Differentiated enhanced cell handover method, network device and system

Abstract

The application discloses a differentiated enhanced cell switching method, network equipment and system, wherein the method comprises the following steps: acquiring service characteristics of all terminal devices in any to-be-switched cell; classifying all terminal devices in the to-be-switched cell according to the service characteristics to obtain a plurality of classification data sets and a category number; generating a total switching time length according to the number of all terminal devices; dividing the total switching time length into time segments with the same number as the category number; matching each time segment to each classification data set according to the service characteristics corresponding to each classification data set; and randomly allocating a switching timer to each terminal device in any classification data set in the matched time segment. The cell switching method can differentiate and enhance the switching time sequence of terminal devices according to different types of service requirements of the terminal devices, improve the switching success rate, and effectively enhance the rationality and stability of the switching.

Description

Technical Field

[0001] This invention relates to the field of NTN network communication cell handover technology, and in particular to a differentiated enhanced cell handover method, network equipment and system based on NTN terrestrial fixed coverage. Background Technology

[0002] In recent years, satellite communication technology has developed rapidly. Satellite communication is a key guarantee for 5G to achieve seamless network integration and extend communication space, because compared with terrestrial mobile communication technology, the biggest advantage of satellite communication is its wide-area coverage without dead zones, regardless of terrain and distance; at the same time, satellite convergence can significantly enhance the ability of 5G systems to provide continuous and uninterrupted network connectivity services to users in IoT devices and mobile carriers such as airplanes, ships, trains, and cars.

[0003] Currently, 3GPP is dedicated to research on non-terrestrial networks, with cell handover being one of its key research areas. Extensive research and discussion have been conducted on the continuity of network handover services for both fixed and mobile terrestrial cells.

[0004] In the scenario of handover between ground fixed cells, the ground fixed cells do not change with the movement of satellites. When the satellites move to a certain extent, the ground fixed cells will be covered by new satellites. During this process, the terminal equipment (UE) in the ground fixed cells needs to switch to the new satellites. A large number of UE handovers will bring huge signaling load to the satellites and may also cause UE handover failures.

[0005] Currently, the main approach to address this issue is Conditional Handover (CHO), which deals with the significant signaling load on satellites caused by a large number of UE handovers during fixed-cell handover. This method determines the handover time for the target satellite based on information such as ephemeris tables, satellite speed, and direction. Then, a random timer is pre-assigned to each UE in the fixed-cell, allowing them to sequentially access the target satellite according to their timer selections. This discretizes the handover time for each UE, preventing a large number of UEs from switching simultaneously and thus improving the handover success rate. However, with the rapid development of communication services and the diverse needs of various terminals, the random timer allocation method may not meet the needs of users with high service demands, preventing them from receiving priority handovers and causing inconvenience. Summary of the Invention

[0006] The purpose of this invention is to provide a differentiated enhanced cell handover method, network device, and system based on NTN terrestrial fixed coverage that can allocate communication cell handover timing based on the service characteristics of the terminal.

[0007] To achieve the above objectives, this invention discloses a differentiated enhanced cell handover method based on NTN terrestrial fixed coverage, comprising:

[0008] Obtain the service characteristics of all terminal devices in any cell to be handed over;

[0009] Based on the classification algorithm and the business characteristics, all terminal devices in the cell to be switched are classified to obtain several classification datasets and the number of categories.

[0010] The total handover duration is generated based on the number of all terminal devices in the cell to be handed over;

[0011] The total switching time is divided into time periods equal to the number of categories, and the duration of each time period is positively correlated with the proportion of terminal devices in the corresponding category;

[0012] Based on the business characteristics corresponding to each of the classification datasets, each time period is matched to each of the classification datasets respectively;

[0013] For any of the classification datasets, within the matched time period, a switching timer is randomly assigned to each of the terminal devices in the classification dataset.

[0014] Preferably, all terminal devices in the cell to be handed over are classified using an unsupervised learning method based on clustering.

[0015] Preferably, the service characteristics include the priority and QoS characteristics of the PDU session.

[0016] Preferably, the QoS features include bandwidth, latency, jitter, and packet loss rate.

[0017] Preferably, the terminal devices are classified using network data analysis functions in the core network.

[0018] Preferably, the total handover duration is generated by the policy control function in the core network, and the total handover duration is divided into several time periods. The policy control function also performs the matching of the time periods with the classification dataset.

[0019] Preferably, a switching timer is randomly assigned to each terminal device in each of the classified datasets through the access and mobility management functions in the core network.

[0020] The present invention also discloses a network device that switches the connection between a terminal device and a satellite based on the differentiated enhanced cell handover method according to any one of claims 1 to 7.

[0021] The present invention also discloses a network system comprising:

[0022] One or more processors;

[0023] Memory;

[0024] And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the differentiated enhanced cell handover method as described above.

[0025] The present invention also discloses a computer-readable storage medium comprising a computer program that can be executed by a processor to perform the differentiated enhanced cell handover method as described above.

[0026] Compared with existing technologies, the cell handover method disclosed in the above-mentioned technical solution of this invention takes into account the service requirements of terminal equipment during satellite communication cell handover, rationally classifies terminal equipment in ground fixed cells, and allocates timers to different handover time periods according to different categories. Thus, for some terminal equipment with high service requirements, the handover time period can be obtained earlier, while the handover time of some terminal equipment with low service requirements is postponed. Therefore, the above-mentioned cell handover method can differentiate and enhance the handover time of terminal equipment according to different types of service requirements, improve the handover success rate, and effectively enhance the rationality and stability of handover. Attached Figure Description

[0027] Figure 1 This is a flowchart of the cell handover method in an embodiment of the present invention.

[0028] Figure 2 This is a flowchart illustrating the signaling execution process of the cell handover method in an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of satellite coverage of a fixed ground cell in an embodiment of the present invention. Detailed Implementation

[0030] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0031] This embodiment discloses a communication cell handover method for use in satellite communication networks with NTN (Network Telecommunication Network) terrestrial fixed coverage. For NTN handover scenarios with terrestrial fixed coverage cells, the satellite cell coverage area does not continuously move with the satellite's movement. Figure 3As SAT#A moves along its satellite orbit, it always covers a fixed area on the ground. When it moves to the position of SAT#A', the fixed ground cell is about to lose its coverage. At this time, the target satellite SAT#B continues to cover the original fixed cell. This requires the terminal equipment in the cell to be switched to SAT#B. The switching method in this embodiment is an optimization of this switching process.

[0032] like Figure 1 The cell handover method in this embodiment includes the following steps:

[0033] S1: Obtain the service characteristics of all terminal devices in any cell to be handed over;

[0034] S2: Based on the classification algorithm and business characteristics, classify all terminal devices in the cell to be switched to obtain several classification datasets and the number of categories.

[0035] S3: Generate the total handover duration based on the number of all terminal devices in the cell to be handed over;

[0036] S4: Divide the total switching time into time periods equal to the number of categories, and the duration of each time period is positively correlated with the proportion of terminal devices in the corresponding category;

[0037] S5: Based on the business characteristics corresponding to each category dataset, match each time period to each category dataset respectively;

[0038] S6: For any classification dataset, within the matched time period, randomly assign a switching timer to each terminal device in the classification dataset.

[0039] Specifically, terminal devices are classified using the Network Data Analysis Function (NWDAF) in the core network.

[0040] The PCF (Policy Control Function) in the core network generates the total handover duration and divides the total handover duration into several time periods. The PCF also performs the matching of time periods with the classification dataset.

[0041] The Access and Mobility Management Function (AMF) in the core network randomly assigns a handover timer to the terminal devices in each classification dataset.

[0042] In addition, service characteristics include the priority and QoS characteristics of PDU sessions. Specifically, QoS characteristics include bandwidth, latency, jitter, and packet loss rate.

[0043] The signaling execution flow for the above handover method is as follows: Figure 2 The details are as follows:

[0044] 1. The terminal device (UE) initially accesses the satellite network via SAT#A;

[0045] 2. When SAT#A is about to be separated from the current communication cell, the AMF initiates a handover policy request to the PCF. The request message includes: request event ID (satellite handover policy), source satellite ID (i.e., SAT#A ID), the expected duration of SAT#A coverage of the fixed cell, target satellite ID (i.e., SAT#B ID), the expected time for SAT#B to take over the fixed cell, fixed cell ID, etc.

[0046] 3. The PCF initiates a handover strategy analysis request to the NWDAF. The request message includes: Request Event ID (Satellite Handover Analysis), Source Satellite ID (i.e., SAT#A ID), SAT#A's expected coverage duration of the fixed cell, Target Satellite ID (i.e., SAT#B ID), SAT#B's expected takeover time of the fixed cell, Fixed Cell ID, Analysis Type (Fixed Cell UE Classification), and other information.

[0047] 4. NWDAF responds to PCF's request;

[0048] 5. PCF responds to AMF's request;

[0049] 6. When SAT#A is about to end its coverage (e.g., 5 seconds before SAT#A ends its coverage), NWDAF requests the AMF to obtain the list of UEs currently accessing SAT#A. The request includes: the UE ID currently accessing SAT#A, the number of PDU sessions, the priority of the PDU sessions, and the QoS (throughput, latency, jitter, packet loss rate) of the PDU sessions.

[0050] 7. AMF returns a list of UEs currently connected to SAT#A;

[0051] 8. NWDAF performs handover strategy analysis based on the obtained list of UEs currently accessing SAT#A (i.e., analysis based on the handover method described above) and obtains the analysis results;

[0052] 9. NWDAF will notify PCF of the analysis results;

[0053] 10. The PCF generates a handover strategy (i.e., a handover timer allocated to each UE) based on the analysis results and sends it to the AMF;

[0054] 11. AMF forwards the switching policy to SAT#A;

[0055] 12. SAT#A will broadcast the handover policy to each UE;

[0056] 13. When the communication cell is covered by SAT#B, the UE will sequentially access SAT#B according to the handover timer assigned to it.

[0057] The following example will further illustrate the execution process of the above cell handover method.

[0058] Suppose that 10,000 terminal devices (UEs) in the fixed ground cell currently covered by satellite A need to switch to satellite B.

[0059] First, based on the current service characteristics of each UE, NWDAF divides the 10,000 UEs into the following three categories:

[0060] Category 1: 5000 voice service UEs;

[0061] Category 2: 3000 video service UEs;

[0062] Category 3: 2000 web browsing service users.

[0063] Then, the PCF generates a total handover duration of 2 seconds based on the total number of UEs (10,000). It should be noted that the handover duration for each UE is preset, so it can also be said that the total handover duration is generated based on preset data.

[0064] Next, the total switching time of 2 seconds is divided into 3 time periods: T1, T2, and T3.

[0065] T1: 0-1 second, accounting for 5 / 10 of the total duration;

[0066] T2: 1-1.6 seconds, accounting for 3 / 10 of the total duration;

[0067] T3: 1.6-2 seconds, accounting for 2 / 10 of the total duration.

[0068] Then, based on the service characteristics of various UEs, PCF matches the three time periods T1, T2, and T3 to three categories:

[0069] T1 (0-1 second) matches a UE with a Class 1 voice service;

[0070] T2 (1-1.6 seconds) matched a Class 2 video service UE;

[0071] T3 (1.6-2 seconds) matched a Class 3 webpage UE.

[0072] Next, the AMF randomly assigns a handover timer to each UE in each class:

[0073] For Class 1 voice service UEs: the handover timer is randomly allocated within a time period of 0-1 seconds. For example, the overflow time of the handover timer allocated to one of the Class 1 UEs is 0.3 seconds.

[0074] For Class 2 video service UEs, the handover timer is randomly allocated within a time period of 1-1.6 seconds. For example, the overflow time of the handover timer allocated to one of the Class 2 UEs is 1.2 seconds.

[0075] For Class 3 web page service UEs, the handover timer is randomly allocated within a time period of 1.6-2 seconds. For example, the overflow time of the handover timer allocated to one of the Class 3 UEs is 1.8 seconds.

[0076] When the handover timer overflows, the UE begins to switch to satellite B.

[0077] The aforementioned cell handover method incorporates the service requirements of terminal devices during satellite communication cell handover. Terminal devices in fixed terrestrial cells are rationally categorized, and timers are allocated to different categories for different handover time periods. This allows terminal devices with high service requirements to receive earlier handover time slots, while those with lower service requirements are given later handover times. Therefore, this handover method can rationally categorize UEs and allocate handover timers based on service requirements, achieving a smooth and orderly cell handover.

[0078] On the other hand, clustering-based unsupervised learning methods classify all terminal devices in the cell to be handed over.

[0079] The theoretical foundation of cluster-based unsupervised learning methods is cluster analysis. Cluster analysis is a statistical method that studies the inherent patterns and characteristics of data to group similar objects or data points into the same class, while grouping dissimilar objects or data points into different classes.

[0080] The specific implementation steps of this classification method are as follows:

[0081] 1. Given the number of categories K: In this step, a range for the number of categories needs to be predefined, for example, [2, 10]. This range can be set according to the current dataset size, dataset characteristics, and actual needs;

[0082] 2. Normalize / standardize the dataset: This step is to make features at different scales comparable. Common normalization methods include min-max normalization and Z-score standardization;

[0083] 3. Randomly select K data points from the dataset as the initial centers of the K classes;

[0084] 4. Calculate the distance between each data point in the dataset and the K class centers. Common distance metrics include Euclidean distance, cosine similarity, and Manhattan distance. The smaller the distance, the more similar the data point is to the class center. Then, assign the data point to the class of the class center that is closest to the K class centers, so that each data point is assigned to the most similar class.

[0085] 5. Based on step 4, divide all the data into K categories, and then recalculate the centers of these K categories;

[0086] 6. Repeat steps 4 and 5. If the distance between the recalculated class center and the original class center is less than a certain set threshold, then terminate the classification.

[0087] 7. Iterate through steps 1 to 6, calculate the sum of squared errors of the data for different number of categories K, and plot the line graph of the sum of squared errors for the corresponding K values. Observe the optimal value of the number of categories K using the elbow method.

[0088] In another preferred embodiment of the present invention, a network device is also disclosed, which switches the connection between a terminal device and a satellite based on the cell handover method described above.

[0089] This invention also discloses a network system comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the cell handover method as described above. The processors may be general-purpose central processing units (CPUs), microprocessors, application-specific integrated circuits (ASICs), or one or more integrated circuits, used to execute relevant programs to implement the functions required by the modules in the network system of this application embodiment, or to execute the cell handover method of this application method embodiment.

[0090] The present invention also discloses a computer-readable storage medium comprising a computer program executable by a processor to perform the cell handover method described above. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center integrating one or more available media. The available medium can be read-only memory (ROM), random access memory (RAM), or magnetic media, such as floppy disks, hard disks, magnetic tapes, magnetic disks, or optical media, such as digital versatile discs (DVDs), or semiconductor media, such as solid-state drives (SSDs).

[0091] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. The processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the aforementioned cell handover method.

[0092] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for differentiated enhanced cell handover based on NTN ground fixed coverage, characterized in that, include: Obtain the service characteristics of all terminal devices in any cell to be handed over; Based on the classification algorithm and the business characteristics, all terminal devices in the cell to be switched are classified to obtain several classification datasets and the number of categories. The total handover duration is generated based on the number of all terminal devices in the cell to be handed over; The total switching time is divided into time periods equal to the number of categories, and the duration of each time period is positively correlated with the proportion of terminal devices in the corresponding category; Based on the business characteristics corresponding to each of the classification datasets, each time period is matched to each of the classification datasets respectively; For any of the classification datasets, within the matched time period, a switching timer is randomly assigned to each of the terminal devices in the classification dataset.

2. The method of claim 1, wherein the NTN ground fixed coverage based differentiated enhanced cell handover method is characterized by, An unsupervised learning method based on clustering is used to classify all terminal devices in the cell to be handed over.

3. The method of claim 1, wherein the NTN ground fixed coverage based differentiated enhanced cell handover method is characterized by, The service characteristics include the priority and QoS characteristics of the PDU session.

4. The method of claim 3, wherein the NTN ground fixed coverage based differentiated enhanced cell handover method is characterized by, The QoS features include bandwidth, latency, jitter, and packet loss rate.

5. The method of claim 1, wherein the NTN ground fixed coverage based differentiated enhanced cell handover method is characterized by, The terminal devices are classified using network data analysis functions in the core network.

6. The differentiated enhanced cell handover method based on NTN terrestrial fixed coverage according to claim 1, characterized in that, The total handover duration is generated by the policy control function in the core network, and the total handover duration is divided into several time periods. The policy control function also performs the matching of the time periods with the classification dataset.

7. The differentiated enhanced cell handover method based on NTN terrestrial fixed coverage according to claim 1, characterized in that, A handover timer is randomly assigned to each terminal device in each of the classification datasets through the access and mobility management functions in the core network.

8. A network device, characterized in that, The network device switches the connection between the terminal device and the satellite based on the differentiated enhanced cell handover method according to any one of claims 1 to 7.

9. A network system, characterized in that, include: One or more processors; Memory; And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the differentiated enhanced cell handover method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, Includes a computer program that can be executed by a processor to perform the differentiated enhanced cell handover method as described in any one of claims 1 to 7.

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