Space-air-ground integrated network architecture based on non-cellular network and network switching method

Abstract

The application provides a space-air-ground integrated network architecture based on a non-cellular network and a network switching method. The network architecture according to the application comprises a space layer, an air layer and a ground layer. The space layer is used for providing communication services for a first communication area. The air layer is provided with a low-altitude communication system based on a non-cellular network architecture, which is used for providing communication services for a second communication area. The low-altitude communication system comprises a low-altitude communication core network, a non-cellular wireless access network and a terminal. The low-altitude communication core network is used for communication management of the terminal. The non-cellular wireless access network is used for providing a connection channel for the low-altitude communication core network and the terminal. The terminal is used for initiating an access request and receiving control data. The ground layer is used for providing communication services for a third communication area. The network architecture according to the application eliminates the vertical coverage blind area of the traditional network, and the corresponding network switching method solves the problems of complex switching process, unstable communication link and the like of the existing space-air-ground integrated network.

Description

Technical Field

[0001] This invention relates to the field of communication network architecture technology, and in particular to an integrated air-space-ground network architecture and network handover method based on a non-cellular network. Background Technology

[0002] Low-altitude airspace typically refers to the airspace within 1000 meters of the ground, and can extend to within 3000 meters depending on regional characteristics and actual needs. Low-altitude flight requires a stable air-to-ground communication link to send control commands and emergency response orders to aircraft in real time, ensuring flight safety. The low-altitude communication system is a crucial foundation for building a low-altitude airspace management system and directly impacts the success or failure of low-altitude flight control.

[0003] Traditional cellular networks rely on a large number of fixed base stations for coverage. In the low-altitude airspace (120 to 3000 meters) over cities, traditional cellular networks lack effective communication capabilities and struggle to meet the demand for full air-space-ground coverage. Furthermore, they suffer from high handover latency, poor service quality for edge users, and high construction costs. Existing integrated air-space-ground networks mostly employ a layered heterogeneous architecture, but significant protocol differences exist between satellite networks, air-level networks, and terrestrial networks, leading to complex handover processes and difficulties in adapting to dynamic changes through centralized resource management. Cellular-free network technology, through distributed antennas and cooperative transmission, can improve network capacity and coverage uniformity, but its application in air-space-ground scenarios is still immature.

[0004] The following problems exist with current integrated air-space-ground networks and their network handover methods:

[0005] 1. In the low-altitude airspace range of 120 meters to 3000 meters above cities, there is a lack of effective communication methods. Traditional terrestrial 4G / 5G public networks are limited by the cellular communication system and have difficulty covering the low-altitude airspace. In addition, continuous air coverage requires a high site density. Traditional cellular base stations have serious cell overlap when providing air coverage, making cell boundary management difficult. The relationship between base station neighboring cells is extremely complex, making it difficult to achieve smooth handover across cells. In particular, the communication link quality above 120 meters is severely degraded, which cannot meet the needs of low-altitude services. At the same time, large-scale construction of base stations will also lead to high construction and maintenance costs.

[0006] 2. Existing public ground network communication technologies have poor communication coverage continuity in remote areas, with many communication coverage blind spots, which seriously affect the stable and reliable transmission of communication data between the low-altitude airspace control system and low-altitude aircraft.

[0007] 3. Existing integrated air-space-ground networks mostly adopt a layered heterogeneous architecture, but there are significant differences in protocols between satellite networks, air-space networks and terrestrial networks, and the switching process is complex, resulting in unstable communication links and difficulty in adapting centralized resource management to dynamic changes. Summary of the Invention

[0008] The purpose of this invention is to provide an integrated air-space-ground network architecture and network handover method based on a non-cellular network, aiming to solve the above-mentioned problems in the prior art.

[0009] This invention provides an integrated air-space-ground network architecture based on a non-cellular network, comprising a space layer, an air layer, and a ground layer that are communicatively connected to each other;

[0010] The spatial layer is used to provide communication services for the first communication area;

[0011] The air layer includes a low-altitude communication system based on a non-cellular network architecture, used to provide communication services for the second communication area. The low-altitude communication system comprises a low-altitude communication core network, a non-cellular radio access network, and terminals connected in sequence. The low-altitude communication core network manages the communication of the terminals. The non-cellular radio access network provides a connection channel between the low-altitude communication core network and the terminals. The terminals initiate access requests and receive control data.

[0012] The ground layer is used to provide communication services for the third communication area.

[0013] This invention provides a method for integrated air-space-ground network handover based on cellular-free networks, comprising:

[0014] Continuous monitoring of communication networks at the space, air, and ground levels is achieved through terminals;

[0015] Dual-channel switching is performed between the terminal and the network connections of the space layer, air layer, and ground layer based on the signal strength and load rate of the communication network.

[0016] The embodiments of the present invention can include the following beneficial effects: The embodiments of the present invention can solve the problems that public network communication cannot cover the airspace above 120 meters in low altitude and that the frequent inter-cell handover caused by the large number of public network communication sites, through the non-cellular network architecture; and the air-space-ground integrated network architecture based on non-cellular network technology eliminates the vertical coverage blind spots of traditional networks. Furthermore, by proposing a network handover method based on the air-space-ground integrated network architecture based on non-cellular network technology, the present invention solves the problems of complex handover process and unstable communication link in existing air-space-ground integrated networks. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of an integrated air-space-ground network architecture based on a non-cellular network according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of a non-cellular network system according to an embodiment of the present invention;

[0020] Figure 3 This is a diagram of a non-cellular network system architecture according to an embodiment of the present invention;

[0021] Figure 4 This is a diagram of the integrated air-space-ground network architecture according to an embodiment of the present invention;

[0022] Figure 5 This is a flowchart illustrating the handover process from the terrestrial 4G / 5G public network to the airborne non-cellular network according to an embodiment of the present invention.

[0023] Figure 6 This is a flowchart illustrating the handover process from the air layer non-cellular network to the ground layer 4G / 5G public network according to an embodiment of the present invention.

[0024] Figure 7 This is a flowchart illustrating the handover process from a space-layer satellite network to a non-cellular network in the upper atmosphere, according to an embodiment of the present invention.

[0025] Figure 8 This is a flowchart of the air-space-ground integrated network handover method based on a non-cellular network according to an embodiment of the present invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0027] System Implementation Examples

[0028] According to embodiments of the present invention, an integrated air-space-ground network architecture based on a cellular-free network is provided. Figure 1This is a schematic diagram of an integrated air-space-ground network architecture based on a non-cellular network according to an embodiment of the present invention, as shown below. Figure 1 As shown, the air-space-ground integrated network architecture based on a non-cellular network according to an embodiment of the present invention specifically includes a space layer, an air layer, and a ground layer that are interconnected with each other.

[0029] The spatial layer 10 is used to provide communication services for the first communication area;

[0030] The air layer 12 is equipped with a low-altitude communication system based on a non-cellular network architecture to provide communication services for the second communication area. The low-altitude communication system includes a low-altitude communication core network, a non-cellular radio access network, and terminals connected in sequence. The low-altitude communication core network is used for communication management of the terminals. The non-cellular radio access network is used to provide a connection channel between the low-altitude communication core network and the terminals. The terminals are used to initiate access requests and receive control data.

[0031] Specifically, the non-cellular wireless access network includes:

[0032] The radio frequency remote unit (RRU) and antenna are connected to the terminal and the edge distributed processing unit (EDU) to receive terminal signals that are allowed to access the low-altitude communication network, and to distribute control data from the EDU to the corresponding terminal.

[0033] The edge distributed processing unit (EDU) is connected to the RRU and antenna, the centralized processing unit (CU), and the user-centric distributed unit (UCDU). It is used to aggregate several RRU signals and send the aggregated signals to the CU and UCDU, as well as to send control data from the CU and UCDU to the RRU and antenna.

[0034] The EDU is deployed near the RRU and has redundant hot standby on the hardware.

[0035] The adjacent location is the network edge area of ​​the RRU; one EDU is networked with at least four RRUs;

[0036] The centralized processing unit (CU) and the user-centric distributed unit (UCDU) are connected to the EDU and the low-altitude communication core network. They are used to merge and pre-encode the data streams of the same user in the aggregated signal, send the processed data to the low-altitude communication core network, and distribute control data from the low-altitude communication core network to the corresponding EDU.

[0037] The CU and UCDU are deployed on the same hardware device and are redundantly deployed at the same site or deployed in a different disaster recovery location.

[0038] The ground layer 14 is used to provide communication services for the third communication area;

[0039] The first communication area is a wide-area high-altitude area above 3000 meters; the second communication area is a mid-to-low-altitude area between 120 meters and 3000 meters; and the third communication area is a dense urban area below 120 meters.

[0040] The following describes in detail the above-mentioned technical solutions of the present invention with reference to the specific circumstances of the air-space-ground integrated network architecture based on a non-cellular network in the embodiments of the present invention.

[0041] This invention proposes a novel integrated air-space-ground network architecture and network handover method based on non-cellular network technology. The architecture consists of a space layer (satellite), an air layer (non-cellular communication network), and a ground layer (4G / 5G public network), supporting full coverage and efficient resource management. It is applicable to satellite communication, low-altitude communication networks, and various low-altitude economic application scenarios. This invention fully utilizes the advantages of non-cellular network technology, deploying base stations at high points in cities or regions, such as television transmission towers, to solve the airspace coverage problem from 120 meters to 3000 meters above urban areas. Combined with 4G / 5G public network coverage of urban airspace below 120 meters, and with satellite network as a communication supplement, the non-cellular network, the ground-based 4G / 5G public network, and the satellite communication network together form an integrated air-space-ground network, thereby meeting the requirement for full air-space-ground coverage. Furthermore, to address issues such as significant protocol differences between satellite networks, the air layer network (non-cellular network), and the ground network, complex handover processes, and unstable communication links, an integrated air-space-ground network handover method is also proposed.

[0042] A non-cellular network system consists of a non-cellular core network, base stations, and terminals. To further improve network flexibility, a three-tier architecture is adopted: Remote Radio Unit (RRU) and Antenna + Edge Distributed Processing Unit (EDU) → Centralized Processing Unit (CU) + User-Centric Distributed Unit (UCDU) → Core Network, as detailed below. Figure 2 As shown.

[0043] UCDU and CU are logically distinct entities: UCDU primarily comprises the real-time-critical physical layer, media access layer (MAC), and radio link control layer (RLC). User-centric distributed units (UCDUs) can merge / pre-encode data streams from the same user transmitted / received by different EDUs. CUs include less real-time-critical processing, such as Packet Data Convergence Protocol (PDCP), Serving Data Adaptive Protocol (SDAP), and Radio Resource Control (RRC). In actual deployment, UCDUs and CUs are deployed on the same hardware device, with hardware redundancy and hot standby. Furthermore, the cloud-based deployment of UCDUs, CUs, and the core network can be gradually implemented subsequently.

[0044] Edge Distributed Units (EDUs) are designed to aggregate signals from multiple Remote Rugby Units (RRUs) and perform distributed baseband signal processing. Taking uplink reception as an example, such as flight status information or video stream data transmission from an aircraft's onboard terminal, the RRU receives the user data stream and then the EDU forwards it to a User-Centric Distributed Unit (UCDU). In actual deployment, the number of EDUs can vary depending on the communication scenario. A single terminal user can associate with multiple EDUs and then with a UCDU. The UCDU can merge data streams from the same user sent by different EDUs. For downlink transmission, for example, aircraft control data is distributed via the UCDU to its associated EDU, and then further distributed to the aircraft's onboard terminal via the connected RRU. In actual deployment, EDU devices should be located close to the RRU devices and have hardware redundancy and hot standby functionality.

[0045] The EDU and CU+UCDU distributed architecture features an edge distributed processing unit deployed near the network edge of the RRU, facilitating centralized management and control of the RRU. This allows for networking of one EDU with at least four RRUs. In urban areas, the CU+UCDU can be deployed in the same data center via the core network or with primary / backup redundancy for disaster recovery. The system networking diagram for the low-altitude communication solution based on a non-cellular network architecture is shown below. Figure 3 As shown.

[0046] The integrated air-space-ground network based on non-cellular network technology consists of the following layers, such as... Figure 4 As shown:

[0047] 1. Space layer: carried by satellite network, interconnected with ground gateway stations through inter-satellite laser links, providing wide-area backhaul and supplementary communication coverage;

[0048] 2. The airspace layer: carried by a non-cellular network, it mainly supports communication coverage in the low-altitude airspace from 120 meters to below 3000 meters;

[0049] 3. Ground layer: carried by 4G / 5G public network, which mainly supports airspace communication coverage below 120 meters.

[0050] For the above-mentioned integrated air-space-ground network, this invention proposes a corresponding network switching method. To maintain the stability of the communication status, this switching method adopts dual-channel switching: that is, except in special cases, both 4G / 5G public network and satellite network, or non-cellular network and satellite network, remain operational, and 4G / 5G public network and non-cellular private network should be able to switch automatically.

[0051] 1. The following are the methods for switching from the terrestrial 4G / 5G public network to the airborne non-cellular network, such as... Figure 5 As shown:

[0052] (1) When the user equipment (UE) is powered on, it accesses the 4G / 5G public network and the Star Network, and also accesses the non-cellular network, but does not transmit data.

[0053] (2) The UE continuously monitors the RSRP / SINR of the ground layer base station, the RSRP / SINR of the air layer non-cellular network base station, and its own altitude. When the difference between the air layer base station signal and the ground layer signal exceeds a certain value (e.g., 5dB) or the UE's altitude is close to 120 meters, proceed to the next step.

[0054] (3) Check whether the signal strength of the non-cellular base station in the air layer meets the basic threshold: RSRP air > RSRP basic threshold; and check the base station load rate: if the load rate is ≤80% (not overloaded), it is confirmed to be available and proceed to step 4; if it is overloaded (>80%), the handover is postponed and the process returns to step 2 to continue monitoring.

[0055] (4) Maintain existing ground layer connections (to ensure uninterrupted service) and establish new connections with the target air layer non-cellular network base station.

[0056] (5) Monitor the stability of the air layer signal (for 100ms, RSRP fluctuation <3dB, SINR ≥ target threshold); after confirming signal stability, release the ground layer connection. At this time, the UE accesses the air layer non-cellular network and StarNet. Thus, the handover from 4G / 5G public network to non-cellular network is completed.

[0057] 2. The following are the methods for switching from the air-level non-cellular network to the ground-level 4G / 5G public network, such as... Figure 6 As shown:

[0058] (1) When the UE accesses the non-cellular network and StarNet, the UE continuously monitors the RSRP, SINR and latency parameters of the non-cellular base station and the ground base station.

[0059] (2) When the UE detects that the ground layer signal is higher than the air layer signal by a certain value (e.g., 5dB) or the user's height is less than 120 meters, the ground base station is screened according to the signal strength threshold RSRP ground > RSRP basic threshold, and overloaded base stations with a load rate > 80% are excluded, and a list of candidate base stations that meet the conditions is generated.

[0060] (3) Based on the scoring algorithm Sc=0.6×ground base station signal strength+0.3×(1 / load rate)-0.1×distance, find the base station with the highest score from the candidate base station list.

[0061] (4) Maintain existing connections with non-cellular networks and establish connections with the target base station (the base station with the highest score mentioned above).

[0062] (5) Check the stability of the ground base station signal (last 100ms, RSRP fluctuation ≤3dB). After confirming stability, release the non-cellular network connection, and the handover is complete. At this time, the UE accesses the terrestrial 4G / 5G public network and satellite network.

[0063] 3. When, due to special circumstances, the UE only accesses the space-layer satellite network, but to ensure communication link stability, guarantee communication quality, or for other special reasons (such as wartime, where the satellite network may not be continuously usable), the UE needs to switch to the air-layer non-cellular network. The following are the methods for switching from the space-layer satellite network to the air-layer non-cellular network, such as... Figure 7 As shown:

[0064] (1) The UE continuously monitors the satellite signal strength and non-cellular network signal strength.

[0065] (2) Satellite signal attenuation prediction: When the predicted satellite signal strength Ssat1 is lower than the threshold Sth or the time delay Tdl is greater than the threshold Tth at a certain time in the future, the UE sends a handover request to the non-cellular base station, carrying the current channel status and location information.

[0066] The satellite predicted signal strength is:

[0067]

[0068] Where Ssat1(t+Δt) is the predicted satellite signal strength at a future time, Ssat1(t) is the current satellite signal strength, λ is the environmental attenuation coefficient, and V ue Let L be the user's moving speed (m / s), θ be the angle between the user's moving direction and the center of the satellite beam, and L be the user's moving speed (m / s). t This refers to dynamic environmental losses (including rain attenuation, building shading, etc.).

[0069] (3) The non-cellular base station selects the optimal 3 beams from multiple beams based on the UE location to form a cooperative cluster.

[0070] (4) The base station sends an RRC (Radio Resource Control) reconfiguration message to notify the UE to prepare for dual connectivity.

[0071] (5) The UE simultaneously receives signals from satellite and non-cellular base stations. After the data flow stabilizes, context migration is initiated.

[0072] (6) Satellite encrypts UE context (IP, QoS key), and the base station obtains and decrypts the context.

[0073] (7) Check the stability of the ground signal (last 100ms, RSRP fluctuation ≤3dB). If it is stable, the base station sends RRCRelease to release the satellite link; otherwise, return to step 4.

[0074] (8) The UE disconnects from the satellite connection and the handover is completed by the satellite network to the non-cellular network.

[0075] Method Implementation Examples

[0076] According to embodiments of the present invention, a method for integrated air-space-ground network handover based on cellular-free networks is provided. Figure 8 This is a flowchart of the air-space-ground integrated network handover method based on a cellular-free network according to an embodiment of the present invention, as follows: Figure 8 As shown, the air-space-ground integrated network handover method based on a non-cellular network according to an embodiment of the present invention specifically includes:

[0077] Step S801: Continuously monitor the communication networks of the space layer, air layer, and ground layer through the terminal;

[0078] Step S802 involves performing dual-channel switching of the terminal's network connections with the space layer, air layer, and ground layer based on the signal strength and load rate of the communication network. Specifically, this includes:

[0079] When the terminal is activated, it accesses the ground-level communication network and continuously monitors the signal strength of the ground-level communication network, the air-level non-cellular communication network, and the terminal's own altitude. If the difference between the air-level signal strength and the ground-level signal strength exceeds a preset threshold, or if the terminal's own altitude is close to the second communication area, the signal strength and load rate of the air-level non-cellular communication network are judged. If the signal strength of the air-level non-cellular communication network meets the basic threshold and the load rate is below the preset threshold, the connection between the terminal and the air-level non-cellular communication network is established while maintaining the connection between the terminal and the ground-level communication network. When the state of the air-level non-cellular communication network tends to be stable after the connection, the connection between the terminal and the ground-level communication network is released.

[0080] If the signal strength of the non-cellular communication network in the air layer does not meet the basic threshold, or the load rate is higher than the preset threshold, the network handover operation will be delayed and the signal strength of the ground layer communication network, the non-cellular communication network in the air layer, and the terminal's own height will be continuously monitored.

[0081] When a terminal accesses the air-layer non-cellular communication network, the signal strength of the ground layer communication network, the air-layer non-cellular communication network, and the terminal's own height are continuously monitored. If the difference between the ground layer signal strength and the air layer signal strength exceeds a preset threshold, or if the terminal's own height is lower than the second communication area and the signal strength of the ground layer communication network is greater than the basic threshold, then ground base stations are screened according to the load rate to generate a candidate base station list. A scoring algorithm is used to score each ground base station in the candidate base station list, and the ground base station with the highest score is selected as the target base station. While maintaining the connection between the terminal and the air-layer non-cellular communication network, a connection is established between the terminal and the target base station. When the state of the target base station tends to stabilize after the connection, the connection between the terminal and the air-layer non-cellular communication network is released.

[0082] When a terminal accesses the space layer communication network, it continuously monitors the signal strength of the space layer communication network and the air layer non-cellular communication network. When the predicted signal strength of the space layer is lower than a preset threshold or the signal delay of the space layer is greater than a preset threshold, the terminal sends a network handover request to the air layer non-cellular communication base station. The non-cellular communication base station selects the optimal 3 beams from multiple beams as a cooperative cluster according to the terminal's location and sends an RRC reconfiguration message to the terminal. After receiving the instruction, the terminal simultaneously receives the signals from the space layer communication network and the non-cellular communication base station and initiates context migration. When the state of the non-cellular communication base station tends to be stable, the connection between the terminal and the space layer communication network is released.

[0083] The mathematical expression for the predicted signal strength of the space layer is as follows:

[0084]

[0085] Where Ssat1(t+Δt) represents the predicted satellite signal strength at a future time, Ssat1(t) is the current satellite signal strength, λ is the environmental attenuation coefficient, and V ue L represents the user's moving speed, θ represents the angle between the user's moving direction and the center of the satellite beam, and L represents the user's moving speed. t This refers to dynamic environmental losses.

[0086] The embodiments of the present invention are method embodiments corresponding to the system embodiments described above. The specific operations of each step can be understood by referring to the description of the system embodiments, and will not be repeated here.

[0087] In summary, compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0088] 1. Breaking the static limitations of traditional cellular network wireless resource management: By utilizing an ultra-large aperture sparse antenna array, the signal gain is significantly improved, the communication distance of ordinary airborne commercial terminals is extended, and the transmission distance is effectively increased.

[0089] 2. The coverage distance of a single physical site is increased, and the number of physical sites in the construction of the communication network is reduced. In terms of user experience (service carrying), the handover between cells is reduced, packet loss is reduced, network reliability is improved, and stable and reliable data transmission is guaranteed.

[0090] 3. Strong network design customization capability: During the engineering design phase, the coverage capability of a single physical site can be customized and expanded or lightweighted according to coverage requirements, further enhancing the customization capability of wireless network solutions.

[0091] 4. Reduce network optimization difficulty: During the construction phase, the difficulty and cycle of network optimization can be reduced by significantly reducing inter-cell handover.

[0092] 5. Greater Flexibility: The coverage capability of a single physical site is fixed at the design stage and cannot be changed. Therefore, if weak coverage areas arise due to insufficient coverage distance, the only way to strengthen coverage in these areas is to add new physical sites. In contrast, cellular-free technology allows for enhanced single-point coverage distance during network optimization or maintenance phases by increasing or optimizing existing sites, resulting in greater network flexibility.

[0093] 6. Reduced engineering investment: The reduced number of physical sites can reduce the amount of engineering work in other communication subsystems (such as transmission, power supply, environmental monitoring, etc.), shorten the construction period, and reduce investment in infrastructure (optical cables, power supply, inter-station equipment and buildings, etc.).

[0094] 7. Eliminate vertical coverage blind spots in traditional networks: Eliminate vertical coverage blind spots in traditional networks through an integrated air-space-ground network architecture based on non-cellular network technology.

[0095] 8. Full-area three-dimensional coverage: The spatial layer covers a wide area of ​​high altitude, the air layer has no cellular network to adapt to the dynamic needs of low and medium altitude, and the ground layer DAS ensures ultra-dense access in cities, eliminating the vertical coverage blind spots of traditional networks.

[0096] 9. Optimize the handover process of the integrated air-space-ground network: The handover method of the integrated air-space-ground network proposed in this embodiment of the invention solves the problems of complex handover process, large latency and unstable communication link in the existing integrated air-space-ground network.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for integrated air-space-ground network handover based on cellular-free networks, characterized in that, include: The communication network in the air-space-ground integrated network architecture based on non-cellular networks is continuously monitored through the terminal; wherein, the air-space-ground integrated network architecture includes a space layer, an air layer, and a ground layer that are communicatively connected to each other; The space layer is used to provide communication services for a wide area of ​​high altitude above 3,000 meters; The air layer includes a low-altitude communication system based on a non-cellular network architecture, providing communication services for low- and medium-altitude areas ranging from 120 meters to 3000 meters. The low-altitude communication system comprises a low-altitude communication core network, a non-cellular radio access network, and terminals connected in sequence. The low-altitude communication core network manages the communication of the terminals. The non-cellular radio access network provides a connection channel between the low-altitude communication core network and the terminals. The terminals initiate access requests and receive control data. The non-cellular wireless access network specifically includes: The radio frequency remote unit (RRU) and antenna are connected to the terminal and the edge distributed processing unit (EDU) to receive terminal signals that are allowed to access the low-altitude communication network, and to distribute control data from the EDU to the corresponding terminal. The edge distributed processing unit (EDU) is connected to the RRU and antenna, the centralized processing unit (CU), and the user-centric distributed unit (UCDU). It is used to aggregate several RRU signals and send the aggregated signals to the CU and UCDU, as well as to send control data from the CU and UCDU to the RRU and antenna. The EDU is deployed in a location adjacent to the RRU and is redundantly hot-standby on the hardware; wherein, the adjacent location is the network edge area of ​​the RRU; one EDU is networked with at least 4 RRUs; and the physical distance between the EDU and the RRU is less than the physical distance between the EDU and the CU; The centralized processing unit (CU) and the user-centric distributed unit (UCDU) are connected to the EDU and the low-altitude communication core network. They are used to merge and pre-encode the data streams of the same user in the aggregated signal, send the processed data to the low-altitude communication core network, and distribute control data from the low-altitude communication core network to the corresponding EDU. The CU and UCDU are deployed on the same hardware device, and the hardware device adopts a co-site redundant deployment or a cross-site disaster recovery deployment. The ground layer is used to provide communication services for dense urban areas below 120 meters; Dual-channel switching is performed on the terminal's network connections to the space, air, and ground layers based on the signal strength and load rate of the communication network; specifically including: When the terminal is activated, it accesses the ground-level communication network and continuously monitors the signal strength of the ground-level communication network, the air-level non-cellular communication network, and the terminal's own altitude. If the difference between the air layer signal strength and the ground layer signal strength exceeds a preset threshold, or if the terminal's altitude has entered the low-to-medium altitude region of 120 meters to 3000 meters, the signal strength and load rate of the air layer non-cellular communication network will be obtained and judged by the EDU deployed at the edge of the RRU network. If the signal strength of the non-cellular communication network in the air layer is greater than or equal to the basic threshold and the load rate is less than or equal to the overload threshold, then the connection between the terminal and the non-cellular communication network in the air layer is established while maintaining the connection between the terminal and the ground layer communication network; when the signal strength fluctuation of the non-cellular communication network in the air layer is less than the preset range and the duration is greater than the preset duration, then the connection between the terminal and the ground layer communication network is released. If the signal strength of the non-cellular communication network in the air layer is less than the basic threshold, or the load rate is greater than the overload threshold, the network handover operation will be delayed and the signal strength of the ground layer communication network, the non-cellular communication network in the air layer, and the terminal's own height will be continuously monitored. When the terminal accesses the non-cellular communication network in the air layer, it obtains the signal strength of the ground layer communication network through the EDU deployed at the edge of the RRU network, and continuously monitors the signal strength of the ground layer communication network, the non-cellular communication network in the air layer, and the terminal's own altitude. If the difference between the ground layer signal strength and the air layer signal strength exceeds a preset threshold, or if the terminal's own height is below 120 meters and the signal strength of the ground layer communication network is greater than the basic threshold, then the ground base stations are screened according to the load rate to generate a candidate base station list. A scoring algorithm is used to score each ground base station in the candidate base station list, and the ground base station with the highest score is selected as the target base station. While maintaining the connection between the terminal and the non-cellular communication network in the air layer, a connection between the terminal and the target base station is established. When the signal strength fluctuation of the target base station is less than the preset range and the duration is greater than the preset duration, the connection between the terminal and the non-cellular communication network in the air layer is released. When the terminal accesses the space layer communication network, the signal strength of the space layer communication network and the air layer non-cellular communication network is continuously monitored; When the predicted signal strength of the space layer is lower than a preset threshold or the signal delay of the space layer is greater than a preset threshold, the terminal sends a network handover request to the non-cellular communication base station in the air layer. The non-cellular communication base station selects the optimal 3 beams from multiple beams as a cooperative cluster based on the terminal's location and sends an RRC reconfiguration message to the terminal. After receiving the instruction, the terminal simultaneously receives signals from the space layer communication network and the non-cellular communication base station, and the non-cellular communication base station obtains the terminal context from the core network. When the signal strength fluctuation of the non-cellular communication base station is less than the preset range and the duration is longer than the preset duration, the connection between the terminal and the space layer communication network is released.

2. The method according to claim 1, characterized in that, The mathematical expression for the predicted signal strength of the space layer is: Official 1; in, This indicates the predicted satellite signal strength at a future time. The current satellite signal strength, Environmental degradation coefficient, For user movement speed, The angle between the user's direction of movement and the center of the satellite beam. This refers to dynamic environmental losses.

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