004] The line-of-sight communication methods currently used by civil aircraft include VDL link, LDACS link, ATG link and AeroMACS link. Among them, VDL link, LDACS link and ATG link are suitable for air-to-ground communication in the airway, involving base station switching scenarios during high-speed movement.

[0005] VDL links are divided into two modes: Mode A and Mode 2. According to the ARINC 618 specification, VDL Mode A uses the method of detecting the signal quality of the ground station (SQP) to decide whether to switch, but the ARINC 618 specification does not specify the principle based on which to select the next station. According to the ARINC 631 specification, VDL Mode 2 comprehensively considers factors such as SQP, maximum number of retransmissions (N2), maximum waiting time of the MAC layer after receiving the RTS word (TM2), and maximum idle activity time (TG2) to decide whether to switch, and switch to the station with the best current SQP.

[0006] The LADACS link and ATG link are built based on mature terrestrial mobile network technology (4G / 5G). They reselect cells (base stations) by measuring the strength of cell reference signals and complete switching between cells (base stations).

[0007] Therefore, the existing switching scheme only switches according to the reference signal strength, resulting in problems such as frequent switching (jitter), increased communication delay and even link interruption. Summary of the invention

[0008] The technical problem to be solved by the present invention is that the existing switching scheme in the field of civil aviation mobile communications only switches according to the reference signal strength, resulting in frequent switching (jittering), increased communication delay and even link interruption. The purpose of the present invention is to provide a base station switching method and system based on track prediction. The present invention is a base station switching between an aircraft and a ground base station based on track prediction, which improves the predictability of the base station switching scenario and the air-ground collaboration capability, so as to solve the problems of frequent switching (jittering), increased communication delay and even link interruption caused by switching only according to the reference signal strength.

[0009] The present invention is achieved through the following technical solutions:

[0010] In a first aspect, the present invention provides a base station switching method based on track prediction, which is suitable for base station switching between an aircraft and multiple ground base stations, where the ground base stations are networked in the same frequency or in different frequencies; the method comprises:

[0011] The ground base station currently establishing the connection sends uplink messages and reference messages to the aircraft in real time, and other ground base stations send reference messages to the aircraft in real time;

[0012] The aircraft establishes a list of ground base stations according to the uplink message and reference signal received from the ground base station; and updates the list of ground base stations each time an uplink message or reference signal is received from the ground base station;

[0013] The aircraft periodically analyzes the list of ground base stations, selects ground base stations whose signal quality is on an upward trend and is higher than a set threshold as candidate stations, and establishes a list of candidate stations;

[0014] The aircraft sends a message to the ground base station management system with its own identity information, next waypoint, and a list of preferred alternative stations;

[0015] The ground base station management system establishes an aircraft list based on the messages received from the aircraft and executes the switching of the ground base stations.

[0016] Furthermore, the ground base station that currently establishes a connection carries its own identity information and its own location information when sending an uplink message to the aircraft in real time.

[0017] Furthermore, when the ground base station that is currently establishing a connection sends a reference message to the aircraft in real time, it carries its own identity information, its own location information, neighboring station identity information, neighboring station location information and neighboring station frequency information.

[0018] Furthermore, the ground base station list includes ground base station identity information, ground base station location information, current signal quality, signal quality historical data, ground base station frequency information and neighboring station information, and the neighboring station information includes neighboring station identity information, neighboring station location information and neighboring station frequency information.

[0019] Furthermore, ground base stations whose signal quality is on an upward trend and is higher than a set threshold are selected as candidate stations, and a candidate station list is established, including:

[0020] Analyze historical signal quality data and select ground base stations whose signal quality is on an upward trend and above a set threshold as candidate stations;

[0021] The candidate stations are sorted based on the distance relative to the next waypoint to form a candidate station list; in the sorting process, those with shorter distances have higher priority.

[0022] Further, executing the handover of the ground base station includes:

[0023] When the aircraft detects that the signal quality of the ground base station currently connected is lower than the set threshold, the aircraft initiates a switching request to the ground base station system and selects the ground base station with the highest ranking from the candidate list as the ground base station to be switched to;

[0024] When the ground base station management system detects that the aircraft signal quality is lower than the set threshold, it selects a ground base station from the candidate station list sent by the aircraft in combination with the current network load and actively requests the aircraft to switch to the ground base station.

[0025] Furthermore, the aircraft list includes aircraft identity information, signal quality, next waypoint, currently connected ground base station and candidate station list.

[0026] Furthermore, when the ground base stations are networked in different frequencies, a ground base station list is established, including:

[0027] When the aircraft detects that the signal quality is lower than the set threshold, it starts to scan the frequency. The scanning frequency is the neighboring station frequency included in the reference signal of the ground base station.

[0028] After completing the frequency scan, the aircraft generates a list of ground stations.

[0029] Furthermore, when the ground base stations are networked in different frequencies, the switching of the ground base stations includes:

[0030] When the aircraft detects that the signal quality of the currently connected ground base station is lower than the set threshold, the aircraft will select the ground base station closest to the next waypoint from the ground base station list for switching, and the aircraft will reset the frequency of the ground base station;

[0031] When the ground base station management system detects that the aircraft signal quality is lower than the set threshold, the ground base station actively requests the aircraft to switch to the ground base station that is closest to the next waypoint and has unsaturated capacity.

[0032] In a second aspect, the present invention further provides a base station switching system based on track prediction, which is suitable for base station switching between an aircraft and multiple ground base stations, where the ground base stations are networked in the same frequency or in different frequencies; the system comprises:

[0033] The first message sending unit is used for the ground base station currently establishing a connection to send an uplink message and a reference message to the aircraft in real time, and other ground base stations to send a reference message to the aircraft in real time;

[0034] A base station list establishment and update unit, used for the aircraft to establish a ground base station list according to the uplink message and reference signal sent by the ground base station; and update the ground base station list each time an uplink message or reference signal sent by the ground base station is received;

[0035] An analysis and candidate station list establishment unit, used for the aircraft to periodically analyze the ground base station list, select ground base stations whose signal quality is on an upward trend and is higher than a set threshold as candidate stations, and establish a candidate station list;

[0036] The second message sending unit is used for the aircraft to send a message to the ground base station management system and carry its own identity information, the next waypoint, and a preferred alternative station list;

[0037] The base station switching unit is used for the ground base station management system to establish an aircraft list according to the received messages sent by the aircraft and execute the switching of the ground base station.

[0038] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0039] 1. The present invention provides a base station switching method and system based on track prediction. The present invention is a base station switching between an aircraft and a ground base station based on track prediction, which improves the predictability of base station switching scenarios and air-ground collaboration capabilities to solve problems such as frequent switching (jittering), increased communication delay, and even link interruption caused by switching based only on reference signal strength.

[0040] 2. The present invention provides a base station switching method and system based on track prediction, which supports both aircraft-initiated switching requests and ground base stations-initiated switching requests; the ground base station comprehensively considers the network load when initiating the switching request; the signal quality threshold used by the ground base station as a switching decision condition is slightly lower than the threshold used by the aircraft as a switching decision condition.

[0041] 3. The present invention provides a base station switching method and system based on track prediction, which supports base station switching in the case of same-frequency networking of ground base stations and also supports switching in the case of different-frequency networking of ground base stations.

[0042] 4. The present invention provides a base station switching method and system based on track prediction, which is applicable to the scenario where an aircraft switches between VDL ground base stations, the scenario where an aircraft switches between LDACS ground base stations, and the scenario where an aircraft switches between ATG ground base stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0044] Figure 1 A flow chart of a base station switching method based on track prediction according to the present invention;

[0045] Figure 2 This is a schematic diagram of an aircraft initiating a handover request in Embodiment 1 of the present invention;

[0046] Figure 3 This is a schematic diagram of a ground base station initiating a handover request in Embodiment 1 of the present invention;

[0047] Figure 4 The present invention is a structural block diagram of a base station switching system based on track prediction. DETAILED DESCRIPTION

[0048] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0049] The present invention proposes a base station switching method based on track prediction between aircraft and ground base stations in the field of civil aviation mobile communications. The core is to select the candidate station closest to the next waypoint to establish an air-to-ground communication connection when the signal quality of multiple candidate base stations is equivalent. The present invention improves the predictability of ground base station switching scenarios and air-to-ground collaboration capabilities to solve problems such as frequent switching, link interruption, and increased communication delay caused by switching only with reference to signal strength.

[0050] The present invention is applicable to both same-frequency switching and different-frequency switching scenarios, and the ground networking method is more flexible. The following embodiments discuss the implementation methods of ground base station same-frequency networking and different-frequency networking respectively.

[0051] Example 1

[0052] like Figure 1 As shown, the present invention provides a base station switching method based on track prediction, which is suitable for base station switching between an aircraft and multiple ground base stations, where the ground base stations are networked in the same frequency or in different frequencies; the method includes:

[0053] The ground base station currently establishing the connection sends uplink messages and reference messages to the aircraft in real time, and other ground base stations send reference messages to the aircraft in real time;

[0054] The aircraft establishes a list of ground base stations according to the uplink message and reference signal received from the ground base station; and updates the list of ground base stations each time an uplink message or reference signal is received from the ground base station;

[0055] The aircraft periodically analyzes the list of ground base stations, selects ground base stations whose signal quality is on an upward trend and is higher than a set threshold as candidate stations, and establishes a list of candidate stations;

[0056] The aircraft sends a message to the ground base station management system with its own identity information, next waypoint, and a list of preferred alternative stations;

[0057] The ground base station management system establishes an aircraft list based on the messages received from the aircraft and executes the switching of the ground base stations.

[0058] like Figure 2 and Figure 3 As shown, this embodiment is implemented by networking the ground base stations with the same frequency, and the switching process involves the following interactions between the aircraft and the ground base station:

[0059] (1) The ground base station currently establishing a connection sends an uplink message to the aircraft in real time, carrying its own identity information and location information;

[0060] (2) The ground base station currently establishing a connection sends a reference signal to the aircraft in real time, and the reference signal carries its own identity information, its own location information, the identity information of the neighboring station, the location information of the neighboring station, and the frequency information of the neighboring station.

[0061] It should be noted that other ground base stations only send reference messages to aircraft in real time;

[0062] (3) The aircraft establishes a list of ground base stations based on the uplink message and reference signal received from the ground base station; and updates the list of ground base stations each time an uplink message or reference signal is received from the ground base station;

[0063] Each ground base station includes at least the following information: ground base station identity information, ground base station location information, current signal quality, signal quality historical data, ground base station frequency information and neighboring station information, wherein the neighboring station information includes neighboring station identity information, neighboring station location information and neighboring station frequency information.

[0064] (4) The aircraft periodically analyzes the list of ground base stations, selects ground base stations whose signal quality is on an upward trend and is higher than a set threshold as candidate stations, and establishes a list of candidate stations;

[0065] Specifically, step (4) includes: A, analyzing the signal quality historical data, and selecting the ground base stations (excluding the base station currently connected) whose signal quality is on an upward trend and higher than the set threshold as candidate stations; B, sorting the candidate stations based on the distance relative to the next waypoint to form a list of candidate stations; in the sorting process, those with closer distances have higher priority.

[0066] (5) The aircraft sends a message to the ground base station management system and carries its own identity information, the next waypoint, and a list of preferred alternative stations (obtained through step (4), which only contains the identity information of the alternative stations);

[0067] (6) The ground base station management system establishes an aircraft list based on the messages received from the aircraft. Each aircraft includes at least the following information: aircraft identity information, signal quality, next waypoint, the ground base station currently connected, and a list of alternative stations.

[0068] And execute the handover of the ground base station, where the handover of the ground base station can be initiated by either the aircraft or the ground base station, including:

[0069] C. When the aircraft detects that the signal quality of the ground base station currently connected is lower than the set threshold, the aircraft initiates a switching request to the ground base station system and selects the ground base station with the highest ranking from the candidate list as the ground base station to be switched to;

[0070] D. When the ground base station management system detects that the aircraft signal quality is lower than the set threshold, it comprehensively considers the current network load situation, selects a ground base station from the candidate station list sent by the aircraft, and actively requests the aircraft to switch to the ground base station.

[0071] It should be noted that: compared with the handover initiated by the aircraft, the handover initiated by the ground base station system takes into account the network load and is closer to the optimal choice. Therefore, the signal quality threshold that triggers the ground base station to initiate the handover can be slightly lower than the signal quality threshold that triggers the aircraft to initiate the handover. If the aircraft switches to a ground base station with a capacity close to saturation, the ground base station can request the aircraft to switch to the second best ground base station in the candidate station list.

[0072] Example 2

[0073] The difference between this embodiment and embodiment 1 is that this embodiment is implemented by using different frequency networking between ground base stations, and the handover process involves the following differences in the interaction between the aircraft and the ground base station:

[0074] If the ground base stations use different frequency networking (considering that the signals of each ground base station will interfere with each other, each ground base station / cell uses a different frequency), the aircraft starts frequency scanning when the signal quality is detected to be lower than the set threshold, and the scanning frequency is the frequency in the neighboring station information contained in the reference signal of the ground base station. After completing the frequency scanning, the aircraft will also generate the ground base station list of step (3) in Example 1.

[0075] Inter-frequency switching can also be initiated by the aircraft or ground base station:

[0076] E. When the aircraft detects that the signal quality of the currently connected ground base station is lower than the set threshold, the aircraft will select the ground base station closest to the next waypoint from the ground base station list for switching. Since it is a frequency switching, the aircraft will reset the frequency of the ground base station;

[0077] F. When the ground base station management system detects that the aircraft signal quality is lower than the set threshold, the ground base station actively requests the aircraft to switch to the ground base station that is closest to the next waypoint and has unsaturated capacity (step (5) of Example 1, the message sent by the aircraft to the ground base station carries the next waypoint information).

[0078] The advantages of the present invention are as follows: (1) it supports both aircraft initiating switching requests and ground base stations initiating switching requests; (2) the ground base station comprehensively considers the network load when initiating the switching request; (3) the signal quality threshold used by the ground base station as a switching decision condition is slightly lower than the threshold used by the aircraft as a switching decision condition; (4) it supports both base station switching in the case of the same-frequency networking of ground base stations and switching in the case of different-frequency networking of ground base stations; (5) it is applicable to the scenario where the aircraft switches between VDL ground base stations, and is also applicable to the scenario where the aircraft switches between LDACS ground base stations, and is also applicable to the scenario where the aircraft switches between ATG ground base stations.

[0079] Example 3

[0080] like Figure 4 As shown, the difference between this embodiment and embodiment 1 is that this embodiment provides a base station switching system based on track prediction, which is suitable for base station switching between an aircraft and multiple ground base stations, and the ground base stations are networked in the same frequency or in different frequencies; the system includes:

[0081] The first message sending unit is used for the ground base station currently establishing a connection to send an uplink message and a reference message to the aircraft in real time, and other ground base stations to send a reference message to the aircraft in real time;

[0082] A base station list establishment and update unit, used for the aircraft to establish a ground base station list according to the uplink message and reference signal sent by the ground base station; and update the ground base station list each time an uplink message or reference signal sent by the ground base station is received;

[0083] An analysis and candidate station list establishment unit, used for the aircraft to periodically analyze the ground base station list, select ground base stations whose signal quality is on an upward trend and is higher than a set threshold as candidate stations, and establish a candidate station list;

[0084] The second message sending unit is used for the aircraft to send a message to the ground base station management system and carry its own identity information, the next waypoint, and a preferred alternative station list;

[0085] The base station switching unit is used for the ground base station management system to establish an aircraft list according to the received messages sent by the aircraft and execute the switching of the ground base station.

[0086] Among them, the execution process of each unit can be executed according to the process steps of a base station switching method based on track prediction in Example 1, and will not be repeated one by one in this embodiment.

[0087] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0088] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0089] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0090] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0091] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A base station switching method based on track prediction, characterized in that: The method is applicable to base station switching between an aircraft and multiple ground base stations, where the ground base stations are networked in the same frequency or in different frequencies; the method comprises: The ground base station currently establishing the connection sends uplink messages and reference messages to the aircraft in real time, and other ground base stations send reference messages to the aircraft in real time; The aircraft establishes a list of ground base stations according to the uplink message and reference signal received from the ground base station; and updates the list of ground base stations each time an uplink message or reference signal is received from the ground base station; The aircraft periodically analyzes the list of ground base stations, selects ground base stations whose signal quality is on an upward trend and is higher than a set threshold as candidate stations, and establishes a list of candidate stations; The aircraft sends a message to the ground base station management system with its own identity information, next waypoint, and a list of preferred alternative stations; The ground base station management system establishes an aircraft list based on the messages received from the aircraft and executes the switching of the ground base stations.

2. A base station switching method based on track prediction according to claim 1, characterized in that: The ground base station that currently establishes a connection carries its own identity information and location information when sending an uplink message to the aircraft in real time.

3. A base station switching method based on track prediction according to claim 1, characterized in that: When the ground base station currently establishing a connection sends a reference message to the aircraft in real time, it carries its own identity information, its own location information, neighboring station identity information, neighboring station location information and neighboring station frequency information.

4. The base station switching method based on track prediction according to claim 1, characterized in that: The ground base station list includes ground base station identity information, ground base station location information, current signal quality, signal quality historical data, ground base station frequency information and neighboring station information, and the neighboring station information includes neighboring station identity information, neighboring station location information and neighboring station frequency information.

5. A base station switching method based on track prediction according to claim 4, characterized in that: Select ground base stations whose signal quality is on an upward trend and above a set threshold as candidate stations, and establish a list of candidate stations, including: Analyze historical signal quality data and select ground base stations whose signal quality is on an upward trend and above a set threshold as candidate stations; The candidate stations are sorted based on the distance relative to the next waypoint to form a candidate station list; in the sorting process, those with shorter distances have higher priority.

6. The base station switching method based on track prediction according to claim 1, characterized in that: Perform handover of ground base stations, including: When the aircraft detects that the signal quality of the ground base station currently connected is lower than the set threshold, the aircraft initiates a switching request to the ground base station system and selects the ground base station with the highest ranking from the candidate list as the ground base station to be switched to; When the ground base station management system detects that the aircraft signal quality is lower than the set threshold, it selects a ground base station from the candidate station list sent by the aircraft in combination with the current network load and actively requests the aircraft to switch to the ground base station.

7. The base station switching method based on track prediction according to claim 1, characterized in that: The aircraft list includes aircraft identity information, signal quality, next waypoint, currently connected ground base station and candidate station list.

8. The base station switching method based on track prediction according to claim 1, characterized in that: When the ground base stations are networked with different frequencies, a list of ground base stations is established, including: When the aircraft detects that the signal quality is lower than the set threshold, it starts to scan the frequency. The scanning frequency is the neighboring station frequency included in the reference signal of the ground base station. After completing the frequency scan, the aircraft generates a list of ground stations.

9. A base station switching method based on track prediction according to claim 8, characterized in that: When the ground base stations are networked in different frequencies, the switching of the ground base stations is performed, including: When the aircraft detects that the signal quality of the currently connected ground base station is lower than the set threshold, the aircraft will select the ground base station closest to the next waypoint from the ground base station list for switching, and the aircraft will reset the frequency of the ground base station; When the ground base station management system detects that the aircraft signal quality is lower than the set threshold, the ground base station actively requests the aircraft to switch to the ground base station that is closest to the next waypoint and has unsaturated capacity.

10. A base station switching system based on track prediction, characterized in that: The system is suitable for base station switching between an aircraft and multiple ground base stations, where the ground base stations are networked in the same frequency or in different frequencies; the system includes: The first message sending unit is used for the ground base station currently establishing a connection to send an uplink message and a reference message to the aircraft in real time, and other ground base stations to send a reference message to the aircraft in real time; A base station list establishment and update unit, used for the aircraft to establish a ground base station list according to the uplink message and reference signal sent by the ground base station; and update the ground base station list each time an uplink message or reference signal sent by the ground base station is received; An analysis and candidate station list establishment unit, used for the aircraft to periodically analyze the ground base station list, select ground base stations whose signal quality is on an upward trend and is higher than a set threshold as candidate stations, and establish a candidate station list; The second message sending unit is used for the aircraft to send a message to the ground base station management system and carry its own identity information, the next waypoint, and a preferred alternative station list; The base station switching unit is used for the ground base station management system to establish an aircraft list according to the received messages sent by the aircraft and execute the switching of the ground base station.

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